DIY TOM Bridge - How much intonation adjustment room?

Corey Y · #1 01-31-2012, 12:40 PM

I'm working on making a tune-o-matic style bridge from scratch for a project. I'm going to use 1/8" thick aluminum U-Channel and I'm trying to figure out what a good amount of space for front to back intonation adjustment would be. The 2 most readily available widths are 3/4" or 1", so 1/2" or 3/4" of adjustment room respectively. The saddles are going to be 1/4" thick and I want to leave a little room in case I want to tune the lowest string down to D. I'm thinking the 3/4" (outside measure) U-Channel should be enough, any input?

Jay2U · #2 01-31-2012, 03:46 PM

In general the length of the lowest string is a little more than that of the highest. The difference between E and G on my bass is only 1/8". The total adjustment room equals about 3/4". If I tune down to D, which I regularly do, I don't need to re-adjust the intonation. The difference is so small that I can't really measure it. If the placement of the bridge is pitch on, 1/2" could be sufficient, but more is safer.

Corey Y · #3 01-31-2012, 04:55 PM

I think I'm going to go with the 1" OSM piece, just to be safe. Better to have and not need and all that. It will give me a little wiggle room on the bridge placement as well if it's more adjustment space than necessary. The cost of the materials to build 4 or 5 of the prototype design I'm using is probably less than even a cheap after market bridge, so I can always refine the design after I get a chance to fiddle with it.

T-Bird · #4 01-31-2012, 10:38 PM

Hi.

The beauty of TOM design is that it can be (and usually is for balancing reasons) slanted, so the width doesn't necessarily have to be all that great. Also, the regular offset-cut saddles that can be turned around will make the whole travel available for adjusting the intonation.

Since the extrusions are cheap, ~10€/kg over here, why not try 'em both, keeping the saddles the same on both prototypes.

Bent steel/brass/aluminium/titanium would look "better" than extrusions though, to my eyes anyway.
Like the ones on early Thunderbird TOM's.

Regards
Sam

Corey Y · #5 01-31-2012, 11:00 PM

Right now I'm using extrusions, simply because of the availability and price. My father also does a lot of metalworking and he's ordering some aluminum extrusions for a project as well, so I'm saving a bit on shipping there. Once I get the concept down I will probably try to refine it a bit and make it more aesthetically appealing. I bought a cheap beater bass to chop up and modify for the project and if I can get everything the way I want I will probably do another build from parts or scratch. It's an unusual octave course setup, so I wasn't able to find anything aftermarket to get the configuration and string spacing I want. I had a far out original top load bridge design concept that I thought about making from 6063 aluminum and then brass if it worked out, but it seemed a little too involved and needlessly complicated, so I brought it back to a more simple concept that I could easily buy parts for and just piece together.

The feedback is appreciated, I'll make sure to post some updates when things move along.