Acoustic Guitar Construction

Working on my screw down fretboard extension system.

I have a simple routing jig that I position on the center line.
Cut with a pattern bit the 1 5/8" x 2 5/8" pocket, 1/2" deep.
Then I cut a block of mahogany to fit in the pocket and thin it too about .490" thick so it's just below the top surface when sitting in the pocket. Then I cut out a section that will let the block fit around the tenon.

I realized I was out of the hardware for this, the T nuts and machine screws so I had to order them today. My local HD store used to carry the stainless machine screws I use but no longer for some reason. So more later on this.

You make nice precise work, a joy to watch!
Herman

Well thank you Herman. I try but I sure have difficulties when it comes to keeping everything on the centerline.

Thu Apr 18, 2024 7:20 pm

I'm getting closer to being done on this one.
I wet sanded 600, 800, 1000 and 1500. Then I rubbed the finish by hand with rubbing compound, then polish, then scratch remover.
It's shiny but not as high gloss as when done on the buffing machine using Menzerna compounds.
I don't have room to leave my buffing machine set up all the time so for now it got a hand job. I may still buff it.

I seem to always have some gaps show up along purfling after this stage that for some reason I didn't catch earlier. That is frustrating but at least with nitro lacquer it's easy to fix. I've already done a couple of spots on the side purfling and now I have some small gaps in about 6 places around the rosette purfling.

I usually don't get them on the rosettes, but I used the plastic bwbw purfling left over from my archtop guitar build. I like the nice stark look but used the special glue for gluing plastic to wood and I guess it doesn't have as good gap filling properties as titebond and Fibre or wood purflings that will expand some with the moisture.

Anyway, what I do for these gaps is place pin string tape on either side of the gap...just slightly wider than the area to fill. Then I brush on lacquer over the area. One quick wipe of the brush to float on some lacquer. I leave it to dry and repeat. Usually about 8 or 10 coats will sink in and fill the area just above the tape thickness. I let it dry a couple days the pull the tape and scrape the area flush with a razor blade and sand flush. Blends in and you'd never know there was a gap there. Tedious but works well, doesn't disrupt the rest of the finish and I'm in no hurry.

The frets still need leveling, bridge glued down, tuning machines installed. And probably power buffing.
I'm anxious to hear how she sounds.
I've liked the walnut/redwood combination sound on the 2 I made already.

Good work mate,
Those sags in the purfling area are always a drawback. I too have them on regular basis. I fill them with the used finish just before the final layers. Anyway, fine job. You will figure this out.
Herman

Looks great!

Back on it. I need to finish this one up so I can get back on the archtop and get it done.

So today I set up my buffing machine.

I mounted the neck to the body and made sure it was still on center and the truss rod is adjusted at neutral with a slight amount of tension. It was. Now it was time for the fret work.
I use my aluminum Craftsman level that I bought 50 years ago as my leveling beam. I glue 120 grit sandpaper to it. I
Mark the top of all frets with a black sharpie and work the beam up and down and side to side across the frets until all black is gone from all frets. I remark the tops with the black. Next I recrown with my crowning file leaving a slim black line on each fret. Then I take my safe edge small file and go over each fret to shape up the crown better.
Next I take 220 grit paper and run it up and down the board over the frets which cleans up file marks and helps round over the frets. I repeat with 320, then 600 grit papers, finishing up with 0000 steel wool.

I had 3 frets down on the extension with loose ends on one side so I used CA and a clamp to resolve that.
I also clean up the fretboard surface using the steel wool.

Next I polish the frets using a rotary tool with a small buffing wheel and red Rouge polish. I like doing it this way rather put the whole fretboard against a buffing wheel so I don't get the compound into the fretboard grain.

I buffed out the neck and body on my machine using 2 Menzerna compounds.

Now the fretboard is done. I remounted the neck. This is a bolt on M & T neck with a 2 screw fretboard extension system. Secure but easy removal whenever you need too.

Then I cleaned off the buffing residue where the bridge goes using a 1/4" chisel as a scraper.

I use a Fox clamp for the bridge gluing. I use 2 locating pins in the saddle slot so gluing in the right place is easy now. I have ditched using the 2 bolts on the clamp that goes through 2 bridge pin holes and wing nuts are spun on inside the guitar to clamp it down. It works good but I got tired of fiddling trying to get those wing nuts on as the glue is setting up.......
I still insert the bolts but only to help position the bridge. I use one cam clamp instead for the central part of the jig and get plenty of clamping pressure. Then the wings are clamped down with 2 bolt screwed down against the wings. I use thick leather there to protect the bridge.
Clean up the Titebond squeeze out and there we go.

Back on it tomorrow.