Making bridges for vintage guitars using minimal tools
– a layman’s approach (Part 3).
I’ve approached this subject in 4 separate posts. It’s necessary to first read the Introduction post, Part 1, 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 3. Truncated Pyramid Style (or Chicago) Bridge.
Truncated just means ‘shortened’- by cutting off the top of the pyramid in this case. It’s also called a ‘Chicago’ style bridge because it is the bridge Lyon & Healy (one of the first guitar manufacturers based in Chicago in about 1880’s) first put on their early Washburn guitars. Used by many manufacturers including Martin, Weymann, Regal, and Harmony up until about 1930.
For this bridge I also use the 5/8” (16mm) diameter rod for this bridge, which is made from Australian Gidgee timber. It’s the same process used in making the 20th CENTURY PYRAMID STYLE BRIDGE in Part 2. to get it to this stage in these next photos:
A digital Micrometer is a great tool to check all measurements:
In this instance I’ve taken the ‘valley’ of the bridge down to about 3.5mm from the base of the bridge.
The blank I started with was about 13/32” (10.5mm) thick, which generally is a good finished size depending on the guitar. There is room to decrease the thickness from the bottom of the finished bridge if needed, however a good luthier will determine whether that needs doing, or whether he or she needs to raise or lower the saddle during a final setup.
I then will cut about a 3rd off the thickness (about 3mm) from the proposed truncated pyramid section, either with a small tenon saw or similar, or with a small electric band saw:
More careful filing out the saw cuts brings the thickness of the truncated pyramids almost to the thickness I want, then it’s a matter of sanding smooth with the hobby (manicure) sanding boards (along the grain) for a smooth finish. I then mark out the position of the bevel for a 45% taper, or thereabouts:
Next step is filing the bevels:
After a quick sand with 800 grit:
Shaping the main section of the bridge and then polishing the bridge is the same process as with the 20th century pyramid bridge above:
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End of Part 3; Links to the other posts about this subject:
Part 1. Introduction.
Part 2. How to make a 20th century pyramid style bridge.
Part 3. How to make a Truncated (Chicago) style bridge.
Part 4. How to make a 19th century pyramid style bridge.
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I have been doing restoration of old banjos, mandolins, violins and guitars. Neck resets, crack repair, etc., etc. However, making a bridge is new for me. I have the tools to route the saddle slot and have attempted to make my first bridge but it was really bad. Now with your information, I’m sure I can do a better job. I really spent many hours looking on youtube and other sites about making bridges. Yours is by far the best. So glad I found it. I was so excited when I came upon it. I don’t even remember what I googled but just couldn’t believe the exact information was there.
Now I’m sure I can do a better job. I’m going to make the jig and attempt making another Chicago bridge to restore my Ditson parlor. I’ll let you know. Thanks for putting that information part 1, 2, 3 and 4 on the web. You have motivated me to try again and persist until I get it right. Daniel.
Hi Daniel, Thanks for the comment, I was beginning to wonder if what I’d written was useful for anyone. You made my day! Charles