Making bridges for vintage guitars using minimal tools
– a layman’s approach (Part 1).
I’ve approached this subject in 4 separate posts. It’s necessary to read this Introduction post, Part 1, first or the other posts (Parts 2, 3 and 4) may not make much sense.
Part 1. Introduction, tools and a jig.
Part 2. 20th Century pyramid style bridge.
Part 3. Truncated pyramid style (or Chicago) bridge.
Part 4. 19th Century pyramid style bridge.
Part 1. Introduction.
While I am merely a hobbyist when it comes to working with wood, it is something I have done my whole life. I don’t have a lot of specialized tools, but I do like precision, so I try to work out methods of doing things that work for me.
Cutting the ‘valleys’ accurately into the guitar bridge blank goes a long way in determining how well a finished bridge will look. I’ve made probably 30-40 guitar bridges, and when I first started I was not comfortable using a drill or a small sanding drum to make these valleys. I didn’t give me enough control.
So, I made a simple jig to sand the valleys by hand, as will be explained a bit further on in this Post. I’m sure there are many other ways to make these pyramid bridges, so take from these posts what you will. I hope someone finds it useful.
There are many styles of pyramid bridges, and it makes sense to individually craft them for a particular guitar.
In the next 3 Posts (Parts 2, 3 and 4) I’ll demonstrate how I make each of these different pyramid bridges.
But first, some general information about the tools needed and a simple homemade jig I made and use:
Tools: First I need a few things:
Sandpaper sheets; 80, 220, 400 and 1200 grit (or similar gradations) cut length-ways to achieve 3 strips per sheet.
Hand file (I just use a cheap fine metal file).
Fine grade manicure sanding boards which I find good for sanding the pyramid sides after filing. You can buy these at pharmacies or hobby stores. Sometimes I make my own by gluing sandpaper onto strips of ply.
A square, small tenon saw or similar, white pencil (for marking ebony), scissors etc.
A mounted bench vice.
A fixed disc sander or belt sander is handy but not essential.
For shaping the 19th century bridge; a Dremel tool or similar is also handy
For the Jig: Some timber for construction (explained further on), and;
A metal (steel or aluminum) rod, 5/8” (16mm) x 3 feet (900mm) for the 20th century type bridge and the Chicago type bridge, and 1/2” (12mm) diameter x 3 feet (900mm) long for the 19th century elongated pyramid bridge (Martin or Bay State). It doesn’t matter too much if the diameters differ from these, for instance if you have an old bridge you are copying it may have a lesser diameter curve.
A bridge blank; available from stewmac.com, but google other suppliers for the best price.
Jig to cut the valleys into the bridge.
I made this from ¾” (19mm) pine; it allows a rod with sandpaper wrapped around it to sand back and forth. The gaps between the wood blocks are spaced to allow for a 5/8” (16mm) steel or aluminum rod to slide freely.
I screw this (the base) to my workbench, but the end guide blocks could also be screwed directly to the bench, without the base if you find that easier.
The gap between the guide blocks can be narrowed for a smaller 10mm rod (which I use to make the 19th century bridge) by dropping a box over one of the guide blocks on either end of the jig:
The 3mm ply at the base of the gap keeps the rod off the wood base.
Marking out the bridge valley positions.
If you do not have an old bridge to copy, to find the position for the valleys; place the bridge blank roughly in position on the guitar (in a vintage guitar that has 12 frets from the nut to the guitar body, the distance from the nut to the bridge will be twice that distance from the nut to the twelfth fret). Then run a straight edge down both sides of the neck, and allow about 3/16” (5mm) either side where the straight edge intersects the blank.
If it is a standard sized bridge of 6” long, it should work out that there is about a 3” (76mm) clear area for the bridge pins/saddle area, and the ‘valleys’ start about 1 ½” in from the ends. If there are unsightly marks on the soundboard from the old bridge I make the new bridge oversized to cover these.
Some examples of vintage guitar bridges I’ve made over the years:
Well, full disclosure, I made all those bridges except for the last one, the 1930’3-40’s Harmony guitar bridge which was made by my friend, John Davis, of The Guitar Repairers, Brisbane (see CONTACTS page).
End of Part 1: Introduction; If you want to see how I make any of the following bridges click on the link.