Martin Bolt-OnNeck Problem

[klooker]

I've been working on a Martin kit with bolt-on neck.

Everything has been going fine until now.

I attached the neck to check initial fit & alignment. When I tried to raise it up until it was level with the top, I discovered that it won't raise up enough. It's about 1/16" or 3/32" too low.

Any ideas?

Kevin Looker

[tippie53]

you can work the hole for the screw so you can set the neck up where it belongs.

[klooker]

Thanks for the reply John.

Lengthening the hole for the threaded part of the screw can be done from the outside. Enlarging the countersunk area for the screw head is a different matter. I realize that I could lengthen the slot, get a longer screw & put a big washer under it but this seems pretty rough.

I think it's odd that the neck & block don't match up since everything in CNC cut. Is it possible that maybe the block goes to a different style of neck like a stratabond?

Thanks,
Kevin Looker

[klooker]

Here are some more photos.

I put a combination on the top surface of the neck and ran the blade down until it touched the top of the threads on the screw. It measured about 2-1/4".

I then put the square on the top of the guitar to see where the top of the screw needs to be for the neck top to be in line with the guitar top. The hole is definitely too low.

Kevin Looker

[kencierp]

Pictures worth a 1000 words --- just a spade bit with a cutting edge ground on the shaft side. You pull the drill outward:

[klooker]

Thank you Ken!

That's my neck block & that should work.

Does anyone know what's up with these OEM Martin neck blocks? I'd think such a modification would not be needed.

Kevin Looker

[Guitar Hack]

This is a little off topic but any problem with just cutting the top part of this neck block off? Makes it hard to get an allen wrench in to make adjustments unless you got a really long one.

[klooker]

The kits sold by Martin have the standard X-bracing which is designed to work with the dovetail neck.

The mortise & tenon (bolt-on) necks are designed to work with A-frame X & modified X-bracing.

If you order a kit from Martin with bolt on neck, you will have to trim some of the head block to make clearance for the graft on the underside of the top but this will also make it easier to access the truss rod. The block shown in Ken's post is the Martin bolt-on type for A-frame & modified X-bracing.

Kevin Looker

[klooker]

I went ahead & lengthened the slot & increased the size of the countersink on the inside. Thanks again to Ken for spade bit idea.

I realize that this has no bearing on getting this kit built, but does anyone have any idea what's up with the bolt-on neck & block that Martin supplied?

I loosened the bolt & pushed the neck down as far as it would go. If you look at the photo, you'll see what it looks like. In it's lowest position, the top of the neck is 1/8" below the top of the block & almost 1/4" below the top of the guitar. They designed it this way on purpose?

Enough ranting.

Thanks for the help.
Kevin Looker

[Ken Hundley]

You are expected to remove some material from the top of the neck block when you sand your rim,and Martin has no idea where, depending on your body depth and how you sand your rim, where the neck will fall flush with the top. This gives you plenty of room to work with.