Martin Jumbo - Rosewood Kit

[MaineGeezer]

Not a problem. Add shims. Standard procedure.

[Selah]

What do you recommend the shims be made of? I will need almost a 1/4” of shims. 1/8” on both sides.

Would popsicle sticks work?

[MaineGeezer]

How did it get to be so far off? Did the parts come that way?

Shims can be just about any wood that glues well. Popsicle sticks may be a bit narrow, but otherwise they would be okay. I think I would make the shims closer to the width of the dovetail surface though. (I may be making an inaccurate assumption about relative widths here.)
You will need to keep track of which shim is left and which is right; at least, I always seem to need to., as they end up being different as I adjust the neck neck position. l
Are you sure you need a 1/4" of thickness? The neck may be 1/4" low, but that doesn't translate to 1/4" of shim thickness. Looking at your photo, I'd guess you'll need more like 1/16" total shim thickness. The taper on the dovetail has a big effect. See drawing. Adding a 1/16" shim raises the dovetail contact point by over 0.3".

[Selah]

Yes. It came that way from Martin. I bought three kits, so I checked one of the neck blocks from another kit. The gap in the other neck block at the top of the wedge is 1.55”. The gap in my neck block is 1.77”. See the photos. The difference in the two is where I figure I need about a 1/4” of spacers.

[tippie53]

there are 2 different blocks on is for the 000 and OM the other a dred shims will work fine

[Selah]

Here is the end of the neck on two of the necks. The one on the left has an insert for a bolt. The on on the right does not. They are both for the same Martin Jumbo kits. Are they supposed to be bolt-on?

[MaineGeezer]

No, unless I am totally missing something (which is entirely possible....) you won't need 1/4" of shims or even 0.220" of shims.
To reduce 1.77" to 1.55" you'd need a shim of 0.11" on each side.
But if you add a 0.11" shim on each side, you'll raise the neck by about 9/16" of an inch.
I expect that is way more than you need, judging from your first picture.
(That 9/16" number assumes your dovetail included angle is 22-1/2 degrees. It should be close to that, anyway.)

Go back and look at that picture I drew a couple entries back showing how a 1/16" shim raises the neck by over 5/16".

It looks to me as though that 1.77" pocket is going to be about right, requiring a couple of shims 1/32" thick or a bit less, and the 1.55" pockets are going to be a tad bit narrow if the ends of those necks are the same as the one you show.

But I wouldn't trust my numbers. It is conceivable that I'm missing something. Experiment with some shims and see what you get.

As far as the threaded insert and the hole for a threaded insert...you've got me. It appears as though those necks have a proper dovetail pin cut on the end. No idea.

[tippie53]

that threaded insert is used in the production floor to mount the neck in the finishing process a bolt would not work with the dovetail and in fact is counter active to the way a DT works

[tippie53]

looking at your pictures you got the wrong neck block so you will have to shim it but that won't deter the strength at all your good to go follow Mainegeezers advice your on the right path

[Selah]

Thanks for your help. I think I got a shin of a couple wide popsicles that seem to shim things up right amount.

I glued the top on this evening. Let’s say a prayer that it worked.