Official Luthiers Forum!

Hello.

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

Everything has been going fine until now.

I attached the neck to do a preliminary check & I discovered that I can't raise the neck high enough so that it will be level with the top.

The slot in the block isn't long enough.

Any ideas?

Thanks,
Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

I had the same problem with a Martin neck and neck block that I bought. I ended up extending the cut out portion that you see in your first picture,and extended the side of the slot upwards, it was just enough to clear the head of the screw and allowed it to screw in. Does that make sense?

_________________
Tim

Before you do too much, is the neck angle right to give the string height at the saddle, and if so is the top sanded to match the level of the neck so the fingerboard will lay flat on it when the neck is dropped. This might not be as bad as you think, remember Martin sands the 1.5 degree angle into the sides from the waist forward to match up with the neck angle. Get all the angles right before dropping the neck farther into the block.

Check Hesh's tutorial on fitting bolt on necks.

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Thanks for the replies.

The neck is as high as it will go & the fingerboard can not lay flat on the neck because the top of the body is essentially too high. See photo.

The slot in the head block needs to be lengthened so the neck can get as high as the top.

I'm going to wait to see what Martin has to say about the whole thing. Not to offend the folks at Martin but it seems a little flaky selling a kit with incompatible components especially when everything is CNC cut.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Kevin,

Just a thought, but, how thick is your top? It may be the pictures but it looks really thick, it might be thinned to help with the match up.

Cecil

To me from the photo the fingerboard if parallel with the neck will not be parallel with the top. I also think your top is a little thick looking. As I stated above have you angled the top to match the neck angle, that should put the neck in position or at least closer. At Martin they use the same parts to build hundreds of guitars per day so they should fit if everything is done right. I am not trying to be critical but check your work and the neck and top angles.

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Martin (or any kit supplier for that matter) uses an average to determine what the thickness of your top might be...and even that won't take into consideration what happens when you radius the sides (and consequently the top of your neck block) prior to closing the box. In other words, it won't likely be a perfect fit anyway - and your photos indicated you really aren't very far off. This is one of the few negatives with building a kit...the neck fit. But it's an easy fix.

I've known many people who have had to rearrange their block holes to take advantage of the threaded insert already placed in the neck. If you do (and I agree with Fred that you need to carefully look at the angles first), just use a dowel rod/s to fill in the neck block hole/s, fit the neck, mark the block where the threaded insert falls, and redrill your holes. Viola', your neck is ready for flossing, etc.

The reverse of this procedure, is to pull the threaded insert from the neck, fill, mark and redrill. That's probably as easy as doing to the neck block come to think of it. It's up to you.

Hope that helps.

_________________
Eagles may soar, but weasels don't get sucked into jet engines.

Thanks again for the replies & please don't worry about being critical of my work. I appreciate all input & suggestions.

I measured the top thickness & came up with about 0.120" (3 mm). That's how the top came from Martin. Is that unusually thick?

The attached photo shows that the neck angle needs some adjustment. Correcting the neck angle will help the bolt clearance issue but I still don't think it will be enough. The distance from the top of the neck to the top of the bolt is 2-1/4" and the distance from the top of the body to the top of the bolt slot is about 2-5/16". I think that the block is designed to be used with a thinner top or a different neck. Who knows but I think I'll be working on lengthening the hole tonight.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

You don't need to fill anything or move the insert or anything like has been said. As I originally posted, the elongated part of the hole, on the outside of the neck block, that the bolt fits through, just needs to be lengthened toward the top a small amount. It is no big deal and is a very simple procedure. Just use a small round file or rasp and go slow taking off a little and rechecking it until correct. Then the round part of the recessed hole on the inside will need to have the same thing done to it so that the bold head clears it. I did the same thing on mine and after that everything lines up fine.

Don't try to make this more of a job than it has to be.

_________________
Tim

By the look of the space between the straight edge and the top you need to get the neck set before worrying about the bolt hole. If you have not yet read Hesh's tutorial on bolt on neck setting read it before going forward http://www.lenaweelutherie.info/page6/page31/page31.html

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I went ahead & elongated the slot. It was not a big deal but I'm not convinced that this neck/block combo are ideal.

Getting the neck angle correct may have allowed the bolt to pass through but it would still be up against the top of the factory slot.

If I loosen the screw & push the neck down to the bottom of it's adjustment range, to neck is about 1/8" below the top of the block which corresponds to 1/8" below the bottom of the sound board. - see photo

The other issue is that when it's "done" there will be almost 1/8" gap between the top of the back binding & the heel cap. - see photo

I'll get off the soap box now.

Thanks,
Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Update:

Martin just emailed me & said that the heels on the bolt on necks are shorter & typically won't reach the binding.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Kevin, you could make the cap thicker, either the same material or go for the layered look.

_________________
Aoibeann

Is it a dovetail or a straight mortise and tenon?

If it is a dovetail can't you glue a venner to each side of the dovetail, this would not alow the neck to slide
all the way into the female dovetail mortise. Then just sandoff little by little from the male dovetail cheeks till the
neck flushes out at the top.

if it is a straight mortise glue a shim to the bottom of the mortise or tennon and adjust tillit is flush with the top.

Personally, I would extend the slot in the neck block... The top of the neck does need to match up with the top of the body... It's easy enough to extend that slot with a dremel.... The challenge will be counter-boring the inside to look right through the soundhole....

Then, decide whether the heel not matching up to the back aggravates you or leaves a visible slot.. If it doesn't - put on your normal flavor heel cap and call 'er good... If it bothers you or leaves a visible slot - glue up a stack of veneer pieces and a piece of cutoff from the back or headplate veneer to make it level at the right height.

As you are running into now - this is the sort of thing that is *Much* easier to work out when you are dry fitting things on the bench.... You would really like to know that the slot isn't long enough *before* the top is glued to the neck block...

Thanks

You have a few design options . I used to use a few pieces of contrasting woods and make the heel longer . Looking at the neck you are fine and lowering the mortise will serve no purpose . As for getting the proper neck angle you will do have room there and even though this is a dove tail video , the principals are the same . Neck angle , center and drop to top . http://www.youtube.com/results?search_q ... etail&aq=f
If you make a series a marks for reference along the heel , you can remove the stock so you can get the neck angle correct . You want to see about 1/16 to 1/8 off the top at the saddle position using the neck plane . With a fretboard on and frets I like to see the line just of the bridge a tad ( about 1/32 to 1/16 )
When you are done you like to see 1/2 inch string height in front of the bridge . Happy New Year and enjoy the experience

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I keep forgetting to check the "Notify me..." checkbox when I post on this forum.

Anyhow, the guitar's done.

I made a modified spade bit as suggested by Kencierp from the Kit Guitar forum (see picture). I used the bit to enlarge the countersink inside the guitar then I lengthened the slot with a file.

For the heel I glued on a piece of rosewood to lengthen it.

I think Martin must sand a lot off the top edge of the rim & block before gluing the tops to these mortise & tenon neck guitars.

Thanks for all the help,
Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.