Neck Block is Not Flush With Sides

[phavriluk]

No harm in calling Martin and seeing if they will send you another neck block. Calls are cheap. I think this ain't the time or place to try to set the neck block in place and fill the gaps with anything. Shouldn't be any gaps, I think.

This question is best handled by someone who can bring some skilled and experienced insight to the problem.

[phavriluk]

There's a couple of books that would get OP a long way in building his instrument, maybe standing down on the project till they get read and absorbed....these are Bill Cory's 2 books on assembling kit guitars in general and Martin kit guitars in particular. At least in the books the skilled advice is coming from one source. Often times we well-intended bystanders don't give answers that play well together.

Bill's books are available online and his square advertisement block is to the left of these postings.

[tippie53]

The block is not defective you have to sand these parts together. Here is a link that may help.
Also can you post a picture. If the neck block is bad it can be replaced . Where did you get the kit? If you got it from Me or Martin we usually check the parts that they are ok. If you got it from Ebay you may have to get another. The Neck block does have a radius to it to match the mold , the are not flat across the neck. If there is a radius on the corner of the block on the joint side that is not good.
We are here to help
https://www.youtube.com/watch?v=LrgRKKsxL-M

[tippie53]

post a pic we can help for sure

[johnnparchem]

Using a straight edge does the side facing side of the heel block have a curve top to back? I would want the block to be flat top to back. Having a gap before clamping would not be surprising to me. Lots of possible reasons. The sides make bad straight edges. I sand in a slight curve side to side.

[tippie53]

that is fine actually
the block has a radius at the dovetail and it has been there since the dovetail block was made. The over hang is needed so you can adjust the neck angle. You want about 1/8 out the back and about 3/32 at the top. check out the link
https://www.youtube.com/watch?v=FcM3GErOI_A
you want to build in about a 1 1/2 degree angle in the sides so the top will have the geometry you need .