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The top I ordered from Martin to study came yesterday, and I have a few questions I was hoping some of you may be able to answer. (I got home too late to call Martin today).

I'm trying to determine the scale length in order to understand how they're positioning the bridgeplate and everything else. If I measure from the top, it seems to work with 25.4" and if I measure from the bottom, it works with 24.9". Does anyone know where I should be referencing from? Knowing how far the top of the soundhole should be from the top of the soundboard would be a big help? Also, do I reference the braces from the top of the rectangles or the bottom?

The top, by the way, is 20" long, making it 3/4" longer than their OM. That's what's creating the confusion. I don't know where to reference.

James,

That extra 3/4" is trimmed off after gluing to the rims.

I'd reference off the neck junction, or what I'm guessing you're referring to as the top. Don't pay attention to the soundhole location, it just falls where it may in relation to the end of the fretboard.

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now known around here as Pat Foster
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James, those two closely-spaced holes are for indexing the top to the neck block (and thus, the assembled rim) in a Martin factory jig for assembling same. It might be, the way Martin designs this operation, that there will be overhang of the plate on both ends and sides of the rim/body after assembly, so I am not sure you can reliably measure from any of the edges of this top plate.   

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"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

That's what I was suspecting too, Steve. Well, I guess I'll wait until e
Monday to give them a call

The OM is 25.4 and the 000 is 24.9 with the same body.

Hi James:

The center of the 0.250" holes above the sound hole finish out to be 1.000" from the 14th fret neck joint. They should be 1.125" from the center of the holes before trimming leaving 0.125" to be trimmed off. The overhang at the end block is much more.

As for the bracing...Connect the top edges (nearest the sound hole) of what they've drawn for x-brace locations. Measure from the lower edge of the soundhole (nearest x-braces, bridge, etc)to the intersection of the x-brace lines you just drew. The distance should measure 1.25" between the soundhole edge and x-brace line. If it measures this, then the line you drew corrseponds to the top edge of your x-brace. When you glue, just line the edge of the braces up with the line and you'll be fine.

If you have an ibex fret scale, draw a line 0.125" from the edge near the 0.250" holes and use the fret scale, lined up with the 14th fret marker at the line. and determine the sadddle location. This will give you a good idea of where the bridge will fall.

A quick way to determine the scale length is to take a fret board and line the 14th fret up with the line above the 0.250" holes and see how it lies. If the edge of the fretboard (25.4") comes close to the top edge of the sound hole, it's most likely a 25.4" top. The other scale would be 24.9" so you'd know the difference.

Also, the top edge of the soundhole should measure 4.125" from the edge of your top at the neck joint before trimming or 4.000" after for a 25.4" scale.

OK.. Enough Rambling.

Hope that helps. If not feel fre to call, PM, etc.

Let us know how it works out!

Don Sharp

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Don Sharp
Got Brazilian?
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Don, you are right on! Thank you!   There was a very small cut on
the top that ended right where that top line is, so I suspected it was there
but wasn't sure because it's a reject top and wondered if someone may
have made an incorrect cut.

The only thing that seems different is that the top of the X-brace joint is
1.325" below the bottom of the soundhole (soundhole is 3.8").

Do you know how far below the soundhole that joint is for the pre-war/
advanced bracing and how far it is for their regular bracing?

HI James:

The "forward shifted" bracing falls 1" below the sound hole.

Don

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Don Sharp
Got Brazilian?
http://www.sharpguitars.com