When do YOU cut your neck block mortise?

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James Meloan
Posts: 13
Joined: Thu Jan 12, 2017 2:35 pm

When do YOU cut your neck block mortise?

Post by James Meloan »

On my steel string guitars so far I've done a simple 2 bolt mortise and tenon neck joint, and have always cut the mortise in the block before gluing it in. Had no problems. But I hear the sweet song of the great dovetail cult a' calling and I can't resist any longer.
I can't think of a reason not to cut the DT mortise in the neck block before glue up, aside from possibly gluing it off center, but that's preventable. Am I missing something? Does LMI sell that double sided neck joint jig for a good reason (other than being able to easily dial in your neck angle)? Should I really try to rout the mortise after the box is together? That seems way more risky than gluing the block off center.
Brian Evans
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Location: Tatamagouche, Nova Scotia

Re: When do YOU cut your neck block mortise?

Post by Brian Evans »

The main thing, in my rookie opinion, is to do the thing that gets the best, most repeatable result with the least amount of work. To design a process that can be repeated time after time and puts the mortise in the right place, angle and depth. I just built a jig to cut the neck mortise, and I was using a completed body, so that's the jig I built. What I found was it made it easier to place the mortise exactly centered on the body, square to the center-line of the body (which was not the same as square to the plane of the sides of the body at the neck block, this body wasn't quite squared up at that point), and adjust to the depth I wanted taking all of that into account. The other thing is you need to have your body mortise match your neck tenon. What I did is build a jig to cut the neck tenon first, which set the neck angle, and then I matched the mortise to the tenon.

I can see issues cutting the neck block before assembly. I guess what I think is that by making that part easier, all subsequent steps will be harder. Anyway, after you build your jigs the hard part is done, you just set up your router, run a few test pieces and the cuts take about a minute. Love to hear what other people think.
Alan Carruth
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Joined: Sun Jan 15, 2012 1:11 pm

Re: When do YOU cut your neck block mortise?

Post by Alan Carruth »

One of my normal rules is 'never cut anything until you need to '. Cutting the mortise before you glue the sides up risks getting it off center, or any number of other little issues. Cutting it when the box is al together allows you to get it in the right place more reliably.
Todd Stock
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Joined: Tue Feb 28, 2012 7:57 pm

Re: When do YOU cut your neck block mortise?

Post by Todd Stock »

After the box is closed and bound.
Kevin Looker
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Joined: Tue Aug 21, 2012 1:36 pm

Re: When do YOU cut your neck block mortise?

Post by Kevin Looker »

I've always done it prior because I haven't invested the time and/or money in a jig.

Cutting afterward definitely makes sense.

Anyone willing to share their setup? I've looked at the building the O'Brien Jig and I've also looked at the Luthier Tool jigs which look very nice but $$$.
James Meloan
Posts: 13
Joined: Thu Jan 12, 2017 2:35 pm

Re: When do YOU cut your neck block mortise?

Post by James Meloan »

Kevin Looker wrote:I've always done it prior because I haven't invested the time and/or money in a jig.

Cutting afterward definitely makes sense.

Anyone willing to share their setup? I've looked at the building the O'Brien Jig and I've also looked at the Luthier Tool jigs which look very nice but $$$.
I have the LMI templates and 7 deg. dovetail bit, and have the O'Brien jig pretty much built, but I am not crazy about the way that the jig holds the box while you rout the mortise. Maybe just adding a clamp thru the soundhole will make it more stable. I'll fuss around with it some more.
Todd Stock
Posts: 394
Joined: Tue Feb 28, 2012 7:57 pm

Re: When do YOU cut your neck block mortise?

Post by Todd Stock »

I have room in the shop for separate mortise and tenon jigs, and the concept of combining the mortise and tenon cutting function never seemed like a good idea to me, given the compromises in holding an alignment needed for in a single jig or fixture. A shop-made Woolson neck jig (which is where the LMII and Luthier Tool jig come from) gets used for the tenon or dovetail, and the mortise or socket gets milled with my own jig.

The operating part of the jig is a simple reinforced 90 degree joint with the template (which slides to define length of the mortise/socket) in the horizontal plate (as shown), and cork-lined cauls and cork blocks securing the body. A centerline stuck on the vertical plate and an end-graduated ruler for mortise or socket location gets the joint in the right place. A D-handle DeWalt router (the Milwaukee shown is now in the router table) with a top=guiding pattern bit installed does the deed.

Remember to use a sacrificial backer between neck and vertical plate on the Woolson jig to preserved the sharp corners of the neck cheeks (blow-out happens if not backed).
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