Bridges and Nuts

After getting the soundboard fitted into the Harpsichord, it was time to create the bridges and nuts. The difficulty begins with the geometry, first cut a 30° bevel along the face, which is easy enough with either a full-sized table saw (which I no longer have!) or a track saw (which I do). Described in words, the bridge tapers from 3/4″ at one end, down to 1/2″ at the other end, with 2 beveled faces and one 90° face. After that is achieved you then have to bend the bridge (using a steambox – see “Getting Ready for Steam Bending“) to a shape on the plan using a jig to hold it while it dries for a week. This is all described quite nicely in the Harpsichord Project E-Book.

This process for me was not intuitive, but fortunately my mentor was very kind to answer all of my incessant questions. Finally after a bit of trial and error I got the process down and using my mini-table saw I was able to create the 2 bridges and 2 nuts. The problem with the mini saw is that it has a limited overall cutting height, so I had to create a much thinner sled to run the pieces on to cut the tapered faces, as well as to do some hand cutting to complete the cut height of those the saw couldn’t handle. These 2 pictures capture the feel ( a bit) of this process (on a 16″ sample piece). The ‘test’ piece was much easier than the bigger ones. Working with a 55″ piece of cherry on a mini-table saw was quite a challenge.

 

Once the bridges and nuts were cut it was time to apply the plan for the pin block onto the actual pin block, put the nuts in place so they can be accurately positioned when the time comes, then punch the 104 holes with an awl so they can be drilled on the drill press. There are a *lot* of steps involved in building a harpsichord, to say the least!

 

Once the Pin Block was finished it was time to turn attention to bending the bridges.

Completed Pinblock in Instrument

Completed Pinblock in the Instrument

First you soak the bridge overnight in the tub wrapped in sopping wet towels. In the morning it was simply a matter of setting up the steambox and steamer and letting it come up to temperature (about 30 minutes), then placing the soaked bridge into the steamer. I chose to do just the 4′ beech bridge first. It steamed for approximately 30 minutes and then into the jig, clamped and gradually screwed the ‘other’ hardwood (mahogany in this case) holder in place of each clamp.

 

Tomorrow will be a ‘rinse and repeat’ day with the 8′ cherry bridge. Hopefully it will bend as easily as the beech, which bends like butter! The two bridges take about a week to dry in the form (jig) and then will be ready to install onto the soundboard. In the meantime there are a number of other tasks that can be completed so that finishing the soundboard should be able to be done fairly quickly.

 

About npcarey

Amateur Luthier, woodworker, music enthusiast, software enthusiast
This entry was posted in Harpsichord, Lutherie, Woodworking. Bookmark the permalink.

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