Drilled a 1/4" ground wire channel from the bridge to the wiring cavity last night and was wondering how you all avoided some issues???

#1. How do you keep the drill bit from "wandering" or bending when driving into the wood at an angle???
#2. How do you begin to get the drill tip into the wood without it "walking" or travelling over the surface of the bass???

The channel for the ground wire found its way into the routed wiring cavity without boring through the bottom of the guitar...
However...
It was about 3/8" from my inteded finishing point; (pretty close to the bottom of the wiring cavity)

A 1/4" bit should be fairly stable, but one thing you have to remember is let the bit do the work. Don't put tons of pressure on the drill, that would make it pretty easy to bend your bit. Just go slow, make sure you pull out every once in a while to allow the wood chips that are building up to clear out of the hole.

As for keeping it from walking, a lot of people used what's called a scratch awl, (http://www.woodcraft.com/family.aspx?FamilyID=429) where you use that to make an indentation exactly where you want the hole to be and the bit will usually follow that well. A scratch awl doesn''t have to be anything fancy, it could just be an old beat up screwdriver that you grind to a point on the end. Oh, and I usually put down some kind of protection on the top (like my scraper) to make sure can't dig into the wood.

That's just about what I figured...
Less pressure, clean the cavity/bit, and protect the surface...
How do you estimate the angle the bit should enter at???
I used "guestimation"...
Without a protractor and compass, my geometry falls into the crapper...

I had some bad experiences with a 1/8" bit, but I have done just fine with a 3/16. No trouble with it wandering/bending. I guess just slow and steady.

Another option is to drill from the neck pocket through the pickup cavities and under the bridge. Then drill down under the bridge to meet that hole. It's just a short hop from the pickup cavity to the control cavity, and less danger of wandering. Basically, run everything through the bridge pickup cavity first.

Long 1/4" brad-point bits are available at most hardware stores.
I`d suggest picking up one of those.

Another option is to drill from the neck pocket through the pickup cavities and under the bridge. Then drill down under the bridge to meet that hole. It's just a short hop from the pickup cavity to the control cavity, and less danger of wandering. Basically, run everything through the bridge pickup cavity first.

...and if the bass is a neck-thru?

...and if the bass is a neck-thru?

.... well ... yeah. That won't work.

Just trying to get some out-of-the-box thinking going on. There are often other ways to do things.

Through the neck rout...
That's an option as well...
Thanks!!!

I drill a small hole under the bridge just a 1/4" with a drill press then start my angled hole in that hole so it can't wander. Hope I described that ok?

I drill a small hole under the bridge just a 1/4" with a drill press then start my angled hole in that hole so it can't wander. Hope I described that ok?

+1

tjclem and Greenman,

makes perfect sense...

Is there any "science" to guestimating the angle for drilling???

tjclem and Greenman,

makes perfect sense...

Is there any "science" to guestimating the angle for drilling???

Usually I almost lay the drill down on the bass.

I built a small jig to "measure" the angle and stabilize entry. I took a block of maple about 4" by 4" by 2 1/2". I glued a piece of heavy felt to the bottom to protect the top of the instrument. I then figured how long the channel was going to be, and how deep in the control cavity I wanted the exit hole. I drew a little picture, and that gave me the angle I was going to want to hit the top at, sir.

I chucked a nail in my drill press vice, and a long 1/4" bit into the jaws. I aligned the vice so the tip of the drill bit met the point of the nail.

I carved a tiny flat spot on one bottom edge, and used my stupid little drawing to figure where the bit would have to enter my jig in order to exit at the edge, and maintain the correct angle so I would hit the right spot in the control cavity. I carved a little hollow at that spot for the bit to enter.

I impaled the flat spot (exit hole) on the nail chucked in the drill press vice, and aligned the end of the bit with the intended entry hole. I drilled that hole, I did, and it felt pretty good.

When I want to drill a channel from under the bridge to the control cavity, I scratch a little dink where I want the drill bit to enter under the bridge. Then I slide the aircraft bit into the jig with the point not quite protruding. I place the jig onto the instrument top, and "aim" the bit at the target spot in the control cavity. When I have the exit hole on the jig aligned over the intended entry hole in the top, I slide the bit out until it just tastes the awl hole. You can feel when it is properly aligned.

Holding the jig in place, I remove the drill bit from the jig, and clamp the jig in place on top of the instrument. Now I chuck the bit in a portable, and slide it into the hole in the jig. I drill that hole into the control cavity, man, and this time it feels even better than the last time.

You can make one of these jigs in less time than it took me to write this. I'm going to go have a smoke now.

The picture, in case that didn't make sense to anybody, is what I believe is called a right triangle, with three sides, and one 90 degree angle. One of the sides adjoining the right angle is the distance from the intended entrance hole in the instrument top to the lip of the control cavity, directly over the intended entry point. The other side adjoining the right angle is the length of the distance from the top of the instrument down to the intended hole in the wall of the control cavity. The other side, you don't have to worry about, unless it is longer than your drill bit. Then you need a longer drill bit.

Cut out this little triangle, and hold it against the edge of your jig with the hole on the botom edge of the jig (the exit hole) aligned with the point of your triangle where the entry hole in the top of the instrument is. Use it to determine where on your jig the entry hole has to be. Sorry if this is not clear.

Take your time when you start your final entry into the instrument top, so the bit achieves the proper angle and doesn't deflect too much.

tombrien,

thanks a ton!!!
it makes perfect sense to figure out the angle with a drawing and then align it with the created jig...
talk about being resourceful...

Thanks again...

Usually I almost lay the drill down on the bass.
damn close

If you're only doing this once, or you don't want to bother with the jig for any other reason, grab a 3/8" bit, and drill a
hole about 1/4" deep at the intended entry point under the bridge, straight down into the top. Now when you prepare to drill your channel, your sharp 1/4" aircraft bit can bite into the side of your pilot hole, instead of trying to penetrate a hard top at an acute angle. This is not quite as neat as using the jig, but not by much!

Always use a sharp bit, and even for the pilot, which is an easy shot straight down into the top, use the awl to put a little target hole at ground zero. Makes it a little easier!

3/8" pilot hole, 1/4" deep...
Noted...
what type of protection do you use on top of the bass when not using the jig???
I was thinking of using a piece of that mesh shelving cover underneath a thin piece of stainless steel to keep the bit from "etching"...

Just throwing another idea out there. This works only if you're putting a top on your instrument. Just make a template of where you want all your wire cavities to run, and use a router to make the path on the body blank before you glue the top on. Then glue the top on, rout out your cavities and bam, the paths for the wires are already there. Probably the best way to do it if you're building from scratch.

On my first build, I forgot to drill the hole from my neck pocket into the bridge pup... so I had to do a long shot starting from INSIDE the control cavity, drilling into the bridge pup cavity, then through to the neck. Man, was that scary!

And just another idea, kind of a last resort thing. If you had to, you could drill in from where your strap button on the bottom of the guitar is going to be, straight through your pup cavities. Then down to the control cavity. Have to have a good steady hand and be able to keep that drill level for that one though!

As for determining the angle... it's mostly just by eye. I basically try to lay the drill down as low as I can without chewing up the top!

I started using jigs for just about everything these days. It only takes a short time to fabricate one, and if you are constantly drilling the same holes, the jig cuts set-up time down a lot. A little 2" square block of lexan, plexiglass, or maple with felt on the botton keeps everything as straight as possible, and for me, it speeds up a lot of processes. I have enough scrap to make as many as I need!