# Dumb question on R8 (i think) spindle



## r-mm

My enco knee mill has what i am fairly sure is an R8 spindle however it has no keyway nor can I find any other means of preventing the drawbar from rotating the collet. 

Am I missing something? R8 collets fit snuggly.


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## Jim F

Can you feel inside where a pin or key may have been sheared ?


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## Ulma Doctor

often the key is worn on well used machines and may not be pronounced.
my BP key is in bad shape, but the taper is good.
i have no problems with collets rotating


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## Shootymacshootface

There should have been a key at some point. I know that there are plenty of mills in use that the key has been sheared off.


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## r-mm

I did my best to feel all around inside and could find no key/pin or evidence of one previously having lived in there. 

A friend pointed me to many threads with people saying they prefer R8 with no key.  Is there a trick to getting the drawbar to tighten and not spin the collet/spindle?


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## middle.road

and mine is sheared off also...
Make sure it is very clean and then I just push mine up until it 'takes', then it tightens.


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## Shootymacshootface

r-mm said:


> I did my best to feel all around inside and could find no key/pin or evidence of one previously having lived in there.
> 
> A friend pointed me to many threads with people saying they prefer R8 with no key.  Is there a trick to getting the drawbar to tighten and not spin the collet/spindle?


You need to use the brake while tightening the collet. Make sure the threads work together with zero effort, and there is no oil in the taper or on the collet.


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## r-mm

Another dumb question... does every mill have a brake?  I can't find one on my Enco 100-5200 which is similar to Grizzley G0731.  I don't see a brake in the manual for that mill.


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## vecair

r-mm said:


> My enco knee mill has what i am fairly sure is an R8 spindle however it has no keyway nor can I find any other means of preventing the drawbar from rotating the collet.
> 
> Am I missing something? R8 collets fit snuggly.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 345873
> 
> View attachment 345874




Pull out your drawbar and make sure it threads into your collets without binding up.  If it binds the collet will spin.   Might have to be die chased to clean up the threads. A bid of grease on the threads helps as well.


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## cathead

The key on my Enco knee mill went away years ago all by itself.  I use a little oil on the threads occasionally
and have not ever noticed slippage.


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## tjb

Mine is missing, too.  I know it was there when I bought the mill - a very lightly used Vectrax.  I could feel it, but at some point it evidently sheared off.  I only realized it when it occurred to me collets mounted way too conveniently, and it wasn't necessary to hunt for alignment.  I have never had any issues since realizing it was gone.  I have a power drawbar that makes tightening very simple.  I have never noticed any evidence of slippage.

I thought about looking into what it would take to fix it, but as Yogi said, "If it ain't broke, don't break it."  Sounded like wise counsel to me.

Regards,
Terry


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## r-mm

Thanks for the feedback guys I will clean up the drawbar and Collett and try again this evening. I had no idea a power drawbar was a thing I guess I learned something new.


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## RJSakowski

Looking at your second photo, I see a set screw in the quill.  That set screw is a dog point set screw on some mills and the point forms the key.  The set screw may just be backed out too far or the tip may be sheared off.  It is possible there is a second locking set screw too. 

Another thought is to clean and degrease the outer surface of the collets and the mating socket.  Any oil or grease on those surfaces will encourage collet spin while tightening the drawbar in the event that the key is missing.


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## r-mm

I am new to this mill and do not have its parts diagram, am relying on the Grizzley diagram so forgive a maybe naive question.  You are talking about this set screw?   I can remove it and have a look inside if that's what you are referring to.


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## r-mm

From the Grizzley manual.   Is this the key/pin?  If the Enco has one I really can not see or feel it.  

To get to it,  it looks to me like the spindle collar on the bottom must come off, then I would presume the spindle gets pressed out of the pulley.


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## Tozguy

In my experience the keyway is too handy to give up. It is worth reactivating that function if possible.
I like to keep some light grease on the outside of the collet so that it closes more easily than when the surfaces are clean and dry. The pin that goes in the keyway only has to prevent the collet from spinning until it is tight. The pin does not work that hard to 'hold' the collet while tightening the drawbar. It is like having a third hand.


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## RJSakowski

r-mm said:


> I am new to this mill and do not have its parts diagram, am relying on the Grizzley diagram so forgive a maybe naive question.  You are talking about this set screw?   I can remove it and have a look inside if that's what you are referring to.


Actually, it would be in the spindle itself. The set screw may plug the opening providing access to the spindle key.  I can't think of another reason for a set screw in the quill.  The G0755 actually had a slot in the quill, a throwback to when Morse tapers were used?


r-mm said:


> From the Grizzley manual.   Is this the key/pin?  If the Enco has one I really can not see or feel it.
> 
> To get to it,  it looks to me like the spindle collar on the bottom must come off, then I would presume the spindle gets pressed out of the pulley.


 The key would be the little dot on the lower right side of the drawing of P/N 130.  The parts list doesn't show it as a separate part.


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## r-mm

Thanks that is very helpful.  I'll remove the set screw on the quill to see.  If no access there I'll have to consider whether or not I want to pull the spindle.


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## RJSakowski

I don't low if this parts list is applicable to your mill but it looks like part no. 141 on page 50 is the key and lock screw.


			https://industrialmanuals.com/100-mo-987.php?manu_id=725


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## Mitch Alsup

r-mm said:


> Another dumb question... does every mill have a brake?  I can't find one on my Enco 100-5200 which is similar to Grizzley G0731.  I don't see a brake in the manual for that mill.



My G0730 has no spindle brake


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## MrWhoopee

The set-screw you have circled in your picture is too high to be they key (hold a collet next to the spindle). It is usually under the collar at the bottom of the spindle. I wouldn't be spending any time trying to replace it. When I owned my shop we would just remove them when they got damaged (which always happened sooner or later). I've been fighting a damaged key in my Kent mill since I got it. This discussion has motivated me to go out and remove it.

Under no circumstances would I consider pulling the spindle to replace the key.


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## Shootymacshootface

Mitch Alsup said:


> My G0730 has no spindle brake


By what means do you keep the spindle stationary while you tighten the drawbar? Or, do you have a power drawbar?


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## aliva

Mine sheared off a few years ago and I never replaced it. It's quicker when inserting a collet I don't have to line up the collet to the pin. I understand many people never replace them for this reason. By the way I have a power drawbar.


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## kd4gij

Take the ring off the bottom of the mill and the setscrew for the key is there where I circled


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## Tim9

On my Asian RF45 clone, I have a splined wrench which I purchased from Grizzly to hold the spindle when I tighten/ loosen the drawbar.
FWIW, My mill has a set screw which acts as the “ keyway “ and it’s been sheared off too. I wouldn’t worry about it. Not an issue.









						Spindle Spline Wrench at Grizzly.com
					

Manufactured from steel, this new spline wrench was designed especially for holding the spindle spline on many Chinese made round column, square column, and other like-sized mill/drill machines and the smaller X3 sized machines. This wrench has a 28mm spline on one end for the larger machines...




					www.grizzly.com


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## Tim9

By the way, if the mill is new for you... Take care not to leave the wrench there and then turn on the machine. The sound is deafening and will scare the hell out of you. It made me jump back.


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## Mitch Alsup

Shootymacshootface said:


> By what means do you keep the spindle stationary while you tighten the drawbar? Or, do you have a power drawbar?



There is enough friction so I can take the wrench and just give it a sharp pull. 
Drawbarrs do not have to be "that" tight--they just have to register the taper so the tool is concentric with the spindle.

On the other hand, when I tighten up the ER-40 collet holder in the spindle, I use a collet wrench in one hand and my other hand on the pulley to get enough pull to cinch up the collet.


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## r-mm

My spindle mystery deepens some.

The machine came with only a JT33 Chuck.  I presumed its shank to be R8 but noted it was not in great shape.  No big deal, it can always be replaced I thought.  However on closer inspection I don't believe this to be an R8 shank at all.   I frankly do not know what it is, does anyone here? 

I now believe this non R8 shank tore up the spindle.

This is my first R8 machine so I do not know what an R8 collet should look or feel like when inserted.  A friend with showed me his R8 collets inserting flush and practically falling out when not held.  Mine R8 collets insert with resistance and stay put when not held, they need a little knocking from above to release.  Even even when tightened with the drawbar they protrude about 1/4in as pictured.

Looking for guidance here please!  

Thanks.


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## Jim F

That is NOT an R8 arbor.
JT33 is the Jacobs taper.


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## r-mm

Any idea what the arbor is?  (and is it not called a shank?)

Does the fit of my R8 collets look okay?


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## FanMan

R8 collets usually don't stick out when tight.  They should slip in relatively easily, though sometimes they need to be polished a bit, especially cheaper  ones.

Many people remove the  key or set screw, it's often more  trouble  than it's worth.  Mine (on a Jet 15) was kinda mashed and made it hard to get the collets in and out; I removed it and never missed it.  I just hold the  pulley when tightening / untightening the drawbar.


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## Tozguy

The measurement you took of the length of the taper on the mystery arbor (1.0665) should be revisited. From the picture it appears that the taper ends (or changes) at around 1/4'' from the shoulder. The length of the mystery taper would be less than what is shown.

FWIW my R8 collets do stick out a bit from the spindle and I would not be concerned about what I see in the picture you provided in post no. 28.

The look of the taper on the mystery arbor leads me to believe that it fit well in the spindle taper. Was that arbor not used by the previous owner in the mill you bought?


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## Tozguy

r-mm said:


> I now believe this non R8 shank tore up the spindle.



What damage are you referring to? Is the inner taper of the spindle in good shape? 




r-mm said:


> Any idea what the arbor is? (and is it not called a shank?)



If the arbor is removable from the chuck its called an arbor. If the shank is an integral part of the chuck, ie can not be separated from it, then its called a shank.


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## r-mm

Thanks guys.  I can get new, clean R8 collets in place and tightened without too much difficulty.  The inside of the spindle is not going to win any beauty contests but its not horrible.  A little bit of roughness that you can imagine from looking at the mystery taper.  I don't know how to be any more precise about its condition.  

Do you all recommend I get a wedge and replace the mystery arbor with a JT33-R8 or get an integral spindle chuck?  I was looking at this keyless unit from Shars:  https://www.ebay.com/itm/Tegara-1-2...al-Shank-Arbor-13mm-NEW-Taiwan-A/350890798382
I've not used a keyless but always admired them.


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## Illinoyance

A lot of machinists remove the screw (key) as a matter of convenience.  Mine will go next week. I can't hold the d'Andrea boring head and rotate to find the key.  The Volstro rotary head is even worse to install.


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## Dabbler

OK guys, I think that I need to show a contrary opinion on this 'removing the set screw in an R8 spindle' thing.

In *general *it is a very *bad *idea to remove the key. 

Firstly unless you spend $$$ on Hardinge (or better) collets, you can get eccentricity.  With a key you always know which way the eccentricity faces.

Secondly, if you ever overtighten the draw bar, it can be a lifesaver when undoing it.  That's how the set screw can get bend or damaged...  I have experience with this, and on a machine without a set screw.

Thirdly, it is there as part of the fundamental design, and it is shortsighted to remove it unless you understand all the reasons for it being designed into the machine.

so please, unless you are a very experienced machinist, leave it alone!


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## walz10

I’d say your machine is has an R8 spindle. Personally I like most others here wouldn’t worry about the pin. If you want it to be there or it bothers you that it isn’t then by all means replace or repair it. For what it’s worth all the power draw bar installation manuals that I have seen instruct you to remove the pin as part of the installation of the power draw bar. The only warning I’d give you is to make sure that your draw bar threads into whatever you put into the spindle easily. Other than that I think you’ll be fine. 


Sent from my iPhone using Tapatalk


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## r-mm

Guys this mystery persists.  Everything seemed fine using the machine with a drill chuck.  I only today tried it with a 3/8 endmill in a 3/8 R8 collet (double checked both) and the tool spins as soon as it hits work.  Here is what the collet looks like inserted with finger pressure and tightened down with gusto.  

All I can think is to buy a new spindle which Grizley sell for $300.   Presuming this is an import part, does anyone know where else I may look for similar at lower cost?  Other ideas?









						SPINDLE at Grizzly.com
					






					www.grizzly.com


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## Mitch Alsup

When properly tightened, R8 collets just barely protrude beyond the nose of the spindel.
Your collet is significantly below the nose of the spindel.

I suggest getting up inside the spindle to figure out what is going on in there.


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## Dabbler

Mitch is right your drawbar is not pulling the collet up to seating position.


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## higgite

I haven't read this whole thread, but are you sure the drawbar isn't bottoming out in the collet threads? Like too long of a drawbar? Forgive me if you have already checked it out.

Tom


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## tjb

It appears that your collet is not seating properly because it's not being drawn tight enough because the drawbar is too long, as suggested here by others.  You might try putting bushings on the drawbar to see if that makes a difference.  If it does - and it works - you're done.  Or, if you're so inclined, you can purchase a properly sized drawbar.  I had a similar situation once, and bushings fixed the problem.

Regards,
Terry


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## r-mm

I am new to this machine so forgive me if this is a naïve question. If I only thread the draw bar in to the collet a known amount let’s say a half inch then I use the adjusting nut to draw the collet up how would there be a problem bottoming out? 

How can I measure for appropriate fit? 





Perhaps more important if I tap the Collett up into the spindle with a dead blow as such I still cannot get it to seat any further than you see here. I really don’t know what may have happened to the spindle or if someone swapped some thing that is close to an R8 but not an R8.


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## Jim F

Sounds like it is not R8.


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## r-mm

That is my feeling too. Do you all think the grizley is the best option.


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## Jim F

Do you have a borescope you look up the spindle with ?

This is what I have.









						WiFi Borescope - Cal-Van Tools
					

Feature and benefits:   High-resolution, multiple aspect camera (1920x1080, 1280x720, and 640x480) with adjustable LED lighting.  Uses an independent WiFi signal (approximate range is 30 ft.), there’s no need to be connected to a computer.  Mobile app for both Android (2.3 and up) and IOS (6.0...




					cal-vantools.com


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## Jim F

Do you have a piece of say 7/8" stock you could use to measure the inside from the top to the nose of the spindle ?
Maybe something is wedged in the top ?


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## Jim F

r-mm said:


> That is my feeling too. Do you all think the grizley is the best option.


Let do some more looking before we jump to a new spindle.


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## r-mm

Yes i do have a scope ill have a look


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## Jim F

Just for reference, this is holding an R8 in my spindle by hand, no drawbar.


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## erikmannie

I purposely took out the pin in my PM-25MV. It was a set screw. The machine functions the same without the pin as it did with the pin.


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## erikmannie

Shootymacshootface said:


> By what means do you keep the spindle stationary while you tighten the drawbar? Or, do you have a power drawbar?



I know you weren’t asking me, but I use a spindle wrench. I don’t have a power drawbar.




That socket is a 10mm square drain plug (female) socket which fits on the top of my drawbar.


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## r-mm

I am now passed the question of set screw or not.  I can tell it doesn't make a massive difference either way.  I do need to figure out what on earth is going on with this taper.   I charged my boroscope and will check tonight.  I also verified the ring on the bottom comes off easily so I can pull the entire spindle if needs be.   I believe it can now be driven out from the top after the spindle nut is released.


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## brino

Is it just me,
or does the collet stick-out look very different between with draw-bar (from post 38):



and no draw-bar (from post 50):



Was that the same R8  collet?
Of course, one also has a tool in it and the other does not.
Is that the proper collet for the tool? (say both 3/8")

I'm suspicious of it being a Morse taper spindle.
Do you have any MT-2 or MT-3 arbors to try?

-brino


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## Jim F

brino said:


> Is it just me,
> or does the collet stick-out look very different between with draw-bar (from post 38):
> View attachment 350261
> 
> 
> and no draw-bar (from post 50):
> View attachment 350264
> 
> 
> Was that the same R8  collet?
> Of course, one also has a tool in it and the other does not.
> Is that the proper collet for the tool? (say both 3/8")
> 
> I'm suspicious of it being a Morse taper spindle.
> Do you have any MT-2 or MT-3 arbors to try?
> 
> -brino


The second picture is my mill.


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## brino

Jim F said:


> The second picture is my mill.



Ah Crap!
Sorry for littering the thread with my confusion!

-brino


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## Jim F

I think you might be onto something.
The spindle noses do look different.
Maybe it is an MT3.


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## tjb

What about using an inside bore gauge at about the same height of the spindle where it seats, and comparing that to the diameter of the collet?  That might suggest a couple of things:  First, if it's even possible for the R8 collet to seat any deeper.  Second, if there is a taper or a bushing-style stop.

Just a thought.

Regards,
Terry


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## higgite

brino said:


> I'm suspicious of it being a Morse taper spindle.
> Do you have any MT-2 or MT-3 arbors to try?
> 
> 
> Jim F said:
> 
> 
> 
> I think you might be onto something.
> The spindle noses do look different.
> Maybe it is an MT3.
Click to expand...

OP's spindle has a set screw in the side of the spindle. If it was an MT taper, it wouldn't have that set screw, would it?

Tom


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## r-mm

OP : no set screw in my spindle.


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## higgite

r-mm said:


> You are talking about this set screw?   I can remove it and have a look inside if that's what you are referring to. https://www.hobby-machinist.com/attachments/capture-jpg.345894/


Sorry, I must have misinterpreted your earlier post.

Tom


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## Toolmaker51

I'll disagree in re lube on collets. 
Anything likely to retain chips is undesirable. I wipe every spindle taper out and each holder before insertion. A cared for R8 draw bar should literally spin into an equally cared for holder, like that clean ball bearing drill chuck closes on a bit. 

Draw bar is not alone, the thrust washer, the seat it rides, even the hole have to be attended periodically. The unappreciated key becomes the weak link, as when dirt imposes a false sense of tightness, resulting in it shearing or at least burring, making each next change a little more difficult. 
Other misuse occur by holding wrong diameters "it's just a little off" that springs or deforms the collet. All collets have a min/ max tolerance to diameter; only exact diameter initiates cylindrical clamping generated by the taper.  
Only the collets split alternately from each end [such as DA, ER, TG, WW, C series.....] have appreciable deflection to accommodate variance from stated size; not 5C, R8, 215, 2J........... .
Also why those latter collets are proportionally longer, comparing cylinder section to spring section, recovering some grip size flexibility. Never as well as the former, which essentially are cylindrical all the way through. We knew those as 'accommodation' holders, easily identified by distinct dual opposing tapers, though most are two different tapers, simplifying orientation in respective holders. A few can insert correctly either way.

Of the smaller machines, R8 is hugely successful; because the spindle's easily made, just like the collets, making everything more economical, been around f-o-r-e-v-e-r. My horizontal 2B Milwaukee, ~1910, 40 taper has an aftermarket, adjustable R8 swivel milling head from slightly later period. That draw bar not even 4-5 inches long. I'm certain the key is original. I've only seen one other, both clamp the overarm. Sorry, unmarked in brand or patent.

Finally, the real limitation of R8 [our8?] is not support in a spindle of 1.875 in. (48 mm) or quill of 3.375 in. (86 mm); it's tool length per diameter. Large collets have reduced cylindrical sections. Look inside 1/4" 3/8" or 1/2" and then 3/4" or the worst of all 7/8". I'd no more expect to take any kind of material with 7/8" than a minimal squaring up square tube for weldment. Wonder why 3/4" standard double-end endmills are too long for R8? When that's needed, use an endmill holder, setscrew engages the Weldon flat. And you can pull and replace to nearly identical Z height. 

[side note; a shop owner and his cohorts I despise, pronounce it weld-e-mint]. Byword in same place is _'we always did it this way'._
So astute! Not!
Me Judgemental? You bet, I had incredible, astounding, respected mentors.


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## r-mm

brino said:


> Is it just me,
> or does the collet stick-out look very different between with draw-bar (from post 38):
> View attachment 350261
> 
> 
> and no draw-bar (from post 50):
> View attachment 350264
> 
> 
> Was that the same R8 collet?
> Of course, one also has a tool in it and the other does not.
> Is that the proper collet for the tool? (say both 3/8")
> 
> I'm suspicious of it being a Morse taper spindle.
> Do you have any MT-2 or MT-3 arbors to try?
> 
> -brino



I have centers in mt2 (too small) and mt4 (too large). I could buy a cheap mt3 shank to check.


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## Jim F

Just for kicks, try the MT4 in the spindle.
I am going to try a MT3 in my spindle.


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## Shootymacshootface

erikmannie said:


> I know you weren’t asking me, but I use a spindle wrench. I don’t have a power drawbar.
> 
> View attachment 350214
> 
> 
> That socket is a 10mm square drain plug (female) socket which fits on the top of my drawbar.


I see, so your spindle has 2 flats on the bottom for a wrench.


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## ErichKeane

That big set screw near the top of the spindle might just be a bearing oiling port.  I know my millrite has something exactly like that.


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## Jim F

r-mm said:


> I have centers in mt2 (too small) and mt4 (too large). I could buy a cheap mt3 shank to check.


the measurements on your chuck arbor seem to be close to MT4.
Does it have a groove in it ?
An MT3 does not come close in an R8 spindle.


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## Toolmaker51

Discounting possibility of wrong taper, the 1st photo compared to 2nd is missing the thrust washer critical to R8. Tapers of Morse and Brown & Sharpe spindles qualify for milling, all there was in the old days. Most retained by drawbar, located by taper, driving friction aided by taper, compared to tang in a drill press. Not universally though.
Easy way to tell. Flashlight and mirror. Take out drawbar, shine flashlight at side from below, see view in mirror.
Or stick finger in. If you feel a taper end about 3/4 inch in, R8 TYPE collet, because of drawbar. TYPE in caps, due to some proprietary spindles. Continuous taper longer than finger is 'Long taper' of Morse, B&S, Jarno or a couple others. No big deal, first [way more common] two are not rare. Never saw Jarno on a mill.....just lathes and grinders.
Should taper be the case, we'll devise method determining it with you, remote control. Until then, Machinist's Handbook or


			milling machine spindle tapers - Google Search
		


Avoid links to LinkedIn like a plague. Not just COVID variety. lol.  Enough spam and info-piracy going on to make Facebook and most career sites jealous. Posers, armchair experts, witless toads, ad infinitum. Cornucopia if you prefer.


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## erikmannie

Shootymacshootface said:


> I see, so your spindle has 2 flats on the bottom for a wrench.



Yes, it does.


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## Larry$

The photo https://www.hobby-machinist.com/attachments/345873/ shows a threaded opening. Does this lead to a dog type set screw?


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## Jim F

Larry$ said:


> The photo https://www.hobby-machinist.com/attachments/345873/ shows a threaded opening. Does this lead to a dog type set screw?


That is a hole for a pin spanner, to hold the spindle while changing collets.
Atleast on my Grizzly it is.
His seems to be the same spindle quill as a Grizzly, but the spindle seems different.
Looking at the way things fit, I am thinking it is a MT4 spindle bore.


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## Larry$

That then means you have to have the quill down to change collets & tooling?? 
I'm going to guess that's a substitute for a brake? 
Sorry for not knowing this stuff. The only mill I've run has been a BP clone.


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## Toolmaker51

Not familiar with what exact pattern this mill is, and shots are too narrow to ID it.........but R8 needs the spindle up to access drawbar. R8 appears in bench top mill drills, the 3/4 size Rockwells & Clausings, of course standard 12" knee Bridgeport pattern, and the larger version 16" knee. And not much else.
Flats on the spindle nose mean something different. Morse or Brown & Sharpe for milling, a drawbar insures against the cutter helix pulling the sleeve out. Hard for me to envision a knockout 100% reliable milling; drilling naturally is world standard, using the tang as the drive connection.

While a zillion machines had B&S taper, they were horizontals. It was unsuitable for compact designs [ie Bridgeport spindle is restricted by knee] as it is just silly long. Great alignment and drive transmission but not very forward thinking.
Morse, B&S and some others are known as self holding tapers, compared to self releasing like 30, 40 or 50 NMTB [aka NM], or CAT. They need drive lugs on spindle to engage notches on holder. The shape means easy withdrawal, even tilting to avoid obstructions. CAT wouldn't exist without such a feature.

BTW, NM and CAT are almost interchangeable; some CAT are threaded smaller for retention knobs, not matching drawbars, others are.


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## Shootymacshootface

Larry$ said:


> Sorry for not knowing this stuff. The only mill I've run has been a BP clone.


That makes 2 of us!


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## Toolmaker51

I hear that


Larry$ said:


> <snipped>
> Sorry for not knowing this stuff. The only mill I've run has been a BP clone.


and



> That makes 2 of us!



ALL the time. 
Just makes my mentor-mode kick into gear. It's not your fault; when vocational education disappeared, so did exposure to the work what makes the world go 'round. 2-3 generations watch 'How It's Made', Orange County Choppers whatever and think they have a handle on it. Same folks endorse off-shore manufacturing.
WRONG!


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## Jim F




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## r-mm

Mt4 is too large
Mt3 is too small

My scope doesnt love to close focus but the spindle bore looks rough to me. 








I have the gear off at the top (101-103) How should I remove the spindle itself?


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## Jim F

I can not help much, never had one apart, but sleeve (104) needs to come off.
Looks like you need to get to (107) snap-ring.


----------



## r-mm

104 is the part I am most unclear on. I thought it might slide off or move with a few taps from a dead blow but so far I cannot convince it to. I would prefer not to remove the entire quill but maybe I have to.


----------



## Jim F

Maybe pressed into the top bearing.


----------



## r-mm

Guess safest to drop the quill.  Its dumb but the only reason I hesitate is Enco appears to have used body filler and painted over the seam in the side cap 115+154 and I know its gonna chip and look crappy after oh well will do my best.


----------



## Jim F

Better to have it working.


----------



## Larry$

I think you will find that is standard practice on castings. Not just Enco. It's been done since the 1800s.


----------



## r-mm

I know body filler is used.  Did not know removable parts were smoothed over.  New to owning big machines like this however.


----------



## DavidR8

r-mm said:


> I know body filler is used. Did not know removable parts were smoothed over. New to owning big machines like this however.



Before you tear it apart, have you taken any measurements of the inside to see if they approximate an R8 or MT taper? 

Likewise assemble the intended collet and drawbar. Measure from the edge of the taper in the collet to where on the drawbar it would bear on the spindle. Compare that the actual distance from spindle nose to bearing surface on the top of the spindle.


----------



## r-mm

Took it apart


----------



## DavidR8

Any revelations?


----------



## r-mm

Nope. Gonna press the spindle out this wknd.


----------



## DavidR8

r-mm said:


> Nope. Gonna press the spindle out this wknd.


Are you able to better see inside the taper now?


----------



## r-mm

Yes I am but I still do not have a definitive answer. Without a doubt the taper is ugly. It looks as though there was calling and spinning of collects in the past. I gave it a light pass to knock down the high points but still the are eight Collett do not draw in nicely with finger pressure or the drawbar. At this point my two choices are 

1. a new spindle from grizzly for $300. The bearing sizes seem to be the same between the two machines but I have no guarantee it will fit without modification

2. Look for someone to re-grind or repair my spindle. I have no idea whatsoever what this would cost or how difficult it would be. I am not far from Bridgeport Connecticut and there are still a lot of job shops around. 

Any thoughts?


----------



## Jim F

New spindle.
I did not see evidence of the pin, and the R8 collets do not fit the nose.


----------



## ddickey

Grind it yourself in the spindle.


----------



## DavidR8

I have to throw this out there. 

The earlier pics that showed 1/4” of collet protruding from the spindle nose even when drawn up with the drawbar say that something other than a rough spindle taper is at fault here. 

Are the diameters of the collet end of the R8 collet and the interior of the spindle nose similar?
If they aren’t, there’s no way the R8 collet is going to draw up completely. 

Have you tried blueing the inside of the taper and seeing where the R8 collet makes contact?


----------



## Toolmaker51

There are shops specializing in repair grinding of spindles...........even with spindle still in machine. I'm sure taking it in will be less cost than service in place.




__





						shops regringing spindle tapers - Google Search
					





					www.google.com


----------



## ddickey

Are you able to tilt the head and rotate the turret on your machine? If it does you can grind the spindle yourself.
Here's a video that shows the setup.
This shop maybe be able to regrind if you decide to go that route.


			http://millermachineandfabrication.com/contact/te.


----------



## Jim F

Looking at previous photos, that is a lot of grinding, and he still needs to install a pin where there was none.


----------



## r-mm

I just noticed what appears to be an M4 setscrew which is about 3 1/2 inches from the nose of the spindle. It looksmildly staked over is that a feasible location for a locating pin for an R8 Collett?


----------



## r-mm

Pulled the set screw(M4-.75) and it does look to have been sheared off

I


----------



## metric_taper

r-mm said:


> I just noticed what appears to be an M4 setscrew which is about 3 1/2 inches from the nose of the spindle. It looksmildly staked over is that a feasible location for a locating pin for an R8 Collett?


I think if you pull that set screw out, you'll find it is the pin, where it was machined down into a cylinder on its protruding end.


----------



## brino

I was wondering about that from this picture in post #90:



I have no R8 tooling, so cannot speak to set-screw position...

-brino


----------



## Jim F

My pin is not that far up inside the spindle, but it could on yours.


----------



## r-mm

Can anyone tell me what the nose of there R8 spindle is at the widest point? I am seeing right around 30 mm.


----------



## Jim F

Mine is 32mm.
My R8 collets are 31.5 at the end.


----------



## r-mm

Well that confuses me. I was all set to conclude that the pin sheared off and was galled into the bore creating high points and enlarged it but there is no way I can see the nose dimension being so far off


----------



## Jim F

That is what I said before, something is off with that spindle. My R8's sit just under the end of the spindle, without the drawbar installed.


----------



## ddickey

Plenty of meat to grind then.


----------



## r-mm

I was thinking some thing at the back was preventing the Collett from seating. I was debating cutting the rear of a Collett off to see if the taper mates up, taking the rear out of the equation


----------



## Jim F

ddickey said:


> Plenty of meat to grind then.


Maybe at  the end, what about the back ?


----------



## rwm

Here is the inside of my R8 spindle with the draw bar in place.


You can see it has a straight portion at the top, then an unfinished larger ID, then a taper at the bottom. I cannot tell from your original pic if yours looks like this? Can you get a better pic so we can verify it is an R8? It is possible that you have an R8 that is damaged so the collet is not seating properly accounting for the protrusion at the nose?
Robert


----------



## r-mm

It is fairly hard to take photos inside with the clothes focus and darkness. Maybe another way of determining whether or not this is a damaged R8 or some thing else is to ask the question would any other likely candidate have a setscrew? I have ruled out MT2 MT3 MT4 by attempting to fit tapers of those dimension none come even close. I know nothing about Brown and sharp or other obscure tapers does one of them have a set screw?


----------



## brino

I use Brown and Sharpe #7, 9 and (mostly) 11. None have set-screw/key, key-way etc.

For sure there are other collet systems that do.....lemme dig a bit....

-brino


----------



## brino

Check this post by @Uglydog for an attached PDF list of different collet types with dimensions:

https://www.hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/post-313640

-brino


----------



## DavidR8

Jim F said:


> That is what I said before, something is off with that spindle. My R8's sit just under the end of the spindle, without the drawbar installed.



This what I’ve been saying too. 
My hunch is that if the spindle were blued up and a collet inserted, there would only be a circle of blue where the end of the spindle makes contact with the collet.


----------



## ErichKeane

Did you ever use a protractor to measure the angle of the nose?  I presume that might be particularly telling.

It is also possible that it is just a poorly cut spindle, but I'd want to see it blued and measured best we can if possible.


----------



## WobblyHand

Is that a pin sticking out at 6:30 just below the draw bar on post #104?  It looks like it.  Is it above the total length of the R8 collet?  You can just drop a rod into the spindle until it rest on the pin and pull it out and compare with your collet length..


----------



## rwm

Post 104 does not have a pic? If you mean post 109 by me then yes, that is the pin. It engages the collet on the straight part (Zone C). Given that his pin is in a similar location I am thinking that this is an R8 with damage preventing the collet from seating.
I like the idea of a rough measurement of the taper with a protractor. Quick and dirty method: you could also take an impression of the lower taper with plasticine clay and check that against a collet. The angle should be 8.5 on each side or 17 deg total.
Robert


----------



## WobblyHand

rwm said:


> Post 104 does not have a pic? If you mean post 109 by me then yes, that is the pin. It engages the collet on the straight part (Zone C). Given that his pin is in a similar location I am thinking that this is an R8 with damage preventing the collet from seating.
> I like the idea of a rough measurement of the taper with a protractor. Quick and dirty method: you could also take an impression of the lower taper with plasticine clay and check that against a collet. The angle should be 8.5 on each side or 17 deg total.
> Robert


My bad on miscounting posts.  I thought you had posted you had removed the set screw which was sheared.  Is this the replacement set screw?  Does your collet slot engage this pin?  Sorry for the primitive questions.

Measuring the taper of both the spindle and your collet is a very good idea!

If you remove the drawbar and insert a rod of the diameter of slightly less than the collet backside diameter (to avoid engaging the pin) how far does it go in compared to the collet length?  

Crazy idea, can you make a rubber (or rubber like) impression of the insides?  Don't know exactly how to do this, but isn't the issue basically checking all these internal spindle dimensions as compared to a _known good_ R8 collet?


----------



## higgite

Wobbly, I think you’re afflicted with the same malady as me. I was confusing rwm with r-mm until I finally noticed that rwm’s spindle pic didn’t match r-mm’s pics.  

General question, does it seem to others that the sheared set screw in r-mm’s spindle is awfully far up in the spindle for an R8 guide pin/screw? I have a bench mill, not a knee mill, but like Jim F, the guide pin/screw isn’t nearly 3-1/2” from the end of the spindle. Mine is more like 1-5/8”. Is it common for the pin to be recessed as far in as r-mm's on, say, a Bridgeport or similar spindle?

Tom


----------



## ErichKeane

My pin is pretty low as well, that one is shockingly high! I'm unsurprised that it is sheered off, it looks like you could engage the drawbar before hitting the pin!


----------



## higgite

ErichKeane said:


> My pin is pretty low as well, that one is shockingly high! I'm unsurprised that it is sheered off, it looks like you could engage the drawbar before hitting the pin!


True! I hadn't even thought of that. Could that be how it got sheared?

Tom


----------



## higgite

r-mm said:


> Pulled the set screw(M4-.75) and it does look to have been sheared off
> 
> I
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 351490


Did you try the collet for fit with the set screw removed?

Tom


----------



## ErichKeane

higgite said:


> True! I hadn't even thought of that. Could that be how it got sheared?
> 
> Tom



I'd put money on it.  Not a lot, but money


----------



## WobblyHand

higgite said:


> Wobbly, I think you’re afflicted with the same malady as me. I was confusing rwm with r-mm until I finally noticed that rwm’s spindle pic didn’t match r-mm’s pics.
> 
> General question, does it seem to others that the sheared set screw in r-mm’s spindle is awfully far up in the spindle for an R8 guide pin/screw? I have a bench mill, not a knee mill, but like Jim F, the guide pin/screw isn’t nearly 3-1/2” from the end of the spindle. Mine is more like 1-5/8”. Is it common for the pin to be recessed as far in as r-mm's on, say, a Bridgeport or similar spindle?
> 
> Tom


Well @higgite thanks for being kind about it!  Now I need to go back in the thread and figure out which pics belong to the OP...  

Nonetheless, a rubber impression like casting might further identify what the issue is.  Or use a 0.75" rod which should always fit and see if it goes into the spindle cavity at least 4".  And measure the taper.  Maybe just use a wad of modeling clay and press it in and compare with your R8 taper. Oh, please check that what you think is an R8 actually is one.


----------



## DavidR8

The dimensions of the drill chuck arbor in post 28 look pretty darn close to the dimensions for an R8 according to that drawing. 
At 29.9mm/1.18” the nose of the spindle is not sized for an R8 collet. 
It has to be a different taper.


----------



## WobblyHand

To get the clay out mostly intact, I'd use some all thread, a washer and a couple of nuts to hold the washer.  Size the washer around 3/4" OD.  Slightly oil the inside of the spindle to act as a release agent.  Put the washer assembly in about 1.5".  Sort of hold the all thread centered and pack clay in around the rod to fill the cavity.  Might have to make a simple spider to get it roughly centered.  When packed full of clay, pull the rod out of the spindle and you should get a decent impression of the inside of the spindle.


----------



## WobblyHand

DavidR8 said:


> The dimensions of the drill chuck arbor in post 28 look pretty darn close to the dimensions for an R8 according to that drawing.
> At 29.9mm/1.18” the nose of the spindle is not sized for an R8 collet.
> It has to be a different taper.


Although the two in the picture are similar, they aren't the same at all.  I can tell from the picture that the arbor taper is longer than the R8 taper.  My eyes aren't good enough to estimate the taper angle.  My R8 looks exactly like the one on the left, and is really close to the drawing.  I'd bet the taper angles of the spindle and the R8 are different.  That might account for the R8 not going in as far as it should.  Only way to know is to measure it somehow.

If the clay method isn't suitable, one could cut off the back of a collet (so there's no interference due to length possible) and blue the collet taper. Then push into the spindle.  It will be very obvious if the tapers are different.  Shoot, why bother.  Just blue the R8 now and see what transfers.


----------



## ErichKeane

I see two different situations that may have happened:
1- It is actually an R8 spindle that is just somewhat poorly made and designed.  There isn't really a 'standard' for R8, so I could see a cheap importer just putting the pin were it was easy to fit/machine, and not cutting the taper deep enough.

2-It is some oddball taper that is close enough to an R8 to be reasonably effective with an R8 collet in it.  The previous owner, thinking it was R8, used R8 tooling (including that drill chuck!) with it.

I'd guess #1.


----------



## rwm

I didn't see the similarity in the names!
The pin in my R8 spindle is 3.1" from the nose and engages the straight part of the collet. 
Robert


----------



## WobblyHand

rwm said:


> I didn't see the similarity in the names!
> The pin in my R8 spindle is 3.1" from the nose and engages the straight part of the collet.
> Robert


The pin really could be just about anywhere along the slot, so that seems ok.


----------



## WobblyHand

On my collet, the length of the taper is 1.038". That's the length along the surface.  Can you measure the length along the surface of the spindle taper?  According to the drawing above, it should be r = 1.015"/cos(8.25) = 1.026" minimum.  

If you put a ground rod against the spindle bore, and measure the distance from the rod to the edge of the spindle taper, what is that dimension (y)?  If we know both y and r, then the angle of the taper is arcsin(y/r).  If you have the correct taper it will be 8.25 degrees.  If r isn't long enough, you know the spindle taper wasn't bored fully.  If you have measured this already, my apologies.


----------



## r-mm

Thanks for all the ideas folks I haven't forgotten about any of them but have yet to find time for the protractor / prussian blue check on the spindle.  

I did try quickly knocking down high points with a light filing and fully removing the sheared off setscrew and got the same results as before.


----------



## rwm

I'm still dying to know the answer!
R


----------



## r-mm

I blued the inside of the spindle bore and set an R8call it by hand then gave it a few taps with a dead blow. It certainly does not look to make very nice contact.


----------



## DavidR8

Is that two sides of the same insertion?
Looks like the one side is making ok contact but the other side is barely touching at all. That doesn’t make any sense if it’s concentric.
If you have a set of bore gauges it would be good to measure the bore at the top of the taper and at the nose. 
That would give you a rough approximation of the size which you could compare to the R8 taper spec. 

I think I recall that you tried MT tapers right?


----------



## ddickey

Did you have a pin or endmill in there?


----------



## higgite

r-mm said:


> I blued the inside of the spindle bore and set an R8call it by hand then gave it a few taps with a dead blow. It certainly does not look to make very nice contact.


I would suggest that you use the drawbar for the bluing test in order to get straighter seating of the collet in the spindle.

Tom


----------



## r-mm

There is no end mill in the Collett for the test. I can redo it using the drawbar


----------



## ddickey

You should have an endmill in the collet


----------



## r-mm

Grizzly was kind enough to send me photos of the replacement spindle they sell. I’ve already checked that the bearing sizes and spanner nut match those from my Enco. The only difference I can see between my spindle and the replacement is that it appears the base of the drive splines are threaded on the replacement?

The photos with the bearing still attached are my existing spindle


----------



## ErichKeane

Is there another bearing they goes there that used a bit there for preload?


----------



## r-mm

Yes the shoulder at the bottom of the splines is 30 mm and is a light interference fit to the ID of the bearing at the top of the quill. I cannot see a nut in the grizzly diagram nor my mill that would provide pre-load.


----------



## DavidR8

Isn't part #126 the preload nut in the diagram?


----------



## rwm

If you choose to replace the spindle, it is imperative that you send the original to an experienced member for forensic analysis. 
Robert


----------



## r-mm

126 is the 35mm nut that loads the bottom two angular contact bearings. Both spindles appear to have the same nut.


----------



## r-mm

Here is the Prussian blue test with a tool installed in the Collett and the drawbar used

Because it is making reasonably good contact where it has been drawn into the spindle I am now wondering if the taper is correct but the remains of the setscrew significantly damaged the rear of the bore which is preventing the Collett from going further in. The quick and dumb way to test this would be for me to cut the back off a collet to see if I can push it in by hand


----------



## rwm

I think you are probably correct. Now that the spindle is out, can you better see the deep part of the taper? You could make a plug that matches the dimension of the collet and see if it fits. Kind of like a Go gauge.
Robert


----------



## r-mm

I cleaned up the inside of the bore using small flap discs. This definitely helps all of the collets but still I find that and on modified Collett will only draw in maybe a half turn of the nut before it feels like it is bottoming out. I tried removing the small shoulder on the rear - that is the photo in the middle. I get the same result. It is only when I remove some of the length of the collet - on the left - that I can get the drawbar nut to make a few rotations feel it moving in and see the Collett closing down. 

I think I may get some more flap discs and continue this effort.


----------



## r-mm

rwm said:


> I think you are probably correct. Now that the spindle is out, can you better see the deep part of the taper? You could make a plug that matches the dimension of the collet and see if it fits. Kind of like a Go gauge.
> Robert



I made that plug gauge and it tells me the last 5-6mm do not want to seat


----------



## DavidR8

So that would seem to indicate that the bore is not deep enough to take the full length of an R8 collet. 
Or is boring the spindle an option?
Is cutting your collet to length an option?
(Totally spitballing ideas here...)


----------



## r-mm

All options.  I'm going to have a look with my dial bore gauge to see if I can understand whats doing on better.  

Does the rear of the collet contribute to concentricity or can I hog out the spindle bore with the flap discs?  

I don't have a boring bar long enough to clean the bore on the lathe but suppose I could change that...


----------



## DavidR8

I think concentricity is determined by the taper. But that's just my guess. 
Did the mill come with any collets?


----------



## Ken226

The concentricity is determined by the taper, but unlike Morse tapers, the R8 has a rather short tapered section.  The upper portion of the collet maintains alignment, preventing radial forces on the end-mill from acting as a lever, altering alignment.

Even short collets like ER32  have a longer tapered section than R8. (1.57") for ER32
Vs the tapered section of an R8 (.95")



Without the support of the upper portion of the collet, you can expect more deflection of end-mills under heavier loads.  Also, you'd be relying on the tension of the drawbar, and concentricity of the drawbar/collet threads to prevent movement.  

The collet threads may not be very concentric to begin with, as the manufacturer never expected those threads to be used to aid in alignment. 

If you can chuck up a cut off collet, it would be interesting to see how much runout is indicated at several points along a drill rod.

Anything worth doing, is worth doing right.  Replace the spindle, or send it out to be reground.


----------



## Ken226

BTW,  pics of your spindle show what looks like deep groove radial ball bearings, which probably suck for a mill spindle. That's likely why there are no threads. Nothing to pre-load.

I think the reason the grizzly replacement is has those threads at the bottom of the splines, is because it is an updated version of yours, designed for tapered roller or AC bearings.    That threaded portion is likely for the preload spanner nut/nuts that are needed for the preload adjustment of tapered rollers and/or angular contact bearings.

If...   well, when..., you replace the spindle, you'll also be doing a worthwhile upgrade, because you'll need a set of tapered roller or angular contact bearings and the preload nuts as well.   You may as well order the bearings and preload nuts from Grizzly when you rebuild the spindle, they'll be necessary.

Here is the one piece preload nut from my G0704 CNC build.  The 2 cap screws lock the nut onto the threads.

The 2 empty holes are for a pin wrench.




I used Abec7 rated bearings from NSK in this spindle.  It has less than .0001" of radial runout measured in the spindle taper.

If your on a budget, I believe Nachi has some p4 precision angular contact bearings for under 100$ a set.

Do your own research though. I can't be certain they aren't knockoffs or something.  Since your mill doesn't run much over 2500rpm, I think the polyamide cage would likely be fine.  Polyamide melts at about 450°f.  My CNC spindle runs 8000rpm, and doesn't get anywhere near that hot.





__





						Nachi Japan 7207 CYUGL P4 Super Precision Angular Contact Ball Bearing: Amazon.com: Industrial & Scientific
					

Nachi Japan 7207 CYUGL P4 Super Precision Angular Contact Ball Bearing: Amazon.com: Industrial & Scientific



					www.amazon.com


----------



## r-mm

To the best of my ability it seems the bearings on my current spindle and listed in the G0731 parts manual are the same


----------



## r-mm

I think I can set up to bore the spindle. Just need a longer boring bar.


----------



## Ken226

r-mm said:


> To the best of my ability it seems the bearings on my current spindle and listed in the G0731 parts manual are the same


Yes.  7207 is 35x72x17mm.    A fairly common size.  Available on amazon from 15$ per set, to 2000$ per set, depending on precision rating.

P4 is equivalent to Abec7.   .00015" runout or better, if I remember correctly.


----------



## rwm

I'm worried a boring bar long enough to cut the tail end of the R8 taper will chatter like my ex wife. I suppose a 1" bar might work?
Robert


----------



## Ken226

r-mm said:


> I think I can set up to bore the spindle. Just need a longer boring bar.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 354395



Not likely.  The spindle is almost certainly hardened..  you might be able to cut it with carbide inserts,  but in a 3 jaw, you'll very likely cut some axial runout into your new taper.  Probably way more than a spindle should have.

If your going to try it yourself (nothing to lose at this point) anyway.   Best way would be to put it back together, and rig a toolpost grinder onto your mill table.  Grind it in-place, in your mill.

At worst,  remove the bearings and use a 4 jaw and steady rest, and a toolpost grinder. (You can try a boring bar. At this point, you got nothing to lose, but expect trouble).  

  Indicate to the nth degree,  off of both bearing journals.  Get it indicated to .0001" or better,  off both bearing journals, to get rid of all axial and radial runout before touching the taper.  

Both of the spindles internal collet bearing surfaces, the taper and the upper portion, need to rotate co-axially with the bearing journals, and with as little radial runout as possible.   If you were to send it to a pro shop to be re-ground, most will hold it to a .0001" or less standard.

Personally, I'd replace it and buy good bearings.   In a year, you'll be proud of the precision work you can do and won't even miss the money..


----------



## r-mm

To be clear i am not attempting to cut anything to do with the taper. I am only attempting to fix what I presume is galling and scoring at the rear which is preventing a non-shortened collett from being drawn tight.


----------



## Ken226

r-mm said:


> To be clear i am not attempting to cut anything to do with the taper. I am only attempting to fix what I presume is galling and scoring at the rear which is preventing a non-shortened collett from being drawn tight.



Pull the bearings.  A bearing puller is like 15$ at harbor freight.   Chuck up the in a 4 jaw, with a steady rest for support.

Get 2 indicators on the bearing journals, and dial them in untill the needles don't even twitch.

Then take the lightest cut possible with your boring bar, test fitting a collet between passes.

A cut that light won't require a 1" boring bar, but if you can get one, it'll surely help.

Your taking a tiny cut, just knocking down the high spots that arose when whatever disaster caused this, occured.


----------



## DavidR8

My opinion is that the spindle the spindle is not bored deep enough to the diameter of the R8 collet shank.
Based on the photo of the test plug I don't think it's burrs that are preventing full insertion. It's simply not the correct diameter, deep enough to take the collet.

Did the mill come with the collets that don't fit or are those new?


----------



## r-mm

I have several bearing pullers and a hydr press these come off the long end and Ive been having a hard time setting up to get them off


----------



## Ken226

Just to clarify,  I realize your wanting to recut the upper portion. Not the taper.

The upper portion is a precision bearing surface as well.  It needs to be cut concentric and co-axial to the spindle taper.    

Ideally, to no more that a ten thousandth.  Your spindle should be at least as accurate as the bearings.


----------



## Ken226

r-mm said:


> I have several bearing pullers and a hydr press these come off the long end and Ive been having a hard time setting up to get them off




Bearings can be a pain to remove on long spindles.

Most like yours, I've removed by having a helper hold the spindle upside down on an aluminum block, and using a section of pvc pipe over the spindle nose, against the outer race.  Hammering it off with a mallet.

I don't reuse bearings after removal.  Replacements are cheap and plentiful.

I've been using the same thick walled PVC pipe sections for 10 years.   About 4$ ea at ace hardware.

If you take the spindle and quill sleeve with you to the hardware store, it's easy to find some pvc sections of the appropriate diameter for reinstalling new bearings.    Just put all the forces on the inner race for shafts, and the outer race for bores.  Don't transfer forces through the rolling elements to avoid the risk if brinelling.


----------



## r-mm

Appreciate all that advice.  This is my first mill and I don't mind a little work to see if the spindle is salvageable.  Chances are I may get some better collets and end mills once I get the hang of things so I view this as semi-sacrificial startup stuff.  I ordered a larger tool holder and will get a 5/8 carbide boring bar and see if I can clean the inside on the lathe, with the bearings removed. 

A question regarding hardening - how deep into the metal does it go?  I already removed the ugliest high spots with the alum oxide flap disc.   Is the metal hard "all the way down" ?


----------



## ddickey

You should really do this on the mill. Make a block for your boring bar. Put it in the vise straight up and have at it. You can set your depth with the quill lock. 
Just an idea.


----------



## r-mm

ummm....  about that mill.... and its lack of... spindle?


----------



## ddickey

Put the spindle back in.


----------



## Ken226

It is most likely made from a pre hardened steel.  So, it would be through hardened.

   A spindle would be hardened first, and ground after, to minimize the effects of the heat treat causing dimensional changes.

I doubt that is an extremely hard steel, but tough and hard nonetheless.   Take light cuts with sharp insert and you'll probably be fine.  Maybe something like a tcgt non-ferous style insert.  They are very sharp and make light cuts at low speeds a breeze.


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## brino

r-mm said:


> ummm.... about that mill.... and its lack of... spindle?



It's really using the mill like a lathe and turning the ID of the mill spindle in place.
You reinstall the spindle, spin the work-piece (the spindle) and move the tool with the table X or Y-axis lead screws.
The boring bar is held in a block that is bolted to the table and is pointing straight up inside the spindle.

-brino


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## Ken226

ddickey said:


> You should really do this on the mill. Make a block for your boring bar. Put it in the vise straight up and have at it. You can set your depth with the quill lock.
> Just an idea.



This would be my first advice as well, with 1 caveat.    

If it has junk bearings, milling it in place will permanently machine those junk bearings runout into the spindle.   After that happens, you'll never have an accurate spindle again, regardless of how much you spend on bearings. 

He can't put good angular contact bearings on that spindle, because it lacks the preload threads.  

My opinion:  experiment all you want with repairing this spindle, because in the end,  you almost certainly be replacing it anyway.


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## ddickey

Since you're not touching the taper the spindle can be placed in a vertical position. 
Here a video of turning on the mill.


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## ddickey

I had a round column Grizzly like that and replaced all the bearings in it. Unfortunately I can't remember if I had those threads.


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## Ken226

There are precision AC, no-preload bearings available in that size, but they are for predominantly axial loads. Probably not the best idea for a mill spindle.  Of course, neither would deep groove radial bearings, but that appears to be what it has.


For a low rpm knee mill (under 3000rpm) that may see both  heavy radial and axial loads from operations such as using boring heads,  and drilling,  tapered roller bearings are probably best.

Tapered rollers in that size would be 30207.   NTN makes them, 100$ ea on Amazon in P5 precision.      They are 1.25mm thicker, but I don't think that would be an issue, as the Griz spindle has plenty of threads to accommodate the 2.5mm overall difference.



			Amazon.com
		


Here are the tapered rollers from NTN.




__





						30207P5 - NTN - Precision - Factory New: Amazon.com: Industrial & Scientific
					

30207P5 - NTN - Precision - Factory New: Amazon.com: Industrial & Scientific



					www.amazon.com
				




The last 2 of this type knee mill I worked on both had tapered roller bearings. One was a G0730 and the other was a Taiwan made version from KBC tools.


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## Shootymacshootface

After loosing track of this thread because, for some reason I stopped getting notifications for it, I just read the last 3 pages and have these thoughts.
Is there such a thing as an R8 reamer?
Why not make one of the popular ER collet attachments work there, if you could live with its limitations.
How did the previous owner use this thing?

Sorry if any of this has been discussed already.


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## Ken226

These things are all copies of the old Clausing 8000 series mini knee mills, like the Clausing 8250.   I believe back in the day, they were referred to as the "wood mill".





I used to own the version KBC tools sold, with ugly baby blue paint.   It had the same threaded type spindle as the Griz version, with cheap Chinese p6  tapered rollers.  The guy I sold it to got a smokin deal.  The NSK P5 tapered rollers I installed after I bought it cost about half what I paid for the thing.


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## r-mm

Okay I got it.  I have 5C collet blocks, are those appropriate for this operation?


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## Ken226

I'm not sure.  What do you have in mind with the 5c collet blocks?   

For holding the boring bar in a vise, and boring the spindle in-place on the mill?

If so, then yea, that would probably work as well as anything for holding the boring bar vertically.

Take off as little as possible.


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## r-mm

Yes sorry I intended to quote Brinos post describing the operation but apparently failed


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## r-mm

Here is a long boring bar in a 5c collet block. 

Now I need to replace the bearings and have at.


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## DavidR8

r-mm said:


> Here is a long boring bar in a 5c collet block.
> 
> Now I need to replace the bearings and have at.
> 
> View attachment 355289


Looks good though you will want to keep the tool stick out to just what is necessary to perform the operation.


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## rwm

I gotta think that boring bar is too long and too narrow for this operation.
R


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## Ken226

It'll have to be long enough to reach the top of the upper register in his R8 spindle.

That is to say, he will need 4" of boring bar to reach the top.  About 4-1/4" ish, to keep the collet block from rubbing the spindle nose.

He shouldn't need to take much, if any, depth of cut.  Just knock down any high spots from whatever damage is there.

With 4.25" of stickem-out and light cuts, he'll probably be ok.


Most likely, someone in this machines past under-tighted an end-mill holder,  sheared the index pin, and kept a pushin while the holder was galling out the spindle.


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## DavidR8

Based on the photos of collets that were modified I don’t think the problem is damage. I think the internal bore is not large enough, far enough up the spindle.


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## r-mm

Hi all.  Here's a photo mocking the boring bar up, positioned to the rearmost surface that needs material removed.  Yes I will fine tune stick out when I'm ready.


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## r-mm

Regarding the bearing replacement - McMaster has good options for all besides the two angular contact bearings at the bottom of the spindle.  









						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com
				











						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com
				




The angular contact bearings are 7207b.  I removed the old ones which are Made in Japan NSK brand and look/feel to be in good condition.   Mcmaster lists 7207 for $86 each.  https://www.mcmaster.com/6680K18/

This is my first hobby machine and I do not want to spend a huge amount on bearings.  I do realize their importance, but everything is a balance.  I want to get to know the machine, make some parts - which I never have - and see how I feel from there.


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## DavidR8

r-mm said:


> Regarding the bearing replacement - McMaster has good options for all besides the two angular contact bearings at the bottom of the spindle.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> McMaster-Carr
> 
> 
> McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
> 
> 
> 
> 
> www.mcmaster.com
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> McMaster-Carr
> 
> 
> McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
> 
> 
> 
> 
> www.mcmaster.com
> 
> 
> 
> 
> 
> The angular contact bearings are 7207b.  I removed the old ones which are Made in Japan NSK brand and look/feel to be in good condition.   Mcmaster lists 7207 for $86 each.  https://www.mcmaster.com/6680K18/
> 
> This is my first hobby machine and I do not want to spend a huge amount on bearings.  I do realize their importance, but everything is a balance.  I want to get to know the machine, make some parts - which I never have - and see how I feel from there.


You may want to check out Bearings Canada. I picked up Nachi angular contact bearings fro my mill for less than expected.








						2 Bearing 7207B 35x72x17 Angular Contact
					

2 Bearing 7207B 35x72x17 Angular Contact



					www.bearingscanada.com


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## Ken226

How is the spindle end-play and preload for AC bearings set or controlled on that spindle?  It didn't have threads nor an adjustment nut, right?

Ha!  Nevermind.  I see the threads in your pic.

The cheapest precision bearings I can find are abec4 7207 on Amazon for about 86$ each.

Just get the best you can afford. Having a thousandth of spindle runout is better than not having a mill.  If that means 20$ truck axle bearings, it's still better than no mill at all.


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## r-mm

I see well priced Nachi bearings on ebay then questioned if they may be counterfit.  The price on Bearings Canada suggests maybe not - but I don't see anywhere on the link posted that those are in fact made in japan. 









						7207 B Nachi Angular Contact Bearing Made in Japan / SAME DAY SHIPPING !!!  | eBay
					

These bearings are non-separable. Since the balls are inserted utilizing counter-bore construction, a larger number of balls can be installed than in the case of Deep-groove ball bearings. Standard cage materials may be pressed steel, high-strength brass, or synthetic resin.



					www.ebay.com


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## DavidR8

r-mm said:


> I see well priced Nachi bearings on ebay then questioned if they may be counterfit.  The price on Bearings Canada suggests maybe not - but I don't see anywhere on the link posted that those are in fact made in japan.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 7207 B Nachi Angular Contact Bearing Made in Japan / SAME DAY SHIPPING !!!  | eBay
> 
> 
> These bearings are non-separable. Since the balls are inserted utilizing counter-bore construction, a larger number of balls can be installed than in the case of Deep-groove ball bearings. Standard cage materials may be pressed steel, high-strength brass, or synthetic resin.
> 
> 
> 
> www.ebay.com


The ones I linked to are not Nachi, but they do have several varieties of Nachi 7207.




__





						Search Results, Bearings Canada, The Ball Bearing Canadian Online Store
					





					www.bearingscanada.com


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## r-mm

Got it thanks.  Similar prices (pre US shipping) as the auction I found.


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## Ken226

The price will have less to do with brand than with precision level.   Nachi makes 20$ bearings and 1000$ bearings in the same size.  So do all of the other manufacturers.

They all have factories in Japan, China, the US and many other countries.   As long as it's a reputable manufacturer, it doesn't matter so much which manufacturer it is.

Choose the precision level your willing to pay for, then worry about the brand.   FAG, NSK, Timken, SKF, Nachi all produce everything from the bearings in your blender, to the turbine bearings in a Leer45.


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## Ken226

@r-mm 

Since budget is a concern, For the best bang for the buck, check out the FAG X-life line if bearings

They have a reputation for very often testing way better than their precision rating level in radial runout.





__





						7207-B-XL-TVP FAG • SP
					

Buy 7207-B-XL-TVP manufactured by FAG. Height: 17, Inner Diameter: 35, Outer Diameter: 72, Weight: 282.  a.k.a. 7207-BE-P (SKF),7207-B-TVP (FAG).




					www.sp-spareparts.com


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## r-mm

Thanks for the tip.  I'll see if I can locate those domestically.


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## r-mm

There is a spacer between the two angular contact bearings. I cannot recall how these were when I dismantled them should they be pressed together so that the spacer is tight between the two bearings?


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## Ken226

Yes, that's the only thing that would make sense.   If there were any space between the spacer and outer races, an outer race could slip, and your inner race would lose its preload.

Make sure you put the new bearings in the correct direction.


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## Ken226

I believe that in a spindle configuration like yours,  the "back to back" configuration is correct.

The spacer gives them the correct seperation distance.  

The back-to-back configurations means that axial forces acting upward on the spindle, such as drilling, puts the axial load on the lower bearing.

A force pulling downward on the spindle, would put the axial load on the upper bearing.





You can see how the axial forces would be transmitted at an angle from the inner race, through the rollers, into the outer race, by the shape of the raceways.


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## r-mm

Thanks guys. I have new bearings here and a press with larger working distance coming this week.


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## mikey

Just a couple of comments, r-mm.

If you can get a new spindle with a* known* R8 configuration then that would be the best way to go. Given how important an accurate spindle taper is, why mess with boring or home-grinding it?
You packed the bearings in post 195 with waay too much grease. Spindle bearings only require 25-30% of the bearing be packed with grease. During run in, the grease will distribute properly. Over greasing bearings will make them run too hot and may lead to premature failure.
I understand trying to save money but given that an accurate spindle will improve tool life, accuracy and finishes, it is poor economy to go with a wonky spindle and cheap bearings.


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## r-mm

Well that only took the purchase of a new press ha. Old bearings off, new ones will go on. 

Can anyone tell me how I set the preload with the ring nut? eg: how much is enough?




Do I need to pack these (less full) with grease?
	

		
			
		

		
	

View attachment 358237


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## Tozguy

Nice press, now we're hummin'


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## MrWhoopee

Always good to have an excuse to buy more tools.


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## Ken226

r-mm said:


> Well that only took the purchase of a new press ha. Old bearings off, new ones will go on.
> 
> Can anyone tell me how I set the preload with the ring nut? eg: how much is enough?
> 
> View attachment 358236
> 
> 
> Do I need to pack these (less full) with grease?
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 358237



It's generally done by temperature.  A setting that results in the bearings warming up after 30 minutes and fill speed, but not too hot too hold your hand on.       For mine,  I like it to reach about 130-140f after 30 minutes of use.

That said,  unlike a lathe, these preload nuts are a pain to be adjusting multiple times, on the fly.

For my cnc mill,  I went as tight as I could get the nut with my bare hands,  then picked a spot on the outside edge of the nut and tapped it about another 1/16” in the tightening direction.

After 30 minutes @4000 rpm, it was at 130°.   I could have got a little tighter, but runout was under a ten thousandth, so I left it alone.


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## Ischgl99

You’ve gotten a lot of great advice here.  One more thing to check is the spacer.  It needs to be flat and parallel to 0.0001” otherwise the bearings might not remain parallel and maintain the proper preload.

If you decide to get your spindle checked out, there is company up here in New Milford called Cavco that rebuilds machine tools and would be able to bring it back to specs.  I have no idea how much that would cost, but an option for you.


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## rwm

I am confused about the spacer. I always thought spindle bearing had to be "matched ground". My understanding was that once matched, they would be correctly preloaded if they were placed face to face without any spacer? In this application it seems like the spacer will hold the inner races apart and preload would be established by tightening the nut which pushes on the inner races? That seems unreliable at best. It works well for bicycle headsets! Am I interpreting this correctly? Would it be better to use a matched ground set? I have never built a spindle but please enlighten us if you have experience. 
See this:





						Duplex bearings | Principle Engineering
					

Duplex Bearings provide accurate alignment in both radial and axial directions. Vibration can be eliminated and higher load capacity achieved.




					principle-eng.co.uk
				



Robert


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## Ischgl99

A matched ground set is only needed when the bearings are mounted without a spacer between them, or a spacer on the inner AND outer rings.  You would need to order them with the preload you want, light, medium, heavy, etc.

The way these mills are designed, the bearings are spaced apart to increase the rigidity of the spindle, it also helps with heat dissipation.  The spacer provides the spacing between the bearings on the outer ring, as well as keeping them parallel.  You can adjust how much preload you want by how tight you make the nut against the top bearing inner ring.  If there was a spacer on the inner ring as well, it would either have to be precision ground to the amount of preload you wanted for the bearing set, and then you would just tighten it down until it stops and not worry about adjustment, or you would have both spacers the same height but use bearings with the appropriate preload ground into the rings.  It’s a lot cheaper to do it with a single spacer and manually adjust the correct preload.


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## rwm

Thanks for the reply. That now makes sense to me! I suppose if I ever build a spindle I would go the matched ground route just to keep it simple.
Robert


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## r-mm

Hey everyone after focusing on some other projects I finally got my spindle and quill assembled and ready to install back into the head. 





I am presently stumped by two things. First is that the quail absolutely will not start at the bore on the head. I gave the edge a light deburring on both parts but it still will not budge. What is odd is that I can get it started upside down. Are parts like this is known to be a tight fit that requires heating and cooling and light press action possibly from the knee?





The other thing is that it looks like the male splines on the spindle are slightly crowned meaning they are wider at the very end. I do not have enough experience to know if this is damage or intentional but they will need to mate with the female splines while I am inserting the quill. 

I


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## metric_taper

The spindle outer bore should fit tight, if you can start it from the top, then it too was mushroomed by a hammer.
That spline damage looks like hammer damage. That should be filed to the same diameter as the rest of the shaft.


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## r-mm

I pulled the spindle and bearings to check if the top bearing was out of spec and pushing the bore out. The bearings (new old) measure the same but without a doubt the quill OD is larger at the offending end by about .1mm


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## Toolmaker51

Won't get reliable measure with a caliper. Also unlikely undersize per se, more that is burnished from riding in quill housing, not all have hard chrome plating. That will affect bore AND quill diameter riding through opening, at variance to what never exits. The tolerance/ allowance between them is not 'tight' by definition, it's minimum clearance with remainder taken up by lubricant. Mill spindles are sized to hold sufficient bearing size, and a lot of surface area to the housing.
It's why milling is best best performed with retracted quill. It's why drill presses make crappy milling machines. 
Spindle or quill, never ran into a knee mill needing heat. Since they haven't built-in cooling, those tolerances would not result in a sweet running machine.
I doubt 3 of a hundred people can insert a quill free hand, maintaining _perfect axial alignment. _Cup the lower end in a short, faced off, section of tube on  piece of printer or wax paper right on the mill table. Use both axis to 'find' centerline and raise carefully with the knee, twisting paper if need be. Until spindle has entered housing, roughly equivalent to one diameter, there really is little assurance of correctness. ie, 10% in = 90% probability of misalignment, halfway in is 30 to 50% and so on. Entirely dependent on physical sizes involved. Some might freeze spindle.....and risk condensation in non soluble lubricant, Sticky as hell, no lubrication. 
It is possible towards the end to have problem when lower bearing retainer enters; dirt in mating faces, retainer over tightened, set screw protruding or too tight, incorrect bearing fit to bore, among others.


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## rwm

Which way did you pull the quill out? Are you saying you can't reverse the process now? It has to fit, unless you are mis-aligned as Toolmaker suggests.
Robert


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