Thread: #1 Acoustic Build

Originally Posted by stevemc32

My concern was not with the calculations themselves but with transferring accurate measurements to the fretboard before cutting. How inaccurate does it need to be before I'd notice a problem with the tuning? No idea!

Depends on a few other factors such as the height of the strings and the strings themselves. It is almost impossible to set the intonation for every fret/string. A careful listen will show that guitars are usually fractionally out up and down the fretboard.You can also mess with the tuning by fretting harder and softer. Good players know this and automatically compensate with their technique. How much you hear depends on how good you ear is. You can get really anal about it but personally I think that less than +/- 1/4mm is adequate for most purposes and enough of a challenge to do manually.

BTW templates are beset with their own problems, wear is the most obvious. In terms of machining accuracy I read an interview with Paul McCartney once talking about his violin bass. He complained of it being out of tune on several of the higher frets and apparently it was a feature of these instruments. Ive heard of inaccuracies in early Gibson Mandolins as well.

There is also FretFind 2D which makes a printable fretboard template. I have access to an accurate printer so it works well for me. http://www.ekips.org/tools/guitar/fretfind2d/

Originally Posted by Sebastiaan56

There is also FretFind 2D which makes a printable fretboard template. I have access to an accurate printer so it works well for me. http://www.ekips.org/tools/guitar/fretfind2d/

Great link there, I spent a while on the net looking for something like this the other night, but did not know what to ask the computer, kept getting ,computer says no, computer says no,

Just checked the Stewmac one as well ,Great Thanks,

Originally Posted by Sebastiaan56

How much you hear depends on how good you ear is. You can get really anal about it but personally I think that less than +/- 1/4mm is adequate for most purposes and enough of a challenge to do manually.

I think my ear is definitely a limiting factor here so I'd be happy with the 0.25mm tolerance.

I've cleaned up the bindings and will next be moving onto fitting the neck. Haven't bothered filling the binding gaps just yet, see how I feel about them before finishing. The bindings did get pretty thin on the back around the waist but I can live with that.

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Worked on getting the correct neck angle set this afternoon as well as sorting out the dovetail routing jig.

Here's the setup used to get the neck angle set. Basically just putting it together and making adjustment cuts to the base of the neck on the bandsaw until it lined up properly.

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Did a dry run on setting up the routing jig to check if I could line it up ok and the clamps would be sufficient. Unfortunately it was close to 8pm when I got it all in order and the neighbors were enjoying dinner in the yard so I decided to hold off on firing up the router...

Here's the jig ready for the guitar body to be clamped in.

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Guitar is looking good Steve, dont they look great with a neck after playing around with a box for months? I like the stack of tone woods at the back of the picture as well, would like to see more pictures of your jigs at work,I want to build some but am feeling a bit to tight to buy two bits of acrylic sheet for seventy bucks, and was thinking of cutting the templates out of brass sheet.

Thanks Rob, it is good to see it looking like a guitar!

Here's a few more photos of the dovetail routing. The first one shows the box clamped into the jig. The second was a half cut just to test things out and see if it was working. The third one shows the completed cut.

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You can notice in the second photo a lot of burning at the top of the cut, I found that I'd set it about 1mm deeper than the actual size of the router bit so it had a little bit of trouble at the top there. I'll clean it up and shouldn't be a problem.

I have however found a real problem that I'm not sure is recoverable. Getting the neck ready for clamping into the jig I noticed that it has quite a twist along it's length. I'd seen this before at the headstock but thought I'd just misaligned the headstock a little when gluing it up. Unfortunately, the sticks don't lie...

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So do I try to fix this up or should I just start again on the neck? I figure there's a few things I could try - run it over the jointer or belt sander or try to square it up with a handplane but I'm not sure how successful any of these would be. I'd hate to have to scrap it as I'd no longer have a headstock plate to match the fretboard and bridge.

Construction has ceased for now. Any ideas?

If it was mine I'd get some of the same neck timber and laminate it on with 5 minute Araldyte.First I would plane out the twist., then stroke on a flat board with 80 grit then glue down the new bit and finish up at the right dimensions till it just tapers out at the nut point, I have forgotten you neck timber, is it Aussie Hard Wood ? if well matched you wont see it on the sides and your fret board covers the worst of it, then you can still have that neck glued in asap .
just make sure the new bit you glue on from the side, that the grain is a parallel match, and look at the end of your neck to see which direction is the heart of the tree, and do the same on the patch if you can.Rob

Hadn't thought about hand sanding it on a flat sheet. Might go try that now.

Not sure I'll need to laminate another piece on since I haven't done any final shaping hopefully it will still fall within tolerance.

Thanks Rob.

So who's the big drama queen?

Ten minutes with some sandpaper stuck to the tablesaw top, a little stroking, and the twist is gone from the top side of the neck. There is plenty of timber left at the heel to cover the new alignment however the headstock is still just slightly off. Back on track. Thanks Rob.

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I made some modifications to the routing jig so the neck could be clamped on and its time to get it mated up to the body.

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This is as far as I got unfortunately. I trial fitted the neck to the body and found the tenon was still a little large to get the neck fully into the body so was realigning the neck on the jig when work phoned and cancelled this afternoon's shed time...

Hopefully have it fitted up tomorrow.

Finished off routing the neck joint this morning. I left it just proud of a flush fit as I was scared of going a bit too far with the router and will finish off final fitting with the hand tools once the heel has been shaped.

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Here's the heel, shaped up ready for the neck fitting.

Looks good Steve, the jig's worked well,the acrylic sheet looks like 10 mm thick ? It's lucky you cut the neck out when you did and it settled ,rather it happen once glued in, Rob

Spent some time fitting the dovetail neck joint today and managed to get a satisfactory result. I did need to take quite a bit from the shoulder on one side to get the neck lined up properly so a small shim was required on the dovetail tenon.

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I think next time I won't bother trying to get such a close fit with the initial routing as it required quite a bit of adjustment anyway and would probably have been easier with more material to work with on the tenon.

Once the fitting was complete I roughed out the headstock shape and completed the initial shaping of the neck before committing it to glue and clamps.

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