Here’s something you don’t see every day:
The story is that a former cellist started playing guitar, and it just felt more natural to play the guitar vertically. Someone helpfully installed a cello endpin, but unfortunately didn’t do it correctly, and the pin was very unstable and wobbled all over the place. Now, I don’t typically work on orchestra instruments – I send all those inquiries to the good people at Keller Strings. But this particular job blurred that line, and I thought it would be a fun project to take on to break up my normal routine of tons of fretwork.
As I don’t work on orchestra instruments, I had to figure out why this thing was unstable in the first place. I think perhaps the gaffer’s tape may have been a clue:
Cello endpins work on the same principle as acoustic guitar endpins – they are tapered, and fit into a tapered hole. There’s lots of contact, and that makes for a very stable connection without using glue. Unfortunately, the person who did this modification didn’t take heed of this, and just drilled a un-tapered hole in the guitar’s end block (and also drilled it off center and misaligned):
The cello endpin wasn’t making much contact in there, and it’s no wonder it was wobbling. I was going to have to plug the hole and ream a new tapered hole. This was to be more complicated that it sounds. Since the original hole was misaligned, I couldn’t just shove a wood dowel in there – there wouldn’t have been enough wood on wood contact to be a strong bond. I was going to have to cut a new hole. Here’s where things got tricky: the hole is really big – 3.5cm in diameter. Even if I had a drill bit of that magnitude, it would just end up following the bad trajectory of the original hole. I would have to use a router.
First I had to make a routing template for the correct size hole. I wandered down to the new art supply store that just opened up down the street, looking for ideas. I found a circle inking template, which had a circle the exact size I wanted. This was just a thin piece of plastic, but I thought if I were very careful I could make it work. I cut out a thick piece of clear acrylic, marked it out, and taped the circle template to it.
Then I very carefully cut out a perfect circle, using a follower router bit which rolled along the template. Success!
Ok, so now I had my circle template that I could use safely with the router on the guitar. I had purposely oversized the template by a few millimeters, so I could use a collar on the router to ensure a safe cut on the guitar (I don’t fully trust follower bits, as the follower bearing can sometimes seize up and ruin the template and the route). I would only get one shot at this, and I wasn’t taking any chances. First, I tested the route in a scrap piece of wood, and the dowel fit in it perfectly, so it was time to set up the guitar for routing.
I somehow had to set up the guitar upside down, so I strapped it to the side of my bench. It looks funny, but it was super stable. I attached the routing template over the original bad hole, took a deep breath, and routed my new hole:
Huzzah! Perfect! Next, I made a plug and glued it in, and carved it flush to the body.
Now all I had to to was ream a tapered hole for the end pin. When I looked into how much a reamer for this size cost, I just about choked: $500! I don’t have a problem with buying tools and losing money on a job, as those tools will eventually pay for themselves down the line. However, since I don’t think I’ll ever install a cello endpin into a guitar ever again, that seemed foolish. Fortunately, my friends at Keller Strings allowed me to use theirs at their shop. Thanks Paula & John!
The endpin now fits perfectly, and is super stable – doesn’t wobble at all. Hooray! I put a lot of time into this job that I wasn’t going to get paid for, but that’s ok – sometimes having an interesting challenge to overcome is more important than making a profit. If this job weren’t fun, I wouldn’t be doing it!
