# Strange R8 Collet Problem.



## rdsii64 (Apr 23, 2015)

I have a very weird problem with my mill. When ever I have to remove or reinstall my R8 shank drill chuck, it goes off with out a hitch.  All I have to do is lossen the draw bar a half turn,  give a light tap with a hammer or rubber mallet, then back out the draw bar and easy peasy its done. I actually have to hold my hand under it to catch it when it falls out. Its that easy.

My R8 collets are another affair. Installing a removing an R8 is such a fight I have actually galled the threads on my draw bar and had to replace it.  Inf fact I actually have to tap the collet up into the spindal so the draw bar can thread into it.  I know this can't be right I just don't why, nore how to fix it.

If it will help figure out the problem, my mill is your typical bench top X2  mini mill with an air spring and belt drive conversion.

I have considered just going to end mill holders and swearing off collets for good but I'm not sure I won't hve this issue with an end mill holder.

Please advise


----------



## darkzero (Apr 23, 2015)

This is worth checking out:

http://www.fignoggle.com/machines/r...t-problems-not-all-collets-are-made-equal.htm

http://www.fignoggle.com/machines/r...-R8-spindle-collet-fitment-problem-solved.htm

Or try a higher quality brand of collets.


----------



## chips&more (Apr 23, 2015)

Check the threads on the draw bar. Chase all the threaded holes in the collets. Check the keyway pin for correctness. Check the collets for burrs. That should do it…Good Luck, Dave.


----------



## darkzero (Apr 23, 2015)

chips&more said:


> Check the keyway pin for correctness.


Or better yet, take that stupid thing out!


----------



## rdsii64 (Apr 23, 2015)

darkzero said:


> This is worth checking out:
> 
> http://www.fignoggle.com/machines/r...t-problems-not-all-collets-are-made-equal.htm
> 
> ...


 I just read those articles. when I get home from work today, I'm going to measure  my collets and compare them to my R8 drill chuck. I really hope the issue is just getting better collets because thats an easy fix.


----------



## rdsii64 (Apr 23, 2015)

After reading the other artical I might  be able to get away  with sanding off a half thousandth as a temp. fix untill I can get some new 9 (read better ) collets. Now since I don't have a lathe I have to figure out how  I'm going to do this.


----------



## Billh50 (Apr 23, 2015)

I have had to remill a few keyway slots on R8 collets through the years because of not fitting. The slots seemed to be the most common problem. I have also had to replace a few thread inserts in a few because they were case hardened which caused the threads to become tight and caused the threads on the drawbar to gall and strip. I usually try the drawbar in all new collets before even tying then in a machine. If tight I check to see if it has a threaded insert that can be changed (usually only the better r8 collets have the inserts ). The next thing is how it fits into the spindle. Sometimes I will use some bluing to see where it is binding before I go further.


----------



## darkzero (Apr 23, 2015)

rdsii64 said:


> After reading the other artical I might  be able to get away  with sanding off a half thousandth as a temp. fix untill I can get some new 9 (read better ) collets. Now since I don't have a lathe I have to figure out how  I'm going to do this.


You could insert a 7/16 collet in the mill, then mount a 7/16"-20 rod in the collet. Screw a nut onto the threaded rod, then screw on the collet you want to work on using the nut to lock it in place. You could also use a drill chuck to hold the threaded rod but if you have a keyless chuck be sure to pay attention which direction you turn on the spindle so it doesn't unscrew.


----------



## chips&more (Apr 23, 2015)

darkzero said:


> Or better yet, take that stupid thing out!


I have read in the past on HM that there is no such thing as a stupid question. Is there such a thing as a stupid keyway pin?


----------



## darkzero (Apr 23, 2015)

Yup, on my mill that keyway was the stupid part. On my lathe the stupid part was the chuck guard. Both annoyed the hell out of me & had to get thrown away. I won't recommend it as I don't want to get arrested by the safety police but I'm no longer hating life without them.


----------



## rdsii64 (Apr 23, 2015)

darkzero said:


> You could insert a 7/16 collet in the mill, then mount a 7/16"-20 rod in the collet. Screw a nut onto the threaded rod, then screw on the collet you want to work on using the nut to lock it in place. You could also use a drill chuck to hold the threaded rod but if you have a keyless chuck be sure to pay attention which direction you turn on the spindle so it doesn't unscrew.


 This is promising. Since I'm going to order another draw bar anyway, I can cut off the top of my current draw bar and then put it in my drill chuck. Spin on my 7/16 collet and sand it untill it fits properly. Then
install the newly modified 7/16 collet, fit the modified draw bar (now just a threaded rod) and sand the rest of my current collet set until they fit properly. If  I'm careful and only go half thousandths or so at a time, this should work.


----------



## planeflyer21 (Apr 23, 2015)

Used a similar solution on my Smithy Granite.  Got it secondhand with one drawbar.  The accessories that came with it had different threads.

Went up to the hardware store and got a couple of feet of all-thread, a big washer, and two hex nuts to serve as a drawbar.  Worked great!


----------



## rdsii64 (Apr 24, 2015)

Well, its confirmed. My R8 collets measure .934 at the point where they bind. My R8 drill chuck measures .901 at the same spot on the shank. So that is a difference of 33 thousandths. Sanding 33 thousandths off is a lot of sanding.  I'm going to go in search of better quality collets. But since these are basically useless to me, I'm going to try to sand them anyway just to learn something and to let the inner kid out and "play with my toys". If I make them worse, no harm no foul. While I'm here what are some good brands to look at.


----------



## janvanruth (Apr 24, 2015)

why not take a file to it instead of sanding


----------



## EmilioG (Apr 24, 2015)

All of my r8 collets are Hardinge, Japan and Germany. No problems. The latest one is an import but
well made Pro series r8 jt3. Great article on collets.  I felt that collets were not all made the same which is
why I looked for the best ones I could afford.  The keyway spec is:  .156 wide x .094 deep.


----------



## darkzero (Apr 24, 2015)

rdsii64 said:


> what are some good brands to look at.


If I was looking to buy new today for quality R8 collets, I'd probably buy Lyndex or Royal. Harding collets are nice but they're pretty expensive.


----------



## RJSakowski (Apr 24, 2015)

rdsii64 said:


> Well, its confirmed. My R8 collets measure .934 at the point where they bind. My R8 drill chuck measures .901 at the same spot on the shank. So that is a difference of 33 thousandths. Sanding 33 thousandths off is a lot of sanding.  I'm going to go in search of better quality collets. But since these are basically useless to me, I'm going to try to sand them anyway just to learn something and to let the inner kid out and "play with my toys". If I make them worse, no harm no foul. While I'm here what are some good brands to look at.


Before you sand/grind/mill, the specification for the cylindrical section at the top of the collet is .9495/.949".  The central section of the collet is given as .94" or 15/16". and is not precision ground.  Since the upper portion of the collet has to move tpast this position n the socket when you seat the collet, anything less than .949 is good.  

More than likely, if you are experiencing binding it is either the keyway or you have galling in the upper portion of the spindle socket.  I would check carefully with a known good R8 tool before I started to modify any others.  

When I bought an R8 collet set, I had several that bound because of a narrow keyway.  A bluing test will confirm that interference.  I didn't have a Dremel at the time so I eliminated the interference with laborious hand honing.  A Dremel will make short work of the problem

As I understand the situation, the R8 specification was an internal Bridgeport spec. and all other manufacturers reverse engineered the Bridgeport collets or clones of same to create their own spec.  As a result, it is entirely possible that some latter day manufacturer has created a specification that has significant rounding errors.  The same is true for the spindle socket.  It is entirely possible that your spindle has a slightly larger key than typical, causing the binding.


----------



## chips&more (Apr 24, 2015)

rdsii64 said:


> Well, its confirmed. My R8 collets measure .934 at the point where they bind. My R8 drill chuck measures .901 at the same spot on the shank. So that is a difference of 33 thousandths. Sanding 33 thousandths off is a lot of sanding.  I'm going to go in search of better quality collets. But since these are basically useless to me, I'm going to try to sand them anyway just to learn something and to let the inner kid out and "play with my toys". If I make them worse, no harm no foul. While I'm here what are some good brands to look at.



Something is wrong, maybe it’s me, but I’m getting a big question mark? What does the .934 dimension reference to on the R8 collet? A pic please or drawing, or something of the problem…Thanks, Dave.


----------



## Billh50 (Apr 24, 2015)

Here's a picture:
I still say check the keyway first.


----------



## rdsii64 (Apr 24, 2015)

RJSakowski said:


> Before you sand/grind/mill, the specification for the cylindrical section at the top of the collet is .9495/.949".  The central section of the collet is given as .94" or 15/16". and is not precision ground.  Since the upper portion of the collet has to move tpast this position n the socket when you seat the collet, anything less than .949 is good.
> 
> More than likely, if you are experiencing binding it is either the keyway or you have galling in the upper portion of the spindle socket.  I would check carefully with a known good R8 tool before I started to modify any others.
> 
> ...


 
This is something I failed to look at. After re-reading you post, this sounds more plausible since the top of the collet measures .949 (My caliper actualy measured it at .950) It looks like I will be chucking a drimmel attachment in my drill chuck and  SLIGHTLY open up the keyway and see if it works.
first I'll measure the keyway in my R8 drill chuck since it goes in and comes out properly, and If I find a difference, I'll match then with my dremmel atatchment.


----------



## FanMan (Apr 24, 2015)

I had the opposite problem; all the collets that came with my mill fit fine but the R8 drill chuck spindle I bought on ebay didn't.  It was slightly oversize right along the keyway; a friend chucked it up on the lathe and lightly polished it until it was the right size.


----------



## RJSakowski (Apr 24, 2015)

rdsii64 said:


> This is something I failed to look at. After re-reading you post, this sounds more plausible since the top of the collet measures .949 (My caliper actualy measured it at .950) It looks like I will be chucking a drimmel attachment in my drill chuck and  SLIGHTLY open up the keyway and see if it works.
> first I'll measure the keyway in my R8 drill chuck since it goes in and comes out properly, and If I find a difference, I'll match then with my dremmel atatchment.


Use bluing to find exactly where the interference is.  If you don't have bluing, a blue Sharpie will work.  The keyway may be too narrow or too shallow.


----------



## Billh50 (Apr 24, 2015)

You can also use the shank end of a 5/32 (.1562) drill bit to see if the slot is wide enough. Just run it up the slot to see if it hangs up somewhere.


----------



## rdsii64 (Apr 25, 2015)

I just got home from work and measure the key way depth of my collets and compared them to the key way depth of my R8 drill chuck. The drill chuck is deeper. The Key way on my 5/16 collet is .094 and my drill chuck is .134 deep.


----------



## rdsii64 (Apr 25, 2015)

darkzero said:


> Or better yet, take that stupid thing out!


How would I do such a thing.


----------



## Billh50 (Apr 25, 2015)

Have you checked the width of the slot yet?  Was there a tight spot ? From what I saw a depth of .094 is in spec. So if it is the depth causing the problem then the pin in the spindle is sticking out more than it should and you would have problems with many different collets made.


----------



## RJSakowski (Apr 25, 2015)

Billh50 said:


> Have you checked the width of the slot yet?  Was there a tight spot ? From what I saw a depth of .094 is in spec. So if it is the depth causing the problem then the pin in the spindle is sticking out more than it should and you would have problems with many different collets made.


We had a problem with the key on a Grizzly G0755 mill at work.  The pin was a set screw which worked its way deeper causing an interference.  I machined the tip of a socket head cap screw and inserted it instead.  Now it cannot work deeper and the crew can be tightened against the spindle wall instead of floating.

To access, I lowered the quill and was able to reach the spindle through a slot in the quill.

Or once you remove the offending pin, you can just leave it out.


----------



## Billh50 (Apr 25, 2015)

I just thought it would be a good idea to check width before possibly doing something that didn't really need to be done. I always check everything first. If collet is within specs then yes I would either remove pin or fix it. I don't like removing pins because I had a drawbar gall up in a collet once and the spindle pin was removed. Had a heck of a time getting the collet and drawbar out.


----------



## RJSakowski (Apr 25, 2015)

Billh50 said:


> I don't like removing pins because I had a drawbar gall up in a collet once and the spindle pin was removed. Had a heck of a time getting the collet and drawbar out.


Good point!  That may have been the original reason for keying the spindle.


----------



## benmychree (Apr 27, 2015)

darkzero said:


> Or better yet, take that stupid thing out!


Agreed; I had a Induma Vertical mill, more or less Bridgeport style, (Italian)  where the pin was sheared off and the rack gear teeth were broken, so ordered a new quill and also the pin;  I refitted the quill, and replaced the pin, and it was only a very short time that the pin sheared off again, and was never replaced (or needed) again; that was about 25 years ago or so, and it was never missed.  One has to disassemble the spindle from the quill to accomplish replacement.


----------



## ARKnack (Apr 27, 2015)

Billh50 said:


> I have had to remill a few keyway slots on R8 collets through the years because of not fitting. The slots seemed to be the most common problem. I have also had to replace a few thread inserts in a few because they were case hardened which caused the threads to become tight and caused the threads on the drawbar to gall and strip. I usually try the drawbar in all new collets before even tying then in a machine. If tight I check to see if it has a threaded insert that can be changed (usually only the better r8 collets have the inserts ). The next thing is how it fits into the spindle. Sometimes I will use some bluing to see where it is binding before I go further.



Actually, my mill doesn't even have a key for the keyway. Somebody in the past removed it. I remember reading that removing the collet key was a common practice with machinist. I haven't had any problems with out the key.


----------



## Billh50 (Apr 27, 2015)

I only had the problem once of a draw bar galling. But it was enough to make me leave the key in. Took me a while to figure out how to get the galled up drawbar out when the collet kept spinning. I do know how to get them out easily now but just don't want to take the chance.


----------



## rdsii64 (Apr 27, 2015)

I called littlemachineshop.com today and explained my problem. It seems that Sieg ( the company who actually makes the X2 mini mill) had a bad run of mills with this very problem. A Sieg rep had to replace the spindles in LMS's current stock of mills. They issued me an RMA for a new spindle. When I told them I didn't have access to a hydrolic press, they said they would to ship me out a complete head less the motor. All I have to do is swap heads, put my motor and belt drive kit on the new head. I'm now just waiting for the rep to email or call me with who is shipping first. Hopefully they will ship me the new head first so I can use the same shipping box for the return trip.  The rep I talked to on the phone is pretty sure the problem is not with my collets. Having to dismantle my mill is kind of a bummer but at least the company is making it right.  The bright side is I will VERY WELL AQUAINTED with my mill when this is all said and done.


----------



## timbertoes (Apr 27, 2015)

Not sure I understand what the problem is 100% - however I will add:
I have had several R8 collets whose keyway was not long enough.  collet would come up short in the spindle.  Milled the collet keyway longer, and the collet fit correctly.


----------



## RJSakowski (Apr 27, 2015)

timbertoes said:


> Not sure I understand what the problem is 100% - however I will add:
> I have had several R8 collets whose keyway was not long enough.  collet would come up short in the spindle.  Milled the collet keyway longer, and the collet fit correctly.


I just checked my two machines.  On the mill/drill I hit the bottom of the key at 1.5" above the face of the spindle; on the Tormach it is 2.3 above the face of the spindle. As I said earlier, It is my understanding that the R8 collet system is an internal Bridgeport standard and different manufacturers came up with their own specs.


----------



## Doubleeboy (Apr 27, 2015)

I have a several Lyndex collets for my mill R8.  They are fine, fit the keyway, taper and threads of drawbar fine.  I bought a full set of collets from one of the China suppliers, and they fit dreadfully, returned them and bought the Enco branded set, they do not fit quite as well as the Lyndex but they are usable and accurate and way cheaper.   One good practice is to blow out your collet threads from time to time, clean the threads on the drawbar and put a drop of oil on the threads every once in a while.  I know a chap who runs a pretty large shop and every January every mill gets a new drawbar and old ones are scrapped, saves them time, money and frustration.  Based on his example, I replace my draw bar every five years and each time I have done it I have smiled realizing that using my mill is now easier than it was a week earlier.   Dorian drawbars only for me, no imports.

michael


----------



## rdsii64 (Apr 28, 2015)

Today after I got back home from taking my wife to her appointment, I took the motor, belt, and drive pulley, off my head. I boxed it up and shipped it back to Littlemachineshop.com.  They are going to replace my spindle, and ship the head back to me. Shipping both ways is on their dime as well. After it arrives I'll call them and try to get a general time frame for how long this should take. I hope I get lucky and they just ship me a new head. I forgot to take the driven pulley off the spindle so I ordered a second driven pulley just in case they ship me a new head and forget to take the driven pulley off the old one.


----------



## 1tcoffman (Apr 29, 2015)

rdsii64 said:


> I have a very weird problem with my mill. When ever I have to remove or reinstall my R8 shank drill chuck, it goes off with out a hitch.  All I have to do is lossen the draw bar a half turn,  give a light tap with a hammer or rubber mallet, then back out the draw bar and easy peasy its done. I actually have to hold my hand under it to catch it when it falls out. Its that easy.
> 
> My R8 collets are another affair. Installing a removing an R8 is such a fight I have actually galled the threads on my draw bar and had to replace it.  Inf fact I actually have to tap the collet up into the spindal so the draw bar can thread into it.  I know this can't be right I just don't why, nore how to fix it.
> 
> ...


 I had the same problem when I got my HF mill last winter. It happened with the very first collet I had at the time. After going through all the channels on the internet, I finally just looked at the collet and noted where it it was shiny and scarred. Used some fine wet or dry sandpaper until it worked. I've never had the problem with the other 2 collets I bought, so it must be a manufacturing problem.


----------



## rdsii64 (Apr 30, 2015)

Got a call from littlemachineshop.com today before I left work. They got my mill head today and the rep I spoke to said the spindle would be replace today and should go out in todays mail on its way back to me. Since I have a belt drive conversion kit, they removed the internal plastic gears for free. It was a bummer to have to dismantle my mill but the company made it right and their customer service was top notch. When I get my milll head back and my modulus arms jig is delivered my projects can resume.


----------



## higgite (Apr 30, 2015)

rdsii64,

I've been eyeballing a LMS mini mill, just haven't pulled the trigger, yet. So, this thread has been very informative for me. I already knew from experience that LMS customer service is top notch, but have gleaned some valuable knowledge about collets/spindles/keys/keyways without the inconvenience that you have experienced. Thanks for posting and thanks to those who reponded.

Tom


----------



## rdsii64 (May 1, 2015)

higgite said:


> rdsii64,
> 
> I've been eyeballing a LMS mini mill, just haven't pulled the trigger, yet. So, this thread has been very informative for me. I already knew from experience that LMS customer service is top notch, but have gleaned some valuable knowledge about collets/spindles/keys/keyways without the inconvenience that you have experienced. Thanks for posting and thanks to those who reponded.
> 
> Tom


 When I got up today, I went to put gas in my wifes car and when I got back home, my mill head was  delivered. When I get home I'll get it back on my mill and  will report back.


----------



## rdsii64 (May 2, 2015)

When I got home form work today. I unboxed my mill head, put it back on my mill.  After I put the motor and drive belt back on I reach for my 5/16 R8 collet.
Low and behold, my collets now go in and out as easily as they are supposed to. A quarter turn of the draw bar, a light tap, then loosen the draw bar the rest of the way by hand and the collet slips right out.  From the time I dropped off at the postal annex to the time it was back on my door step was less than three days.
Once again all is right with the world.


----------

