Router bit raised by it self?

[keith ouellette]

I have a m12 v plunge router with a router raiser on my table. I set the height and locked it in place.

I made 2 rabbits that were the right height but on the third the bit moved up about 3/16".

Has something like this ever happened to you?

[Anthony Whitesell]

Yep. Been there, done that. I was cutting 1/4" dados with a spiral up bit in an old craftsman router in the aluminum router table, when the bit height increased all by itself. This will happen most frequently with spiral up bits because the shear angle is steep and in the direction of increasing the height. In my case it appears that there was some sawdust in the collet and perhaps the collet itself was not tight enough as it didn't take much effort to break it free.

[Scott Vigder]

Yessirr....I have that router (the M12V) permanently installed in my router table. After running my new edge banding bit I looked down the groove to see it had come up a 1/8" over a 30-inch length.

Turned out I had not tightened it enough...I try to be very careful not to overtighten, but from now on this router gets an extra ooomph from me.

[Dave Falkenstein]

If you are using a 1/2" collet with a 1/4" adapter, the problem is pretty common. The solution to that problem is to buy a 1/4" collet. Or make sure the slots in the adapter sleeve are lined up with the slots in the collet.

[John Thompson]

I've had it happen twice in 36 years. Both cases I didn't tighten quite enough as mentioned. Both cases were with a 1/4 shank as I have never had it happen on a 1/2". Just more shank area to grab by the collect with the 1/2".

And both cases for me were using wide bit diameters and probably just a tad too much depth as in "over-biting".

Sarge..

[Jim McDonald]

I have a m12 v plunge router with a router raiser on my table. I set the height and locked it in place.

I made 2 rabbits that were the right height but on the third the bit moved up about 3/16".

Has something like this ever happened to you?

Yes it has!!! Last weekend, routing 10 ft of 1/4" x 1/4" dado, first pieces went just fine. Next piece, happily routing away when up comes the bit through the 1x I'm routing. Now I have a 2' piece of wood with a 1" deep x 1 1/2 long though hole. E mailed Jointech re the incident he says no way the lift moved, not possible. I believe him. On another forum, I mentioned the incident, consenses on it is not having the collet tight enough. However, prior to re routing another piece, I checked the tightness of the collet and reset the height of the bit. Closer inspection after doing the job was taking the bit out, and finding sawdust in the bottom of the collet. Wether that kept it from tightening properly or not I don't know. just know I'm gonna be double careful next time and double tight!!
Jim

[Doug Shepard]

Yup - had the same problem on a DW621 so I got in the habit of really tightening the collet. So much so that at one point I actually broke the spindle lock:mad: and had to order a replacement. Danged if you do, and danged if you dont. Haven't had any problems so far with my Festool router - knock on wood.

[keith ouellette]

Yes it has!!! Last weekend, routing 10 ft of 1/4" x 1/4" dado, first pieces went just fine. Next piece, happily routing away when up comes the bit through the 1x I'm routing. Now I have a 2' piece of wood with a 1" deep x 1 1/2 long though hole. ....... just know I'm gonna be double careful next time and double tight!!
Jim

Jim; I hope you were using push pads. I never thought the bit would come up on its own. It could have been a bad day for hands.

I thought the collet was tight enough but I guess not. Its 1/2" by the way. Thanks for the replies.

[John Mihich]

My only semi-serious accident happen because a bit raised on it's own. I was using a 1/4" straight cutting bit and running groves in some boards. I noticed the sound change but didn't stop to check - the bit had gone through the wood and hit the palm of my hand - got a small 1/4 cut - could have been a lot worse. I tried the bit again and it happened again (didn't get cut this time - I do learn) - threw the bit away. I was using a B&D router at the time - about 20+ years ago, This was the only time a bit had done that to me, or since - I still have the router and it works fine. Of course it's sort of one of my collectible tools now.

I did have a router fall out of my RT because I forgot to tighten it down after I adjusted it; the bit hit my shoe while spinning - put a hole in the toe of my shoe but did not hit my toe - lucky again. This was a PC690. Not much to prevent it from falling out if you don't tighten it. Don't have that problem now either since I use a lift now.

[Steve Kohn]

I had the problem on a PC 690. Also on a 1/4 bit. Turned out to be the collet was out of round. It was oblong. Replaced the collet and problem never came back.