Jared Tulayan

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Luthery Log 4: Milling Mistakes

2022-08-03

#art #guitar #makerspace #woodworking


I got busy over the past couple of days, so this log will cover the past couple of days of work.

First day was spent routing out the body. I got around to making a template in CAD, then using the CNC to cut it out onto 3/4” plywood. I needed it thick enough so that the pattern bearing for the 1/4” bit could run along it. It seemed to work well, though I accidentally milled a little too deep for the last pickup cavity as well as the neck pocket. The pockets all seem to be a little too small to take in their respective parts, but that should be fine with a little bit of sanding/post-process.

At the time of routing these out, I had to wait for some parts to test fit the rest of them, so in the meanwhile, I began milling the guitar neck.

The milling process for the neck is as follows:

  1. Rout out the tuner holes (and screw holes if applicable, but I didn’t have tuners to design in)
  2. Carve the back neck profile
  3. Mill out the truss rod slot, insert truss rod and glue on fretboard
  4. Rout the inlay
  5. Cut the fret slots
  6. Carve the fretboard radius and other neck features
  7. Cut out the neck

I only had time for steps 1 and 2 this night. I ran the roughing job while I was routing the neck plane pockets, and watched the finishing pass. My first mistake was not adding enough padding past the neck in the roughing pass. This caused some issues with the finishing pass, particularly when it moved up to pass over the heel; because it was actually cutting into material since there was no padding, it ended up pulling the bit down and out of the collet. This trend seemed to keep up into the next day.

You can see at the top of the heel and the bottom of the headstock where the router milled into

With some scrap, I just filled in the milled parts. Hopefully the parts aren’t too conspicuous.

The next day I had my Tune-o-matic parts on me, so I used them to test fit the holes and placements of them.

These looked in place, so I went ahead and drilled the holes using a 29/64” (~0.4531” or ~11.5mm) brad-point drill bit. I tried to tilt the drill bit forward for the hardtail holes to make the hardtail lay “flat”, which may have thrown the hardtail slightly off alignment.

Finishing up, I managed to clean up the backside enough to get it onto the CNC and rout out the truss rod. The rod doesn’t fit in yet; it needs some adjustment to get it in, but it is 90% of the way there.

I still need to make an adapter plate for our binding router jig so that we can use our DeWalt router with it, as well as create the inlay designs to mill out both the negatives and the actual inlay pieces. Even with all that, the end draws near. I’m very excited to see what this guitar will look like when it’s done.