Bit slipping out of collet

[cr2]

Twice recently I've had a 1/4" upcut bit slip down in the collet of my porter cable router while making a profile pass. The material is hardwood and I'm cutting .030" off in one pass at a depth of .735". Speed is 50 ipm. I decided to throw away the collet and have ordered some of the ER collets from PreciseBits.com. Now to my question: Will the new ER collets hold the upcut bit tight enough to keep this from happening, or should I also switch to downcut bits. I prefer upcut because I use carbide end mills that are reasonably priced compared to the downcut router bits.

Thanks,

Charlie

[bleeth]

Your problem should be over with the new collet.

[michael_schwartz]

You made the right decision to throw away the collet.

If you still have a problem the bit is too small.

[englert]

There are two types of collets. If you look closely at them, some are split or have multiple splits from one end only, while others are split from both sides alternately. When the collor nut is tightened, the one split from both ends will compress evenly along the length of the bit. Whereas, the one that is split only from one end has a tendency to crimp the bit at one end or simply, it does not clamp evenly along the length of the bit.

Also, I agree with the other comments. Once you slip a bit in a collet, get rid of the collet plus your bit is probably suspect also.

Dennis

[phil_o]

Have you tried doing a thorough cleaning of the collet? I had the same problem, bit slippage. I used a credit card to get into all of the openings and clean out the debris. It worked quite well. You may need a magnifying glass to do a good inspection.

Phil

[cr2]

Thanks for all the comments and advice. The new collets are arriving today and I will definitely take more care in keeping them, and the spindle bore, clean.

[michael_schwartz]

When in doubt throw them out.

I have seen some scarry situations resulting from the use of a bad collet.

Keeping spares around is advisable as you won't be tempted to one that is questionable.

[gundog]

Here is a little collet 101 Never bottom out the bit in the collet always leave a little room. It is possible to not get the bit tighted properly because as the collet closes it draws the bit up if it can't move up it will not tighten properly. I have watched several people do this in the past.

Mike