# R-8 Self centering chuck for a mill?



## negatronix (Oct 14, 2014)

Hi! I am looking for some help with a R-8 Self centering chuck.

I have seen mini-chucks available at Shars/Grizzly and am curious if I can expect one to work for me and my basic needs. Is it possible to really clamp down tight with a mini-chuck.

I am looking to take 1-1/2" solid round  4130 and make some bungs for tierod ends on a suspension project. The bungs will be 2" long, have a 5/8 -18 threaded hole through the entire length of the part, and be stepped to fit into a piece of tubing.

Are there any R-8 adapters that would allow me to buy a 4" or 6" self centering chuck and bolt it up for use on my mill.

Sorry for the total noob question. I am just starting out, and have much to learn.

Thanks,
-Kory


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## Rbeckett (Oct 14, 2014)

I would recommend a set of ER-32 collets and they will definitely hold it tight and centered.  That Is the best way to do it and will give you consistently repeatable result if you are making more than one.  I got my ER-32 set for my MT2 machine pretty cheap and it works great!!!

Bob


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## Tony Wells (Oct 14, 2014)

Don't worry about the questions, they are the cure for noobism  

So, in essence, you want to use your mill for an vertical lathe, with cutting tools held on the table or in vise.....right? I can't say I'd be too crazy about doing that. Chucks can be had with a variety of mounting systems, but I don't think an R8 is made. Of course, the beauty of machining is that many times we can simply make what we need or want. To adapt a plain back lathe chuck to a mill you would need to do some lathe work. I am guessing you don't have a lathe yet, hence this situation. 

If you did manage to cobble something together, bear in mind that it would be very light duty and limber. Mill spindles are built differently than lathe spindles.


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## darkzero (Oct 14, 2014)

I've also never seen a commercially made R8 adapter for a lathe chuck (until now ↓) but I have seen chucks used in mill spindles. But usually not that big, probably 3-4" might be ok. A 6" chuck seems way to big & heavy for an R8 spindle to me.


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## kd4gij (Oct 14, 2014)

Except er32 wont hold 1 1/2" stock Er40 only goes to 1 1/8".

 Here is what you are looking for.
http://www.shars.com/products/view/973/3quot_3_Jaw_Self_Centering_Precision_Chuck_amp_R8_Arbor


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## kd4gij (Oct 14, 2014)

Another option if you have a boring head for your mill you can install the boring bar facing inwards and turn the part that way.


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## darkzero (Oct 14, 2014)

kd4gij said:


> Er40 only goes 10 1 1/8".



I'm sure you meant 1-1/8" but I maybe you were thinking of 5C? Normal max capacity for ER40 is 1.00" for standard & 26mm for metric collets. However Maritool does make "special range" collets larger than the normal range that go up to 1-3/16" for standard & 28mm for metric. They are the only ones I have seen that make "oversized" ER40 collets.


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## John Hasler (Oct 14, 2014)

I've lathed on my mill.  The finish could have been better, but it worked.  I suggest that rather than mounting a chuck you make a mandrel and mount your part by the center hole.  Drill and tap the part, screw it onto the (threaded) mandrel, and lock it with a nut.


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## Tony Wells (Oct 14, 2014)

That's a new one on me too. I'd still be a little leery of the duty rating, especially on a benchtop machine.


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## kd4gij (Oct 14, 2014)

I am not  shure where we ordered them from and there is no room for a size stamp but we had 10 er40 collets that a will hold a 1 1/8 gauge pin or a 28mm pin. Where ever thay where ordered we got them in 3 days. Now thay could of come from the machine manufacture. I worked on rotery transfer machines.


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## chuckorlando (Oct 14, 2014)

I have also turned on my bridgy. Blue chip and nice finish. But it was in a collet. My instructor started his cnc shop with a bridgy and a 3 jaw (before he had cnc). I dont know how many you need but I believe I paid 5 bucks a pop for my 5/8 heim bungs for 1.25/.095 dom a-arms


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## Andre (Oct 14, 2014)

I have used my mill as a backwards vertical lathe. It works great, no issues with it. And setting tool height is a snap!
Just take it easy, it should work out fine.


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## chuckorlando (Oct 14, 2014)

http://www.ebay.com/itm/5-8-18-RH-W...pt=Race_Car_Parts&hash=item5d4717c515&vxp=mtr

http://www.ebay.com/itm/Weld-In-Thr...Parts_Accessories&hash=item27ebfb9d75&vxp=mtr

http://www.ebay.com/itm/Weld-In-Thr...Parts_Accessories&hash=item27ebfb9d77&vxp=mtr

There are tons of them


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## kd4gij (Oct 14, 2014)

Looks like he has an rf 45 calone. It would spin that 3 1/2" chuck allright. But I think the boreing head would be the better rout to take.


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## chuckorlando (Oct 14, 2014)

So your saying turn the cutter around so it turn an od instead of a id?





kd4gij said:


> Looks like he has an rf 45 calone. It would spin that 3 1/2" chuck allright. But I think the boreing head would be the better rout to take.


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## Andre (Oct 14, 2014)

chuckorlando said:


> So your saying turn the cutter around so it turn an od instead of a id?



Yep, and run the mill in reverse. Or use a LH boring bar and run it forward if you prefer, but LH boring bars are not common shop items.


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## chips&more (Oct 14, 2014)

Andre said:


> Yep, and run the mill in reverse. Or use a LH boring bar and run it forward if you prefer, but LH boring bars are not common shop items.



I looked for a set of LH boring bars a while back. And yes, they are not common, in fact, I could not find anybody selling them? I hand to make my own! If anybody knows of a source, I think the HM group would like hear.


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## chuckorlando (Oct 14, 2014)

http://www.ebay.com/sch/i.html?_odk...lh+boring+bar&_nkw=lh+boring+bar&_sacat=11804

Plenty on ebay


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## chips&more (Oct 14, 2014)

I have had one of those 3 jaw chucks with a R8 arbor for about 10 years now. It’s been neglected for so long I can’t recall where it is. I also have one of those spinning chucks for the lathe tail stock. Same story, don’t know where I put it. Conclusion to some of you tool aholics like myself…don’t ask me for advice or you’ll be storing crap you can’t find anymore!


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## darkzero (Oct 14, 2014)

> chips&more said:
> 
> 
> > I looked for a set of LH boring bars a while back. And yes, they are not common, in fact, I could not find anybody selling them? I hand to make my own! If anybody knows of a source, I think the HM group would like hear.
> ...



I had just posted various sources on LH boring bars too but realized that I don't think that's what he meant & deleted it. I believe he meant LH boring bar sets for use in boring heads. Boring head boring bars are shorter than those commonly used on lathes. Boring bar set for boring heads are all one shank size but in different lengths. Of course you could always cut one down to length if needed.

But yeah, I've never seen LH boring bar sets for boring heads commonly available.  Mesa tools make short indexable boring bars for use in boring heads but not in sets, just one length per boring head size. 2" boring head - 1/2" x 3" boring bar. 3" boring head - 3/4" x 4.5" boring bar.


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## negatronix (Oct 23, 2014)

Sorry to neglect this thread everyone.. I've been looking at vises, and a few other things.

I'm liking the boring head idea and making one happens to be one of the projects in my getting started book. I am envisioning mounting a chuck on my rotary table to hold the part, boring the center hole, taping it, then turning the OD step to the desired size using a boring head as suggested... Does that sound like a good approach?

I would buy the bungs, however I have quite a bit of solid bar on hand, and need the experience!!

Thanks for the help!
-Kory


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## chuckorlando (Oct 23, 2014)

hahahah No worries. It was those very bungs that got me into machines. 5 bucks is pretty cheap till you need a bunch and it adds up. And God forbid your first concept dont work and you have to do it all over. Plus your not limited to what others make. 

Whats this book you got? Getting started?


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## negatronix (Oct 23, 2014)

The book is "Milling for the Home Machinist". Its a small book with a few nice projects that build on one another a bit.

My wife bought me the book for Christmas last year after helping me decide  that a change needed to be made in my life. I became quite ill in 2008, and had to give up a wonderful career. I spent the better part of 4-5 years getting well.

I am far healthier, happier, and wiser now after my illness, and am headed in a new direction that will hopefully bring me happiness and far less stress. 

I really appreciate your help and direction Chuck. As much as I wanted the vise I mentioned in the other thread your advice and the others that chimed in showed me a better route, just like in this thread. I tend to throw a lot out there in a thread hoping to get a bunch of feedback that I can boil down to a good resolve.. this forum delivers that every time!

Thanks everyone!

Once my vise, and rotary table get here, I'll chime back in on this thread to get some help with figuring out what I'll need to make the bungs.

-Kory


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## Pat of TN (Oct 29, 2014)

If you're getting a rotary table, just use it with an end mill. Center the end mill in the Y or X axis on the part, move it to the piece, turn the rotab. A lighter mill may see some chatter, but, lighter cuts may relieve that.

The reason I say this is, with a CNC mill, you can mill round shapes (or oval, or elliptical, etc., etc.). You can mill darn near any part that you would normally turn. Well, a manual mill with a rotary table gives you a similar capability, excluding elliptical parts barring some extreme circumstance/equipment.


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## negatronix (Oct 30, 2014)

Pat- I've abandoned the R-8 chuck idea, as I have purchased a rotary table. 
I will certainly try what you are describing. It seems like it would work well for both the horizontal or vertical positioning of the RT.

I need to make a spacer first to lift the RT a bit... when I disengage the worm gear the handle doesn't clear the mills table. Once I finish that, I will give it a try, and chime back in! I'll post a few photos as well.

Thanks!


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## Pat of TN (Nov 2, 2014)

Not a problem, friend. My only recommendation is, make sure the parts are held well and make sure that your mill is trammed well to the table, and the rotab parallel with the table. Right-hand-helix tools produce a lifting force on work, so if the piece isn't clamped or chucked well, it can be pulled up and out. But it should give no issue, and of course, making sure the workpiece is secured properly is really step 1 for any setup.

Glad I could help you, though!


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## negatronix (Nov 3, 2014)

Pat- You say right-hand-helix tools produce a lifting force on the workpiece... maybe a very dumb question, but with a right-hand-helix, would running the machine in reverse have the opposite effect? This would be down-milling, right?

I plan to be extremely cautious with clamping. I need all my fingers and both eyes... rather valuable to me!


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## xalky (Nov 3, 2014)

negatronix said:


> Pat- You say right-hand-helix tools produce a lifting force on the workpiece... maybe a very dumb question, but with a right-hand-helix, would running the machine in reverse have the opposite effect? This would be down-milling, right?
> 
> I plan to be extremely cautious with clamping. I need all my fingers and both eyes... rather valuable to me!


Then the cutter won't be cutting at all. It'll just run the wrong way and get dull. Heck, if you do it long enough, you'll friction weld it to the work piece.


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## negatronix (Nov 3, 2014)

Xalky- I see what you are saying... I guess I don't understand how the lift would be prevented.. That's why I put the dumb question  comment. 

Will you explain what I am missing here..? 

Thanks!


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## JimDawson (Nov 4, 2014)

negatronix said:


> Xalky- I see what you are saying... I guess I don't understand how the lift would be prevented.. That's why I put the dumb question  comment.
> 
> Will you explain what I am missing here..?
> 
> Thanks!



Right hand cut, Left hand spiral, down cut end mills exist.  The helix is backwards from a normal end mill, strange looking things.  They put down pressure on the work when cutting.  I have only used them in CNC routers when cutting plastic.  They do exist for metal cutting, but are not common.


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## negatronix (Nov 4, 2014)

JimDawson said:


> Right hand cut, Left hand spiral, down cut end mills exist.  The helix is backwards from a normal end mill, strange looking things.  They put down pressure on the work when cutting.  I have only used them in CNC routers when cutting plastic.  They do exist for metal cutting, but are not common.


Ahhh... I understand, I think. I will google one and take a look.

 Thanks!


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## negatronix (Nov 4, 2014)

Hmmm, just saw your pic in my reply. Thanks again.


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## Pat of TN (Nov 10, 2014)

Yeah, you can't prevent the up-lifting force of a right-hand twist. That's just how it works, unfortunately. I have seen left-hand helix, right-hand-cut end mills as well. Very very curious items.

But, not worth buying for hobby machining and such, if they can be found. Just take things easy.

As a note, running an end mill or reamer or really any cutting tool backwards will basically cause instant destruction. Every carbide end mill, especially, that I have ever seen run backwards simply explodes on touching the piece.

Of course, you could also buy left-hand end mills if your mill will spin in reverse! Just don't get confused.


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