# bit slipping deeper on a groove



## cegaton (Sep 19, 2010)

I've been trying to rout some simple 1/4" wide and 1/4" deep grooves along long rails to mount panels. I use a 1/4" straight bit on a Bosch Colt Router. My concern is that a couple of times I've experienced the bit going deeper and deeper as I move through the piece (I can hear the different sound and feel the feed to be harder and that's when I stop). How can I prevent this? I'm worried about the bit coming loose and causing an accident. The router is just a few months old and I replaced the collet just to make sure it was not defective or something, but I get the same issue. At first I thought the problem was because I was drilling to deep in a single pass (1/8" deep per pass) so I decided to make more passes and increasing the depth more gradually, but I got the same problem. Is this happening because the bit is touching the wood on both sides of the groove? I've cut wider dados in the past with no problem...
Any ideas?


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## jschaben (Jun 21, 2009)

cegaton said:


> I've been trying to rout some simple 1/4" wide and 1/4" deep grooves along long rails to mount panels. I use a 1/4" straight bit on a Bosch Colt Router. My concern is that a couple of times I've experienced the bit going deeper and deeper as I move through the piece (I can hear the different sound and feel the feed to be harder and that's when I stop). How can I prevent this? I'm worried about the bit coming loose and causing an accident. The router is just a few months old and I replaced the collet just to make sure it was not defective or something, but I get the same issue. At first I thought the problem was because I was drilling to deep in a single pass (1/8" deep per pass) so I decided to make more passes and increasing the depth more gradually, but I got the same problem. Is this happening because the bit is touching the wood on both sides of the groove? I've cut wider dados in the past with no problem...
> Any ideas?


Hi - Welcome to the forum
Is the bit slipping down in the collet or is the depth lock slipping? 
I've had an occasional problem on plunge routers where I haven't tightened the depth stop rod sufficiently which gives a similar problem. I know the colt isn't a plunger but it does adjust vertically as opposed to rotating the motor.


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## BrianS (Nov 7, 2004)

Any chance you are putting the bit too far into the collet before tightening? If you don't raise the bit at least 1/8" from the bottom, the collet can't tighten properly and will often work loose.


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## bobj3 (Jan 17, 2006)

HI cegaton

The error maybe with the bit they are not all made the same,or you are using a 6mm collet on 1/4" shank bits..if you have replace the collet I would say the bit is in error..the collet can only hold what's it's made to do..

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cegaton said:


> I've been trying to rout some simple 1/4" wide and 1/4" deep grooves along long rails to mount panels. I use a 1/4" straight bit on a Bosch Colt Router. My concern is that a couple of times I've experienced the bit going deeper and deeper as I move through the piece (I can hear the different sound and feel the feed to be harder and that's when I stop). How can I prevent this? I'm worried about the bit coming loose and causing an accident. The router is just a few months old and I replaced the collet just to make sure it was not defective or something, but I get the same issue. At first I thought the problem was because I was drilling to deep in a single pass (1/8" deep per pass) so I decided to make more passes and increasing the depth more gradually, but I got the same problem. Is this happening because the bit is touching the wood on both sides of the groove? I've cut wider dados in the past with no problem...
> Any ideas?


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## cegaton (Sep 19, 2010)

jschaben said:


> Hi - Welcome to the forum
> Is the bit slipping down in the collet or is the depth lock slipping?
> I've had an occasional problem on plunge routers where I haven't tightened the depth stop rod sufficiently which gives a similar problem. I know the colt isn't a plunger but it does adjust vertically as opposed to rotating the motor.


I'm positive it's the bit that is moving, the rest of the router stays the same.
I have yet to try a new bit...


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## cegaton (Sep 19, 2010)

Both the collet and the bit are 1/4". I guess I'll go buy a new bit and make sure it raisedis a few mm ...
Thanks for the help


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## dutchman 46 (May 23, 2007)

Check the bit for burns, or scratches. The tool will not hold a bit that is damage. The other thing I heard You say is drilling. Be aware that the router bit has flukes that are sharp, and cut a nice path when You rout.


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## Aquadan005 (Sep 11, 2010)

dutchman 46 said:


> Check the bit for burns, or scratches. The tool will not hold a bit that is damage. The other thing I heard You say is drilling. Be aware that the router bit has flukes that are sharp, and cut a nice path when You rout.


Sharp Flukes? Are they spicy flounder? :sarcastic: Or did you mean flutes ? :laugh:


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