Stay in Tune vol#61
By Luthier Patrick Podpadec
I had to build a few bridges this past week. Most of the time I will have to replace the standard“Martin” style bridge (the most common style found on acoustic guitars). Occasionally you will come across different styles and it is good to have some knowledge on how they are cut. This past week I had two challenging bridges to make. The first one is called a “pyramid” bridge. This style is typically found on older prewar instruments,although many newer reproduction guitars are using this style too. This bridge gets its name from the “wings” of the bridge having pyramid shaped ends. They are a bit more difficult to shape due to the sharp angled facet cuts that make up the pyramid. It is important to cut each facet of the pyramid in the right succession for maximum accuracy. As long as you don’t make the cuts too deep,you should be alright. It does take a steady hand and a bit of practice. I was able to cut a very nice sharp edged pyramid by just using a sharp file. It didn’t take very long at all. I had to be careful to not to rock the file too much because it is easy to cutaway too much and then you’ll find yourself swearing a lot and having to start over. I used a very nice piece of Brazilian Rosewood from my private stock so I did not want to be doing it twice. The other bridge was a pinless style bridge on a 12 string guitar. This means that there are no holes drilled through the top of the guitar and no bridges pins to break, loose,or get stuck. That all sounds good, but this type of bridge has its faults too. By attaching the strings directly to the bridge and not the body of the guitar you are constantly pulling the bridge off of the top with over 200 lbs of pressure. It usually doesn’t take too long (approx1-5 yrs) to loosen itself from the top. It also could take some of the top with it when it goes. What most companies do is try to fix that design flaw by adding another. They decided to put screws or better yet, nuts, washers and bolts. So even if it comes unglued or warped it probably won’t come off (unless it breaks on the grain line that the holes for the bolts were drilled, which it always does). As you can tell, from a repairman’s point of view,I feel this style of bridge has the potential to be problematic. I have seen some successful pin bridges, just not too many.
After a mad dash to get 5 or 6 instruments done for Christmas I have been rearranging my new shop in the past few weeks during the holidays. Building benches and setting up tools is probably the most fun for me. Of course I’ve changed my mind (or maybe I just “rearranged” my mind) a couple different times now to decide the best location for this machine, or the lighting needs to be brighter for that, and “Gee I sure could do a better job if I bought one of those”! I guess I’ll just add that to the new set of goals that I have set out to accomplish. The list is getting pretty big and the first week of the year over already. I better hurry up and get back to business. One more quick wish for the new year.... Stay in Tune!
Patrick from Liam Guitars / Wood-n-Strings