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another bracing critique - my first guitar
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Author:  Heath Blair [ Mon Jun 09, 2008 6:53 pm ]
Post subject:  another bracing critique - my first guitar
well, i thought i would throw this out there for some critcism/advice to see where i stand. this is my first experience at bracing/voicing a top. top is carpathian spruce thicknessed to .105" and all bracing is .250", except the upper tranverse brace, which is .300" (yes, i forgot to drill the access hole. i will have to carefully do that later). not having much experience flexing plates of this thickness, its hard to say exactly what stiff is, but to my hands the top felt quite stiff prior to bracing. at least as stiff as the peruvian walnut back was at .090" and definitely stiffer than a piece of sitka i have.

x brace height is .610" and .700" with cap. peaks on scallops are just under .500" and valleys are around .250". im not sure if this is relevant or not, but i weighed the entire braced top and it weighed in at around 250g. thats with about a quarter inch overhang all the way around. this was on a cheap kitchen scale, so im not sure how accurate it is. to my ears, the top rings nicely with good sustain. anyways, let me know what you think please. all comments welcome.
Author:  LanceK [ Mon Jun 09, 2008 7:16 pm ]
Post subject:  Re: another bracing critique - my first guitar
It Looks great! obviously we can only go by sight and not feel or sound, but it doesn't look "over braced" to me and
that is a common mistake for early builds. If I were to guess, id say this guitar is going to sound very good.

In the truss rod hole, you could always do the access from the headstock end and not mess with drilling in that brace.
if you DO drill it out, try to start with a very small bit, maybe 1/8th and get bigger with additional passes.
If you can, start your bit on the front side, or sound hole side, as your likely to tare out the wood on the exit side of the bit...

Nice Job! [:Y:]
Author:  Rvsgtr [ Mon Jun 09, 2008 7:19 pm ]
Post subject:  Re: another bracing critique - my first guitar
Not too bad. I would scallop down the finger braces a little more from the middles and the bridgeplate is quite a bit bigger than mine but overall I'll bet it will sound good.

As for the t rod access hole. I quit drilling them several years ago due to a strict traditionalist wanting it to look like a vintage Martin with no hole there. I was a bit worried but found it quite easy to feel my way into the nut with the allen wrench. I usually put a little forward slope in the slot in the headblock to allow the wrench to come in from an angle. Ball end wrenches work great for this. And the hole will compromise the strength of the brace somewhat. I try to keep the UTB no more than 9/16" tall at the middle just for this reason.

Great, clean work by the way.

SR
Author:  Hesh [ Mon Jun 09, 2008 7:22 pm ]
Post subject:  Re: another bracing critique - my first guitar
Heath my friend your top looks great! [:Y:] [clap] [clap] [clap] [clap]

Your carving is very neat and as clean as a top should ever be.

Some things that I would suggest for you to ponder:

1) Carp tends to be stiff IMHO so without even testing the top myself, and considering that this is an OM shape, .105 sounds like a good number to me. It also sounds like a great number for a first guitar since we all tend to over build early guitars.

2) The sound hole supports are higher then I would use and could be 1/8" if you wanted but this is no biggie. Some see the function as a stiffener like Lowden with his double thickness here, others see these supports as having the opportunity to be shaped like and function like tone bars and finger braces. Either approach offers stiffening which is all I am looking for.

3) On my OMs I make my X-brace intersection 1/2" or less and cap with 1/16" - 1/32" and this helps the top ring even at the intersection. Tim McKnight helped me with this and I heard much better results at once when I took his very welcome and expert advice.

4) When I forgot to drill the truss rod hole I used a pin vice with as large a drill bit as I could fit in it, perhaps something like 1/16", and drilled a pilot hole manually. Then with progressively larger bits and just my fingers I increased the hole size and it worked fine. The real point here is that we all forget to drill this hole at some point so welcome to the club.... :D

5) The upper transverse brace could be reduced in height toward the ends of the brace in a gradual fashion.

Good job on weighing your top if only for your own future reference. I do this too and as soon as you develop a bit of a data base for yourself some things will start to occur to you.

Nice job - I am sure this will make a great sounding guitar that you will be very proud of.
Author:  Heath Blair [ Mon Jun 09, 2008 11:47 pm ]
Post subject:  Re: another bracing critique - my first guitar
thanks so much for taking the time to comment!

looking at it now, i may actually be able to access the truss rod through the neck block extension without cutting a hole in the utb. ill lay the top on the box and check it out before i make any decisions. otherwise, i think i will drill away using the advice stated.

as suggested, i think i will go to work a little more on the finger braces. i was trying to trim them down some and listen for some change, but i was having a hard time hearing anything definitive. as to the size of the bridgeplate, i hope its not too large. ill have to check the dimensions, i cant recall just now. maybe it looks large because i used a forward shifted/splayed x brace, which would leave a larger area for the plate to span. thanks for the advice SR.

hesh, pondering is what i do best! i actually read that you used a 1/2" tall x and thought about, then decided to go a bit taller to err on the side of safety. do you think i should rework it? it wouldnt be that big of a deal. or should i just go with what i have?

thanks guys.
Author:  Tom Morici [ Tue Jun 10, 2008 12:17 am ]
Post subject:  Re: another bracing critique - my first guitar
For a first, your top looks great!

To reduce chip out, clamp a scrap of wood to the soundhole
side of your transverse brace before attempting to drill the hole for the trussrod adj. Use a brad point drill bit if you have one.

I hope this helps.
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