I'm doing a super-inexpensive fretless build using an old Squier body (I know, I know - you can take me to task if you'd like). Alas, the neck pocket is just a bit too shallow, and I need to route it down about 3/32". I have a router, but alas, not the pocket template nor the ball-bearing bit. I'd be much obliged if anyone in this forum that lives near Los Angeles (I'm actually east of LA, near the 57 freeway) could do the quick route for me at their workshop...I can pay a few bucks, or alternatively take you out for lunch. It's a 5-minute job, I just don't have the tools and I'd prefer to not spend $50 on a template/bit for a one-time thing. Plus, always nice to meet a fellow TalkBass member in person! I'm not much of a luthier, it's a project I took up when the opportunity arose. I got the body for free, found the neck for super-cheap on the 'Bay. On the plus side, fretless P-bass! Putting in new electronics and a few simple electronics modifications. I'm quite excited, as I've never owned a fretless and I've always loved playing a naked neck. Got an ebony Allparts neck with one tiny ding near the headstock for a bargain, and the body - though 4 pieces - was free. Stripped it down (poly finish takes FOREVER to strip), gonna be a surf green beauty. Anyhow, if you feel like doing me a kindness, let me know!
You don't need the template just a shallow top bearing copying bit. The pocket is already your template. Stewmac sells one, don't recall the price though.
You can pick up a top bearing flush cut bit from Home Depot for under $30. If you have a straight cut bit all you really need is the appropriately sized bearing and locking collar, but you usually buy those in a set or they come with bits. It'd be more of a chore to hunt down just one. As octaedro7 said, if you're using a top bearing flush cut bit you're running off the profile of the existing pocket and adjusting depth. If you do that you might want to set up some blocks that are even with the surface of the bass though, it's pretty easy to tip the router when you get out to the edge of the pocket on the short horn side. If someone in your area is willing to do it, you could always get the bit anyway and watch them to learn how to handle it yourself in the future. It's always nice to meet new people with common interests in any case.
You don't need a template to make a route deeper. The existing route is deep enough to guide you. I did such a re-route, the objective was to remove the need for a shim by changing the angle of the neck pocket bottom. I used a Strat tremolo back route template that I fixed above the neck pocket. It did not serve as the template, just something to control depth, for the router to rest on. Obviously the angle of this piece decides the angle of the neck pocket bottom. It is very easy to hack into the neck pocket side which would be quite visible, so you probably want to avoid that.
Thanks guys, I tried looking for the top-bearing flush bit at Home Depot and no dice. The only one that the two nearest to me had was a 1" cut length, which was too high. There's a 1/4" shank, 1/2" diameter, 1/2" cutting length bit at MLCS woodworking for $13. I just measured my neck pocket and it should work great. Thanks again!
If you have a router, and decide to do it yourself its not that difficult. I use these bits, because they are extremely shallow. You don't need a template, but you would be wise to build some kind of router support, because there is little wood out towards the end of the neck pocket on the treble side to support the router and keep it stable.