In the last blog post, we made a new nut for our vintage Hofner Colorama II. Also needing doing is an improved bridge.
The original one should've looked like this:
However, here's the (replacement) one I got on THIS guitar:
Apart from looking wrong (not necessarily a big problem), it has the wrong radius, wrong string spacing, and is not compensated in any way for proper string intonation.
The base is almost correct, dimension- and look-wise, so I'm going to keep it and make a new top.
First I get a brass bar:
Cut it to length to match the base:
Mark the position of the holes and hit them with a punch:
Now the tricky part for me, since I don't have a drill press - drilling the holes perfectly straight:
Now turned over to check how close I got. Not bad.
Quick check with the base before taking this any further:
Sides are now marked with a 9.5 radius gauge to match the neck:
The brass is now filed to shape, checking constantly with the radius gauge to make sure nothing is going horribly wrong.
And here's the bridge after that:
The guitar is then quickly strung up (I've been doing a few things in parallel here, so the guitar finish is done now - I'll do a post about that part soon), in order to determine how to shape the top of the bridge to intonate the strings correctly.
First, I put some little pieces of copper under each string. These are actually little cutoffs of thick copper wiring:
Then I check with a tuner and move the copper wires forwards or backwards until the strings are intonating properly, then mark the position with a pen.
After that, I remove the bridge from the guitar and mark it with a couple of lines that will more or less cut through the six marked positions. There's a certain amount of compromising going on here, but it should still end up giving acceptable results.
After that, I start to shape the bridge using fairly fine files:
Giving us this basic shape:
Then I start finishing it, starting with 400 grit sandpaper and going up to 2000 grit:
Finally I hit it with rubbing compound:
For the sides and back, I put the sandpaper on a flat surface and move the bridge itself. Other than that, it's the same finishing process, from 400 grit to rubbing compound.
And here's how it looks after that:
Finally some slots are added to keep the strings in place:
The aim was to follow a similar style to the bridge that would've come with the guitar originally, while correctly compensating it for an unwound G string (the original would've been shaped for a wound G string). I think it came out OK.