Thread: 2' router bit coming loose during use

When you put the bit into the collet, it only needs to go in about 19mm deep. Dont let it bottom out. Instead of measuring 19mm, I tighten the collar nut by hand until it begins to tighten the collet. Then I back the nut off a bit. Drop the router bit in all the way, then lift it out atleast 4mm, tighten the nut and away you go.

Also, when changing bits, it is a good idea to take the collet and nut off the router completly and remove the dust inside.

thanks for the advice. I can't remember if I did allow the bit to bottom out or not but will give it a go with the 4mm gap.

Cheers

Originally Posted by gtseraf

Hello all.

I have a Triton router and recently used a 2" flush trim router bit (1/2" shank) for the first time.

I was trimming 17mm plywood with it. The bit kept on coming loose after routing about 400mm. I reset it and tightened it again and it did the same. it did this about 4 times, at which stage I decided it was not a good idea to keep on doing this. The bit is a Diablo bit sold by Bunnings. I did tighten it as much as I could and have never experienced this before but have never used such a long bit before.

Anyone have any ideas what could be causing this?

Thanks

I had a similar problem with a Diablo bit when I was helping a friend when he was doing some renovations. He had a set of Diablo bits bought from Bunnings. One of the bits in that set kept creeping out of the collet during use. The bit definitely wasn't being bottomed out in the collet. All other bits in that set, plus a couple of my own bits that happened to be in the car at the time, all held well in the collet on his Makita router.

Next day I bought a micrometer with me and measured the shank on the suspect bit ---- slightly tapered --- about 0.0015 inch undersized near the tip of the shank, tapering to spot on 0.5 inch diameter at the other end of the shank. Poorly manufactured. He took the dodgy router bit back to Bunnings and measured the dodgy router bit and a good router bit while showing the Sales Assistant. They gave him a complete new set of router bits, and let him keep the remainder of the original set. All of the bits in the replacement set had accurately machined shanks. I've also had cause to return a Carbitool bit for the same reason, so occasional lapses in product quality are not solely limited to the cheaper brands.

RoyG

Following a tip on here many moons ago, I have a rubber "O" ring in the bottom of the collet. It prevents the bit from bottoming out.

Originally Posted by Chesand

Following a tip on here many moons ago, I have a rubber "O" ring in the bottom of the collet. It prevents the bit from bottoming out.

That was probably me, not an original as I got it from an old German cabinet maker about 30 years ago.

If you look at how the collet tightens, it not only clenches but actually pulls down slightly, if you have the bit bottomed out to start with then the bit will most probably be stuck to the point where some people have actually been unable to release the collet. The "O" ring trick simply provides a cushion which prevents this happening. It also overcomes the problem of not having 3 hands, hold the bit off the bottom while trying to tightening the collet.