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Hi Everyone!

I’m currently working on my 2nd and 3rd guitar builds and I am at the point where I have to route the mortise and tenon. I’m having issues figuring out the neck angle that is appropriate for each guitar. The angle from the top to the sides where I’m routing the mortise is not 90 degrees. How should I go about establishing the correct neck angle to cut into the neck blank? I’ll be using the elevate lutherie M&T neck jig.

I’ve included some photos. Thanks in advance for any tips.

All the best

Carlos

Generally on steel strings with a standard 25' radius top the neck tilts back at about 1 1/2 degrees. That's where I always start and then there'e a little fine tuning after the mortise and tenon are cut.

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Agreed. I think Elevate expects the neck angle is already milled in before using the jig and 1.5 degrees should get you close. There is also an hour long video from Beau Hannam using this jig which might give you some ideas - https://youtu.be/mYWfTd3TFCM?si=ZjcoRtVyeX4cs0OZ


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Some good advice given. I use a Simpson jig that I picked up at an OLF auction way back when. It certainly makes it simple.
https://youtu.be/v-uILpnd9kw?si=D46IjtNIeL8VvYcC

Thank you for the responses. Both guitars do not have a 90degree angle from the top of the guitar to the side where I will be cutting the mortise. Is that typical or should I have made that perfectly 90 degrees?

Very typical.

This will give you exactly the angle you need. The black arm was taken from a bevel angle transfer tool. The piece at the heel block is a fingerboard cutoff. I like a ruler on the fretboard to clear the bridge by a little. The bridge isn’t carved yet and will end up thinner than the blank and the frets will raise up the string plane a bit, too. You can adjust as desired.

I do pretty much the same thing. Use a shim at the headblock the same thickness as the fretboard and tape your bridge in the proper location. The long goniometer should clear the bridge by whatever amount you expect the neck to move under tension.

For me with a double tenon bolt on neck it’s about 1/16” without frets. I tape a 1/16” drill bit to the front of the bridge and shoot for the goniometer just touching it. A glued dovetail and extension would move less in my experience.

Transfer the angle to your tenon routing jig. I think if you error it’s better to be slightly underset as it seems easier to increase the neck set by flossing than decreasing it, especially after the fretboard is glued.

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Very clever little tool there Bob!

Nice toes, btw…;)

Thank you!

Bob, would that method be in the ballpark range of the 1.5degrees or should I not worry about the 1.5degree with your method?

1.5 degrees is a reasonable guess when you don’t know. The method I pictured gives you the angle you want taking everything into account. It’s as close to reality as you can get. I use the device to transfer the angle to the miter gauge on my disk sander where I sand the end of my neck blank to the angle. Measurement is never perfect and some adjustment is usually required at the final fitting.

Thank you Bob! That makes perfect sense. I just hope I marked it correctly. I’ve attached a few photos. Does the way I’ve done it look right to you?

I placed a 1/4” piece that represents the fingerboard at the heel area and a 3/8” bridge at the correct position for the scale length(24.9”)

P.S. I appreciate the help from all of you very much. I don’t have much woodworking or guitar building experience so it helps me out a ton when you folks give me advice.

Yep. It’s that straightforward. Since this is the first time you’ve done it, you might want to make up a dummy neck out of scrap wood and work through the process with that to see what problems you encounter. If your first try with the scrap wood ends up being perfect, then you will have wasted all of that extra effort and a piece of scrap. Or, you could solve some problems you hadn’t anticipated and save your good neck wood.

Note that addressing the centerline alignment is a separate issue. Sometimes the heel block in a completed body isn’t exactly at a right angle to the centerline of the guitar. With a dovetail joint, usually you address that alignment by sanding the cheeks in the final fitting.

Nice looking body.

I tried it on a scrap piece of mahogany and got these resulta. When I put the straight edge the scrap piece does not sit flush with the straight edge. The straight edge should be sitting flush correct? Or should the straight edge be flush when removing both the the 1/4” piece and 3/8” bridge? What method is used to make sure the cut is correct?

I know I’ll be working to get ur spot on after I cut the tenon and fit the neck to the body.

Thanks!!

Put a 1/4” fretboard proxy the whole way up the fake neck now instead of just at the block. Put your straightedge on the fretboard proxy. I think it will be good.


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Bob. Is this what you mean? I have a slight gap. Would that be addressed when I get to the fitting stage and have to floss and fit the neck perfectly?

Best

Carlos

Sorry I jumped in the middle. Yes that’s what I meant and looks like you’re close. You could make a small adjustment to the angle and retry or floss that in later.

- Brad


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You’re really close. You may have jiggled your measuring device, or there’s some movement in your miter gauge. If it were me, I’d work with the scrap wood until I figured out where that small error came from. When you build them in, small errors tend to compound into larger ones. They rarely cancel each other out.

Where’s the bridge? You’re trying to get the string plane at the right height above the bridge. The doming of the top between the heel and the soundhole may interfere with the fingerboard tongue. If that’s the case, you may have to taper the fingerboard in that section to maintain the correct string plane.

Thank you both. Brad and Bob, I got you guys confused for a second there

I left the shop so I don’t have the guitars in front of me at the moment. I’ll have to check where I’m at with the bridge tomorrow. When I put the straightedge on top of the dummy fingerboard with the scrap mahogany with the neck angle cut into it………should the straight edge touch the bridge or should there be a gap at that location?

Straight edge should just kiss the top of the bridge. Some people like a bit of a gap to allow for sting tension pulling up the top.

I advise spending the time now to get the angle dead on, as it’s a lot easier and faster to address that at this stage than it is once the neck is built.