Geoff St. Germaine

As promised, here's an update.Looking through my last posts, I've actually made a good amount of progress on the neck.The headstock ears were glued on. In hindsight, I should have done this after gluing on the fretboard extension and routing the channels for the neck reinforcement. I normally use a router table fence for these channels, so once the headstock ears were on I no longer had a surface to properly run against the fence.Here are the headstock ears in clamps.I then glued the fretboard extension on. Nothing fancy here. I used a router with a template bit to cut the 3/16" x 5/8" rabbet for the 5" long extension.Here's the neck with the fretboard extension and headstock ears.I glued in the two 1/8" x 3/8" carbon fiber bars using System Three Clear Coat epoxy. The channels weren't quite as nice as I'd have liked, but the epoxy does a good job of filling those minor wavers in the channel.

Thanks a lot, Pestvic... and Menapia, I'll post updates later this evening. Pros, exactly. Benedetto's book recommends exactly that for the headstock. The idea with the very thin inside finish is to slow absorption or loss of moisture enough to prevent cracking in the case that the instrument is exposed to very dry or (to a lesser extent) very humid environments.

Your back plate carve looks great!

Yeah, I hear you on the top. I am working from Benedetto's book on mine, so I'm using his specs for the top and bracing, trusting that I'll get something both sufficiently loud and strong enough.

Another archtop! Looks great! Lack of volume could be due to a bunch of factors: Top thickness Top stiffness Side depth Body surface area (usually this would have most to do with your lower bout width) String break angle across the bridge (in other words, how much pressure is being placed upon the bridge)

Yeah, every way of doing something has it's downside to account for.

I couldn't tell you the exact mill thickness. The finishing of the interior is as recommended and directed by Benedetto. Since the three coats were sprayed onto unsealed wood, it didn't build very much at all. In fact, even though it was a gloss product it didn't get to anything beyond perhaps semi-gloss. Pros, I've certainly learned the downfall of impatience. Taking twice as long to setup properly undoubtedly saves time over rushing in the long run. Fixing mistakes or redoing work takes up a ton of time.

Yeah, that makes sense with the vacuum press. I imagine as you carved the top with the inside already carved the top would pull down more and more as material was carved away and you'd just end up with a mess.

It's a really good book. For some of the stuff it suggests a couple of ways of doing things. For instance it describes both a hand tool and router method for doing the dovetail. I figured I could do a more accurate job with the router than with saws and chisels, so I went that way. I spent quite a bit of time setting up and measuring to make sure it would work. I was still a little concerned right before I did the test fit with the neck, but it turned out that all the time spent setting up and measuring paid off. Who would have thought?

I got back from visiting my sister last night, so I was able to get back to work on this project. The body is pretty much done at this stage. I have to install the binding and finish sand the body and that's about it. That meant it was on to neck work. The neck blank was a large rectangular laminate of walnut, pau ferro and maple. I cut the headstock angle with my table saw and then cut the rest of the blank out with the bandsaw. Here's the neck blanks as I'm setting it up for the headstock cut. I routed the 1/4" truss rod slot using two bits. I first cut the slot to depth using a 1/4" round nose bit and then cut the two areas for the square parts of the LMII truss rod to fit down into the slot. Next up in the process is cutting the dovetail to fit into the body. This was a little scary as I've never cut one before. Benedetto's book has a fairly elaborate jig to cut the joint. I used a router table and fence. While it worked, I found it to be less stable and I can see the method I used being more prone to an accident where the dovetail doesn't come out perfectly. For this reason I'll be building Benedetto's jig for the next instruments I make. Overall the joint came out very well. It's a very tight fit. I wanted to check the fit and since it's a tapered cut in the body and a straight dovetail on the neck, the joint locks in. The test fit proved very difficult to take apart. I had to clamp a piece of plywood to the body and use another clamp to push the neck out of the joint. I won't be test fitting like that any more, just a simple check at the top part of the joint will be sufficient. Here it is pressed almost all the way down into the joint. The pencil lines across the top of the neck mark the dovetail depth and the line further back is for cutting the rabbet for the fretboard extension. A side view of the joint. The neck is sticks out slightly into the cutaway, but not as much as I would like as it will require sanding the side down slightly to get the neck to be continuous into the side once it's tapered. This will need to be adjusted for on my later archtops. A shot of the dovetail. Overall it's pretty good and will make a quality join with the body, but for later builds I want to have it a bit cleaner so I think a better jig is going to be the way to go. That's it for now. Next up will be cutting the rabbet for the fretboard extension and gluing on the headstock ears and thinning the back of the headstock with my router-planer set up.

Looks fantastic!

Yeah, I agree with you there. Binding the holes on my prototype was a big pain. I was using 0.090" ABS plastic and on the other ones it will be much thinner plastic and wood fiber purfling, so it should be easier to bend.

That looks great Pros. I've seen some archtops with the f holes cut to be 3 pieces so that they close up at each scroll. I thought it looked neat, but the lack of a continuous shape looked a little off. What you have there fixes that concern by having the binding close up, and since the binding is light, like the maple, it retains a little subtlety. I enjoy the design discussions, especially since I'm several thousand miles away from being able to make any progress on any of my builds.

Thanks for the compliments guys. I think my vision is a little myopic sometimes, though. Sometimes more reactionary than well planned. When I originally laid this guitar out with my buddy, it wound up being his call on the f-holes. I had a few templates, including a more curved one, similar to what Framus often used or Benedetto's La Venezia. My buddy went for the more angled one. I thought they both worked in different ways, and I think that the discussion you two have had reinforces that for me. The two archtops I'll be building following my prototype will have more curved f-holes. I'm also likely going to build a couple of follow up instruments to this one and we'll have to see how the design evolves, as I already have some changes planned.

The answer to how it looks is "amazing". Snakewood is gorgeous.

It's glued up into one piece now. I away for another week, so no progress until this weekend. I've roughed out the pickup cavities. I had a template for the cavities, but it's a little on the large side for the pickup rings I have for this guitar, so I'll make up a new one when I get back. Here it is as one piece with the pickup cavities hogged out.

My experience with my first archtop top and back, which both exhibited this cupping, is that the the top/back are so flexible once completely carved that very little pressure is required to clamp down any cupping of the plates to the sides. The sides are so stiff that I can't see the top/back deforming them. If both sides cup in the same direction, then the net force in either direction is going to be very small. I also found that any initial cupping due to carving the outside of the plate greatly reduced once the inside was carved as well. On my top I went from about 3/8-1/2" of cupping at the lower bout (in the same spot as Juntunen's back plate) before carving the inside to about 1/16-1/8" after. I think that makes some intuitive sense when considering internal wood stresses and what would be released by carving out the inside. Juntunen, that back plate looks phenomenal. It would have been a shame to have lost it. I'm looking forward to getting my two "master grade" flamed maple backs started, because the figure is so intense. Great work! I have a question about your neck jig. Does the jig have your neck angle built into it? I'm currently planning out the jig I'm going to build for doing the neck side of the joint and while the Benedetto jig seems nice, it's rather large. While I'm sure it would be great if I was doing a ton of necks, for only doing 3 and maybe a few more after, something simpler that came at the expense of more setup time would be fine for my use.

The inlay is absolutely covering a mishap, good pickup. What happened was the neck tenon is like an LP neck, so it has the tongue under the fretboard that isn't the full size of the fretboard. Shaping the neck joint I carved too deep into the body and exposed the bottom of the neck tenon in a small area. While this did nothing structurally to compromise the joint, the nice straight neck joint now had an area where the maple ran into the cherry and looked rather ugly. My solution was to do this inlay. There's a matching pearl inlay on the back of the headstock, but I didn't get any pictures up of that.

Thanks a lot, Levi!

Those are looking great!

I really like the 3 piece back. Where is the flamed oak going? I really like the look of flamed oak. I have a fretless bass I've built with a 3-tone burst over flamed oak and it's really an outstanding looking wood. Just different enough from flamed maple to look interesting.

I've got a bunch of things done in the past couple of days, to the point that the body is essentially complete. I got some nitro on the inside of the body to seal it. I sprayed 3 coats, which was enough to seal and start building a gloss coat. At that point I considered it to be sufficient to do what I wanted. I decided that it would probably be easier to route the back binding before gluing on the top as the sides still defined a plane that could be easily routed from. It went very smooth, but as I learned from routing the top, it really doesn't make a difference when it's done with my jig. I really like this picture: I glued up the top using my spool clamps. Again, no problems here. I routed the top for the binding, but didn't really take any photos of that. The next task was to route the mortise for the neck. It is a dovetail joint. In accordance with Benedetto's book, the mortise in the body is tapered 1/16" from top to bottom while the neck tenon is the full width so that it "locks in" when the neck is pushed to the bottom. With walnut into cedar I imagine it should be not a lot of trouble to get the neck to squeeze in, but we'll see. I adapted my carving cradle to accept the mortise template. I had to break out some geometry and diagrams for making up the template. I'm using a 3/4" dovetail bit and a 1" brass template mounted in the router so that there's a 1/8" offset between where the template runs and the cutter. The Benedetto book doesn't give specific direction for making the templates to route the dovetail joint, it only describes the process, what to use (3/4" dovetail bit and 1" template in the router) and the dimensions of the mortise and tenon. Coming up with the dimensions of the templates to route against is up to the reader. In the end it worked out fine and I have a mortise that runs 2.5" and tapers from 1" on the outside at the top of the mortise (top plate) to 15/16" at the bottom. My template and the finished mortise: The router with the 1" brass template installed: A couple of looks at the completed mortise: I had a very small amount of tearout at the very top of the joint, but that will be under the neck anyway. Thanks for looking!

The guitar looks fantastic! I think I prefer the look of the solid tailpiece. I'm looking forward to seeing it mounted.

That limba is beautiful and the workmanship looks top notch. I really like how you did the cavity cover, I'm going to try that out on a 1 piece mahogany blank I've got.

Thanks a lot Hitone! I usually don't put as much detail, but since this is something a little more unusual I figured I'd put more detail in to get more critique and help others out if they're thinking of doing one with what did and what did not work. Once this one is done I plan to do a post with just lessons learned and what I'll be doing differently on the subsequent guitars.