Make sure to keep your router collets spotless. Earlier tonight I was routing out some dovetails, and I was using a carbide endmill to rough out most of the wood. Everything was going smooth until I got to the quartersawn oak drawerfronts. At first things were going fine, then it started to feel like my cutter was a little dull. The next thing I new there was smoke, so I stopped and looked at the cutter. It was still razor sharp, but then it hit me. The bit had slipped and as a result the shank was also rubbing and cutting.
This really sucked, but fortunately I should be able to save the drawer fronts. I’m pretty sure the cause was that there is some grime inside the collet, although I have no idea how it managed to get there. So just a warning to others, keep your collets clean. I’m thankful that this didn’t happen to a more expensive piece of wood, or in a situation where I would be forced to scrap everything.
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"so I stopped and looked at the cutter. It was still razor sharp, but then it hit me. " Your phrasing 'bout gave me a heart attack! Glad everything worked out Andrew. All collets get gunk in them over a period of time. Much better to learn the lesson by losing a little lumber than by having the big come out of the collet and sever a body part.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Andrew, Solid carbide is very slick and should be cleaned with acetone or lacquer thinner if the least bit oily.
Check your collet for wear. If you are using a collet reducer, orient the 'splits'or 'gaps'lines so they line up with each other. Also Never push the bit entirely into the collet so as to grasp the radious on it's shaft. Stein.
Andrew,
We recently had the same problem in our shop and discovered that the top of the collet insert over a couple of years had worn down, about a 1/16th of an inch, to the point that the nut could no longer press the insert tightly into the tapered bore, leading to slippage. We replaced both the nut and the collet, figuring that the inside of the nut must also be showing some wear.
If you have a second, less used, collet insert for the machine, match it up against the one that slipped, if the slipping insert isn't as long as the unused one, you will have identified your problem. It can't hurt, in any case, to replace the nut and the insert once in a while, they take a lot of stress.
The tapered outside of the collet insert and it's top edge, that the nut bears on, should both have a bit of lubricant applied after they are cleaned off. These surfaces have to slide against the surfaces they contact, if they bind up, they prevent the collet from seating fully which will lead to slippage.
The threads on the nut also need to be lubricated to prevent binding that would reduce the pressure the nut applies to the collet insert. Lubricating the collet, in addition to making it work properly, prevents wear of the bore and threads on the routers shaft, once either of these wear out the machine can't be used or economically repaired.
For lubricant, I use a stick lube from the hardware store, it looks and feels like a soft bar soap. To prevent getting excess lube on the collet, I use a finger tip to apply it to the metal surfaces, rather than rubbing the stick directly on the metal. Waxes and dry lubricants don't work as well for lubing collets. Our shop routers have been maintained this way for years with no collet problems. The machine with the slippage was a personal one and had never been serviced.
Hope this helps, John W.
I guess you know the collect is shot after the bit slipping its galled- Could have screwed up the cup the collect sits in. If it was smoking that's not good bad bad bad.
I bet you have had a bit slip in it before or it was never tightened enough-
What kind of bit were you using? Are you sure it was the right dia.?
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