View Full Version : Lube on collet tapers?

02-23-2006, 10:12 PM
Just wondering if it's better to leave the closing taper on a collet dry or give it wipe of oil? Lube the threads?

02-23-2006, 10:20 PM
My guess would be a wipe of oil on the tapper and threads would make it close easier, as long as the oil is kept out of the hole. Gary P. Hansen

02-24-2006, 05:50 PM
I'm hoping someone with more experience can confirm this, but I've been told never to oil a taper.

A (very) little grease on the threads seems like it might be OK. I'd put it on the drawbar rather than the collet, though, so you didn't risk smearing the grease on the taper while inserting the collet into the tool.


02-24-2006, 06:15 PM
you want it clean and dry , Oil would be a dirt magnet.

02-24-2006, 09:51 PM
Shallow taper collets work because of metal to metal friction, lube defeats this and increases the risk of collet rotating inside the spindle, generally recognized as bad. Of course with milling spindles, between the key and the drawbar, this is an likely scenario, but that is what I understand of the theory.
Between that and the problem of dust and chips sticking into the lube and scratching things up, it would seem lubing collets is a very bad idea.

02-24-2006, 09:52 PM

[This message has been edited by sch (edited 02-25-2006).]

02-24-2006, 10:19 PM
The original question was for a spring collet, at least I assume so from the "closing taper" part of the description, and for that a bit of oil doesn't hurt, totally dry (degreased dry) would not be a real good idea. A dry taper in a locking taper (Morse, B&S, etc.) is required for the taper to hold.

If you go from a dry to a wet taper be sure to watch the clamping force - you'll be able to pull the collet a lot further than you were before.

02-25-2006, 05:04 AM
Definitely use grease or oil on the taper. Clamping force is much greater with lubrication. Also wear on the collet seat is lessened.

I run a couple bar fed automatic lathes with 5C collets. When running parts dry, no coolant, after a short while the collet will stick closed. On these jobs we stop the machine every hour or so and apply a bit of anti-seize grease to the taper.

02-25-2006, 12:50 PM
I'm glad you're getting more replies on this, I figured I didn't have all the answers! http://bbs.homeshopmachinist.net//smile.gif

I had been thinking Morse or Jacobs type tapers, and there I'm sure from personal experience you want 'em dry. http://bbs.homeshopmachinist.net//redface.gif

If you oil a collet, how do you keep it out of the bore, or do you care?

If lubing a 5C is good, what about an R8? Is there some sort of general rule to apply to figure out whether to lube or not (besides 'it stuck when I didn't' or 'it spun when I did')? How to not screw up a spindle isn't something I want to learn by process of elimination! http://bbs.homeshopmachinist.net//smile.gif


02-25-2006, 05:16 PM
Thanks for all the responses. I kinda had a feeling that it would be good to lub the closing area of the taper (outside). Or just give the inside of the closer a swipe.

Walt - As Rkepler mentioned, I wouldn't lube any taper that relies on friction to hold. (Jacobs, Morse, etc.) My collets have a pin that keep them from rotating. I wouldn't lube the tool/stock or the inside (bore) of the collet.

I've done it for storage but always wash them in thinner before use.

02-25-2006, 08:35 PM

Don't count on the pin for driving force. It's intended just to keep the collet from spinning as the drawbar is tightened. In fact, I've worked on mills in shops where the key was gone. It still runs fine, you just have to hold the collet every once in a while as you tighten up.