Top on the sides - fore / aft position?

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Omar_8200
Posts: 11
Joined: Sun Oct 09, 2011 7:07 pm

Top on the sides - fore / aft position?

Post by Omar_8200 »

I am building a Martin D kit. Body length is 20". Don't have a plan. I have to sides assembled, top braces, and back braced. My next steps is to shape braces and inlet the X braces into the sides for the top.

The top clearly needs to be centered laterally on the sides. I match the center line of the top with the center line of the tail and heel blocks. This works fine.

How do you position the top fore / aft on the sides? I measured the top and it is 20 5/16" in length. I have 5/16" to play with, but it seems like the top of the sound hole should be a specific distance from the heel block.

Checking through the Martin book that came with my kit and also Bill Cory's Martin kit book they indicate that I should place some dowels through the holes in the top. Makes sense, but there are no holes in my heel block to match up the top with!

Any help you can provide is appreciated.

Thank you.
Omar
- Mandolins and guitars constructed in the foothills of the Rocky Mountains
Jim_H
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Joined: Tue Sep 06, 2011 2:51 pm
Location: Bothell, WA USA

Re: Top on the sides - fore / aft position?

Post by Jim_H »

I can't answer your question specifically because I don't have the Martin D specs, but the critical factor is to locate the bridge location in order to maintain your scale length integrity. You have a small amount of leeway here, but your bridge needs to be properly located over your bridge patch, and so you'll need to locate the top in the proper location to ensure your scale length is correct.
My poorly maintained "Blog"
kencierp

Re: Top on the sides - fore / aft position?

Post by kencierp »

The neck edge center line of the sound hole (assuming it is 4" in diameter) is 3 7/8" from the outer perimeter at the neck block. Of course Jim is correct -- setting the bride/saddle in the proper location is critical when that time comes.
naccoachbob
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Location: Nacogdoches, Tx

Re: Top on the sides - fore / aft position?

Post by naccoachbob »

I think I saw where John Hall said the soundhole is about 4" from the neck joint.
On my Stew-Mac plans it is exactly 4". My plans are for a Martin-style Dreadnought.
Best of luck,
Bob
tippie53
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Re: Top on the sides - fore / aft position?

Post by tippie53 »

Doweling the neck block is easy to do before you glue in any bracing. Tape the top on the sides with masking tape centering the top . I use the mold for the center lines and locate the neck line on a 14 fret 4 inch to the top of the sound hole. 1 in from the edge and 3/4 in from the center lines you can place 2 holes. I use 1/4 in.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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