Cavity Routing Question

[wolfcoast]

Ok I did a search but couldn't find exactly what I was looking for.

In the middle of my first build and running into a small problem regarding control cavity routes. I routed the cavity as far as I think I can go with my router (depth wise). When trying to install the volume/tone pots, there is not enough of the pot shafts sticking out to allow installing the nuts to lock them into place. I've tried adding some depth with a forstner bit but it ends up making the cavity look like crap since the pots are very large and it takes more than one cut with the forstner bit to enlarge the area enough.

So the question, how much of the shank of a router bit needs to be in the collet to ensure safe gripping of the bit? I would like to extend the router bit as much as safely possible to increase the depth of the cavity.

For informational purposes, I have the standard Stew Mac Alder body blank and am using Pots from Stewmac.

Thanks in advance.

[Supernova9]

Ok I did a search but couldn't find exactly what I was looking for.

In the middle of my first build and running into a small problem regarding control cavity routes. I routed the cavity as far as I think I can go with my router (depth wise). When trying to install the volume/tone pots, there is not enough of the pot shafts sticking out to allow installing the nuts to lock them into place. I've tried adding some depth with a forstner bit but it ends up making the cavity look like crap since the pots are very large and it takes more than one cut with the forstner bit to enlarge the area enough.

So the question, how much of the shank of a router bit needs to be in the collet to ensure safe gripping of the bit? I would like to extend the router bit as much as safely possible to increase the depth of the cavity.

For informational purposes, I have the standard Stew Mac Alder body blank and am using Pots from Stewmac.

Thanks in advance.

How much extra depth do you need? What length is the cutter you're currently using? Ideally I wouldn't move the router bit in the collet at all, at very most maybe 1/8". Get a longer router bit, it'll look cleaner and you'll prefer the finished result, I'll bet.

[gripper]

I use a razor knife and a sharpened bent screwdriver to get the last 1/8" of depth cleaned up. Keeps me from going too far too fast also. I cut a clean edge around the inside of the route with the razor and scrape from the center to the razor cut with the screwdriver. Takes time but poor folk got poor ways. Razor knives ROCK!

[unclej]

So the question, how much of the shank of a router bit needs to be in the collet to ensure safe gripping of the bit? I would like to extend the router bit as much as safely possible to increase the depth of the cavity.

remove the nut and collet completely from the router. place the nut over the shaft of the bit and then place the collet over it. when the end of the shaft is even with the bottom of the collet replace the whole thing and tighten very well. that's your safest minimum depth.

[Guitarfrenzy]

I ran into this same problem when I was first starting out. It's a very good question you bring up. From reading articles like this one, you will find it best to insert the shank into the collet all the way, then pull it back out about 1/16", and that's your optimal router bit position. Some others might suggest similar ways, but whatever works for you. It's really not safe to let only a small portion of the shank be held by the collet, for a number of reasons.

- Your introduce warble into the rotation of the bit and it won't work as accurately.

- It's dangerous because the bit can fly out harming someone.

- Tightening up the collet with only a part of the shank inserted will damage the collet over time.

Believe you me, it's much better to just buy another bit that's longer. I basically use three cut lengths for flush trim pattern bits, which is a 1/2" cut, 1" cut, and 1-1/4" cut. You can never have enough router bits, and using a router bit in an improper manner can get you in trouble, I consider myself lucky when the bit flew right over top of my head. Never again did I take chances with trying to get more cutting length out of a bit. It's designed for that amount of cut, so be safe and buy the appropriate sizes. Good luck..

Matt Vinson

[Southpa]

Stewmac sells long shaft pots.