Cocobolo Custom Bridge for Martin 12 String Guitar

In our last installment, I had taken a shot at removing the tongue brace on the Martin 12 string guitar.  I've also taken a shot at heating the bridge pad with my Brown's Guitar Factory bridge pad heater iron.  The iron was great for the smaller pad on the Epiphone I worked on recently, but it's too small for the pad on the Martin.  I can't heat the whole pad at one time.  I need to come up with something larger.

LMI sells a heat blanket specifically for the larger pads found on the 1970s Martins, but it's pretty pricey, and since I don't think I'm going to be removing a lot of these, I don't want to spend the money.  So I will ponder.

In the meantime, I started to move forward on making a new bridge.  I have the original ebony bridge - it was sanded down at some point clearly to lower the string action.

The guitar also came with a rosewood Martin-style 12-string bridge.  This was probably intended to be the replacement.  And that's my fallback if I fail in my attempt to make a bridge myself.

I have a nice, resonant cocobolo bridge blank I bought from LMI to potentially use on the Gretsch ukulele rebuild.  I didn't wind up using it, so I figured I'd try making a bridge for the Martin with the cocobolo.  I used the rosewood bridge as a template for the curves and wings of the new bridge.

The blank is way too thick on the ends, so I hacked some height off with a coping saw.

I was really liking the cocobolo up to this point. The color is great, the grain is wonderful, it's light weight, and it has a nice, chimey resonance.  The resonance, by the way, is determined using the Crawfish Resonance Method: drop the hunk of hardwood on a concrete floor from a height of approximately 1 meter (about 39 inches or a bit more than 3 feet).  See what it sounds like.

But after sawing some cocobolo I am in love.  The sawdust is wonderfully aromatic - a little smoky, a little spicy, sweet smelling.  Really nice to work with.

 Martin has used a one inch radius on its bridges since the beginning of time...or at least for the last 100 years or more.

To replicate that, I made a jig of sorts to hold the wood up by the amount of thickness I need.  Then I used a one inch (crazy I know) radius spool on the spindle sander.

Worked great.  I was a little concerned that I'd be half-freehanding it, but it came out well.

Here's the blank with the curves sanded.  The lens makes this look like it's a lot wider than the original ebony bridge, but it's the same size.  It's actually a small bit larger - I'll size it as needed to fit the guitar exactly.  And obviously I need to cut the rear contour and shape the belly (top).  But this is encouraging.

You can get a good idea of how nice the grain is in this shot.  should look really good after it's sanded and polished.