Sunday, December 13, 2015

Day 107: The Pinblock Cap

While I've come to learn there's real danger in not following Mr. Miller's instructions to a T in his eBook Most Excellent, I still strike out on my own from time to time with varying degrees of success. The next step I should have followed in the book was to prepare the sides of the case for gluing. A lack of funding in the weeks before Christmas have prevented me from accomplishing this (yeah, I can't afford the quarter sawn red oak veneer for the sides until after the holidays), so I looked around the shop and realized I had the materials to start the pinblock of the instrument.

The harpsichord pinblock, or wrestplank, is a thick piece of hardwood that holds tuning pins for the instrument. As such, it must be sturdy and solid, so I will be following Mr. Miller's advice and making it from red oak. There is, though, a cosmetic consideration that requires me to cap the piece with quarter sawn spruce to match the soundboard when I get to that part of the project.

Fortunately, I happened to have some fairly nice Sitka spruce in stock that I had picked up at Woodcrafter's for $6.95 a bookmatched set. A couple of flaws prevented these from being used as, say, guitar tops, but I knew I could someday use them for guitar bracing or for another, unforeseen, purpose. In this case, I was able to cut them up in a way that eliminated the flaws. I started by running the side edges through the jointer.

Once they were cleaned up, I ran them through the planer, leaving them a little heavy for later hand planing and card scraping down to 1/8" (3mm) thickness.

They looked pretty nice once I planed and scraped them down.

The next step was to straighten up the ends. Both ends needed it, which I completed on the table saw.

Once that was done, I went ahead and cut them to a width of eight inches so that the grain ran front to back along the short side. You can see one of the flaws in the photo below that prevented these pieces from being used as guitar tops.

These are the pieces laid out as they will be glued together and then mounted to the top of the wrestplank.

I then broke out the trusty, old guitar top gluing jig. This jig simultaneously pulls the pieces being glued together along the horizontal plane while also keeping pressure on the top of the piece so they don't buckle and ruin your day.

I have never gotten the hang of making perfect figure eights with the twine. I see guys using their jigs on Facebook and their twine and wedges look orderly and beautiful in a utilitarian sort of way. There's nothing orderly or beautiful about my jig, but, hey, it works. At least I get the utilitarian part right.

I glued the pieces using the jig in groups of two. Once they had dried for a couple of hours, I went ahead and threw them under some pressure for the final glue up. The resulting jointed piece will be 8" x 33", which will be cut down to 7 5/8" x 31 1/8" when glued to the wrestplank.

Yes, we use only the latest high tech clamping equipment at Tortuga Early Instruments Worldwide Headquarters.

Once I get the final joint planed and scraped to my satisfaction, I'll pick up the oak to work on the foundation of the wrestplank; it will be an 8/4 (2") piece that I'll work into shape for the mounting of the cap and final sizing.

Until next time...

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