Page 1 of 1

soundhole patch

Posted: Mon Nov 26, 2012 12:42 am
by Andrew Jerman
I am building my first guitar. On ukuleles, I have used a sound hole patch but I've seen braces and sound hole patches on various sets of drawings. I am not working from a formal set of plans. Can anyone offer a reason to go one way or another?

Thanks

Re: soundhole patch

Posted: Mon Nov 26, 2012 1:19 pm
by Chuck Tweedy
Steel string or classical/flamenco ??

Re: soundhole patch

Posted: Mon Nov 26, 2012 2:21 pm
by Andrew Jerman
Steel string with a Venetian style cutaway.

Re: soundhole patch

Posted: Mon Nov 26, 2012 2:58 pm
by Chuck Tweedy
On a steel-string the general scheme is to surround the hole with braces.
- The X upper arms cross below the hole
- The "upper transverse brace" goes across the top of the hole
- 2 more braces flank the hole and go from the X upper arms to (or under) the upper transverse.

Me, and many here, and many factories now, use an "A-frame" structure in the upper bout with the 2 braces that flank the hole (last in my list above).
In this structure, these 2 (1/4" by 1/4") braces butt up against the X arms, pass under the upper transverse brace, then butt up against the heel-block. It forms a nice structure that both helps the soundhole from collapsing, and helps keep the top from cracking on either side of the FB.

I could post a picture later if that would help - don't have one here.

Re: soundhole patch

Posted: Tue Nov 27, 2012 4:56 pm
by Alan Carruth
I've been using an A-brace for a long time: I think even before Martin took out the patent! Lately I've been adding a patch as well. I tend to use a fairly wide rosette, and the patch helps reinforce the thinned area of the top.

Alan Carruth / Luthier

Re: soundhole patch

Posted: Tue Nov 27, 2012 5:45 pm
by Chuck Tweedy
Interesting - didn't know that was patented. Thanks for the heads-up Alan.
1995, by Michael Dresdner. That guy is everywhere!

Re: soundhole patch

Posted: Wed Nov 28, 2012 5:09 am
by Jim Ashby
If the patent was filed or pending before Jun 8th 1995 it should be expired by now.

Re: soundhole patch

Posted: Wed Nov 28, 2012 10:43 am
by Steven Smith
I did a soundhole patch on my current project where I have modified Trevor Gore's plans for a falcate-braced top to fit on a dred. I like the the way the patch locks everything together and also backs up the rosette like Alan said. I will probably use it in the future on X-braced tops as well.
FalcateTop.JPG