Originally Posted: Fri Sep 24, 2010 1:33 pm
Here's a jig I've just knocked up for my latest builds. Thought I would post it up if anybody was interested in building a similar thing, it doesn't need to be fancy and the advantage is that it's really simple to set the angle & can be 'micro' adjusted to be perfect for slight variances in top to side angles so every neck matches it's top/body.
It's based (copied?) on the neck jig Paul Woolson designed. My previous method to cut the neck dovetails was to have a fixed 'wedge' that was made to the angle I needed & I bolted it to the front of the jig I used to cut the body dovetail.
Here's the old method first with the body in.
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Then with the neck wedge screwed on.
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This was/is ok but as the latest two guitars use a different neck angle again I didn't fancy building up a collection of neck 'wedges' so saw some pictures of Paul Woolson's adjustable neck jig (http://jimsguitarbuilding.blogspot.com/ ... n-jig.html). So I've spent some time since the earthquake building this, it just utilises bits of scrap MDF I had, some hinges I ferreted around for in the odds & Sods draw. It also uses a rack & pinion (to adjust the angle) mechanism I found in my "old decapitated instruments" collection at work but I believe this can be replaced with a simple screw thread adjuster, being an engineer I just like to add something "mechanical"
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It's been abit of a fluid design as I added an extra clamp screw as with just the one up near the top (on the right) & the rack & pinion, I wasn't entirely happy with the stabilty of the neck holding platform. But anyway here's a few more pics. Unlike the one in the linked blog, I decided that I wanted mine to be held to the bench by using the vice already there but also added a small shelf out the back which can be clamped if I ever change benches. I also decided that the blog one was also at too high a working height, I'm only a short arse so the router would be firing wood right into me ugly mug! It's now at a nice working height that I'm over the top of the router.
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I also included a simple guide along the side of the template to keep it on the same centreline (doesn't need checking everytime I move it backwards or forwards). I believe the Woolson rebates the template into the top plate but seemed like alot of extra work to me!
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For anybody that isn't familiar with these, the body is sat on the top (neck joining face down) and the neck holding platform adjusted so that the aluminium 'beam' is at the same angle as the soundboard ramp up to the soundhole.
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This then makes the angle you cut your dovetail or mortice the correct neck angle. I was well chuffed when I measured at the bridge position & a fingerboard sitting between the top & ally beam.... it measured 10mm which I believe is the correct height for the bridge, pre saddle? Gotta get something right occassionally
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