RE: back doming question from a beginner

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Jeff Highland

Posts: 401
Joined: Mar. 5 2010
From: Caves Beach Australia

RE: back doming question from a beginner (in reply to wfrancis86)

Just assembled this with a 10ft radius back and 6 degree bent top with ladder bracing varying up to 7ft radius
I used Estebanana's flrxible lath concept on the front braces, but inverted it and used it on the go bar deck
Fitting the linings for the front was interesting....

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REPORT THIS POST AS INAPPROPRIATE | Date Oct. 14 2012 3:05:54

Tom Blackshear

Posts: 2304
Joined: Apr. 15 2008

RE: back doming question from a beginner (in reply to jshelton5040)

quote:

ORIGINAL: jshelton5040

quote:

ORIGINAL: SEden

I'm not sure where you are coming from when you say ripple. My thoughts on this is, perhaps your dish is small and tends to cut more on the sides and less on the end blocks and heal blocks? I guess that can cause a ripple.

I understand now. We use a traditional taper rather than using the radiused dish to shape the sides, foot, etc. If we glue all the braces on using the radiused dish the braces don't conform to the desired arch from end to end making ripples in the back (caused by one brace being a little too high or low). It only takes a few minutes extra the way we do it and I like the looks. I'm sure I'd like the looks of yours as well it's just hard to change after doing it a certain way for so long.

Hello jshelton, I put my guitar backs on free hand, which means that I can adjust to any radius for sides and length.

First I will use the side depth as 1/8" difference from bottom to top. Let's say 3-7/8'' at the bottom and 3-3/4 at the top by the heel with the difference split at the waist. Then I measure with a straight edge with its side edge placed on top of the heel to the bottom end block which should raise the straight edge to about 1/2" high over the bottom block.

Then I fit the back braces to the mearsurement by starting at the heel first. Using a straight edge, going across to the sides, the heel itself should not provide more than about a 1/16" clearance over the sides at the upper bout.

Then I measure the middle brace about 1/32" higher, in its middle, than the brace at the heel, following the basic taper, then the third brace at the lower bout is dropped about 1/32" from the middle brace, and you should have a near perfect back dome with very little adjustment on the sides, if any, to make it fit perfectly.

This will give you a gentle horizon from top to bottom and side to side. And this can be changed by hand to any measurement you wish, just by following the taper at the heel to the bottom block, and side to side clearance. You can raise or lower the dome at will.

_____________________________

Tom Blackshear Guitar maker

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2012 12:33:46