I was recently using an up cut spiral bit to cut a groove in some red oak using my router table. During the cut the bit started moving up out of the chuck. I sprayed the bit shank with some contact cement and continued on with the job. That seemed to work ok, but I was wondering what others do to prevent this from happening.
Thanks, LD
Replies
I for one would replace that chuck if it happen again!
Could just need a GOOD cleaning though...
LD,
That happened to me too...Whiteside up cut spiral bit. I called DeWalt and they sent me a new chuck(that is not the actual name...but, getting old)...no charge, however you can buy replacements for about $20. Anyhow, I was so unsure about the cause..I never use it in the router table anymore...I've relegated it to the hand held router and there it has worked fine (my handheld is an old BD from the early 70's)
On a router it's called a "collet", not a chuck.
Are the surfaces of the collet and the bit clean? If they are not perfectly smooth, the bit will slip. Check for a build-up of brown or black depostis; i.e., "collet burn". See http://www.woodhaven.com/FAQShow.aspx?ID=1748
I'd discard the collet and get a new one, and make sure the bit shaft is clean.
I recall having recently read about the propensity of these bits to move under load; I believe http://www.patwarner.com is where I saw the info.
-Jazzdogg-
"Don't ask yourself what the world needs. Ask yourself what makes you come alive, and go do that, because what the world needs is people who have come alive." Gil Bailie
I have both PC and Bosch routers and have never had a problem with bit slippage in the collet. However, the bit shank and collet need to be clean, and obviously you need to make certain you have adequately tightened the bit down in the first place. Some of the collets for these machines are more than 20 years old and still working fine -- even though they have been used hard.
Woodhaven (see Barry0's link) sells a set of round brass brushes which I highly recommend for cleaning the inside surface of a collet. If you ask, they will also send you a free pamphlet on collet/bit maintenance.
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Not sure if I am correct.. But a old metal worker here..If you tighten a collet to tight it will distort and not hold correctly.. Old Tank mechanic here so I KNOW TIGHT!Just tighten the nuts without 'undo?' stress.. Whatever that is.. As in where the wrench stops and a 'bit' more...Before I use my routers I blow out the collets with air..I get really sick when I see the pictures of so call experts cleaning a collet with sand paper!
Hey Will: Maybe you can advise me on this one: on my Bosch 1617 the collet when loosening it gets to a point where it is loose but the bit is not. About a half a turn latter(still going in the loose direction) it gets tight again and past that it and the bit are loose. It happens with all the bits, every thing looks clean and shiny, none of the bits slip. ?
Thanks, KDMKenneth Duke Masters
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That is a feature of the new colletts - that's how they release. Can't remember the technical name, but beats the heck out of a stuck bit! My PC works the same way.
My PC's do the same thing.. Both are relatively new.I never paid that much attention to the details of how it works.. Just thought it was strange and forgot about it..None of my metal working collets or mandrels work that way. I guess I need to look into it..I have never had a bit slip on me.. Even on my bunch of old Ryobi's and some of the bits I use are large.. I do not crank down on the nut. Just moderate tightening.However I NEVER take deep cuts.
With the PC collets (the newer ones, anyway), when you loosen the nut, the bit will not loosen, until you loosen the nut enough to hit the bottom of the snap ring and "pop" the collet up from the router shaft.
That's how you can tell something's not right - if the bit gets loose as soon as the collet nut gets loose. That indicates that the surfaces are not mating very well. They should stay together by friction alone (like the chuck on a drill press stays on the taper by friction alone), until released by another mechanism.
I have also experienced the drifting bit. I was plunge cutting mortises with an up cut sprial. It was making a lot of racket and chatter - my theory was that I was trying to take too big a bite so I backed off on the depth (like to 4 passes instead of 2) and no more problems.
LD,
I was just doing some mortices in white oak...2" long, 1/4" bite at a time. My Whitesides Up-sprial just broke in three pieces..two pieces were in the collet. I had not used if very much, it had never been dropped and I was not forcing.
solid carbide bits are brittle. They break pretty frequently
BarryO,
Thanks,I did not realize they might behave that way. Because I had the same problem as LD did with slippage and this bit, I thought maybe the slippage was foreboding of things to come...like a weak spot...or out of spec...etc. Anyhow, maybe it's time for that leather apron...
Thanks to all that replied. I learned that the collet design on my router is one of the poorest. Also that it's called a collet not a chuck. That other people have experience similar problems and that the problem was probably due to the bite I was taking. I was trying to cut 1/4 by a 1/2" mortise. That was probably too much. In the future I'll do that job in 2 stages. My collet and bit were clean, so I know that wasn't the issue. My answer at the time was to use a little contact cement. That worked, but it might not be an answer for the purist.Dave
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