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R-8 collets

lfgt

Aluminum
Joined
Oct 23, 2007
Location
Missouri
Yesterday was my first class of the semester. I was talking to one of the instructors. Over the summer they had gone through the collets dumping worn or broken collets. They combined old sets and set up a few mills with new sets from Enco. The new sets are sticking badly and are hard to get out of the machine. Is this a common problem?, or did we just get a "GOOD BATCH"?

I was getting ready to order a set and am on a budget, But if there is a problem with consistancy Ill purchase something better to work with.

Jim
 
I have had the same problem with discount R8 collets in the past. If you chuck one end in the lathe in some aluminum jaws that are bored correctly for the collets, you can polish the diameter in question with sand paper to take a few tenths off. Also, check the inside of the spindle of the mill to make sure that it is clean.
 
Yep, the cheapo collets are sometimes a bit oversize. I just used some wet or dry paper and the lathe to take up to .0005 off. Around half of them were like that in the set I bought. I guess you get what you pay for.
 
How do you clean out the spindle taper?

What method do people use to clean out the spindle taper of the mill?

I suspect that a small chip has become lodged deep within the taper of one machine that I use.
 
Not OT but slightly to the side

How come I can't find R-8 collet dimensions in Machinery's Handbook. Too stupid is one answer and perhaps, proprietary is one more? Any thoughts from the Council of Elders? Some call me Carlos.
 
I've had to polish a few before, also cleaned up the keyway a little with a honing stone.
 
What method do people use to clean out the spindle taper of the mill?

I suspect that a small chip has become lodged deep within the taper of one machine that I use.
When it is stopped, you can take a small mirror and a flashlight and examine it for damage or chips.
The safer way to clean one out is take a piece of wooden dowel, cut a slot in it so that it will accept a piece of scotch brite. Have you removed that annoying key that is in there yet? If not, it is up to you, but that is always the first thing that I do when I buy a mill. If so, you can run the spindle on a slow RPM, say 150 or so, use some light oil on the scotch brite pad, and polish the spindle taper manually. (He ducks as large projectiles are hurled at him by other machinists who hate this idea.)
 
Thanks for the responces. I would rather not polish/alter a new set of collets. I would rather pay a little more more for a better product. I have an order ready for Enco and would like to take advantage of free shipping. Is their Lyndex collet set a better choice, or do I go elswhere? Many makers out there where is the best value?
 
I spoke to their tech support yesterday ref 5C collets. Not too helpful but seemed to think that Enco collets had up to .005 tir. Lyndex .0005. YMMV
Rich
 
Thanks for the responces. I would rather not polish/alter a new set of collets. I would rather pay a little more more for a better product. I have an order ready for Enco and would like to take advantage of free shipping. Is their Lyndex collet set a better choice, or do I go elswhere? Many makers out there where is the best value?

Jim,

I am not sure about Lyndex as opposed to the Enco brand. I think there are some collets sold under the "Nuline" brand that are supposed to have better specs than the cheapest of collets.

I think the consensus is that Hardinge are the best collets. Of course, they cost more. I also think that the Royal brand are really good.

I am not sure that I would be able to tell the difference in finish between parts made with one brand of collet or another, but I do notice that the premium brand collets fit better when installing.

One option is to get the premium brand collet in a few of the most commonly used sizes, like 3/4" and 1/2", and then also get an entire set of cheap collets. You can pick up a set of R8 collets spanning all sizes from 1/8" to 7/8" by 16ths on eBay for really cheap.

Jon

p.s. I would not believe the sales rep about .005" TIR for any brand of collet. That sounds ridiculously high. (But I have been wrong before, at least once or twice in this lifetime...) :-)
 
Lyndex

I have used Lyndex brand collets in the past, and I think that they are definitely better than the $4.25 each discount cheapo ones. Not as good as Royal or Hardinge as stated earlier, but definitely acceptable quality. By the way, I never had a NEW collet discount or otherwise run out any more than .001 TIR. Maybe I have been lucky so far, I don't know.
 
"Is their Lyndex collet set a better choice"

Maybe I got a bad batch, and this was several years ago, but I bought a Lyndex 1/16" set and several of them had threads out of spec, wouldn't thread smoothly on my Royal closer. Also several had over 0.0015" of runout.

I sent them back and bought Hardinge in my common sizes (1", 1/2", etc.) and a full 1/64" of the cheapos from Enco for off-sizes. The enco ones, at least at the time, weren't too bad, a few had dinged threads and they replaced them with no hassle. I find the import ones are typically a little tight compared to a "real" 5C collet (only Hardinge is left, Royal doesn't make them anymore, they sell imports now too) but other than that the cheapies have been ok for me, I abuse them since they don't cost much but so far they have stood up to it.

Paul T.
 
Collets

Check the 'anti-rotation pin in the spindle. I have had past problems with my old mill and found the slot for the pin to be the problem. Occasionally the same problem happens with the 5-C collets for my lathe.

JRW
 








 
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