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Upper bout radius - or flat?
Posted: Sun Feb 15, 2015 9:02 pm
by Dave Bagwill
I cannot find the thread where this was discussed, so could I ask for a reminder?
Your best practice as to:
1. x-braces - radius the upper bout or leave flat
2. UTB - same question
3. bridge plate - glue it on flat or in a 40' dish?
Re: Upper bout radius - or flat?
Posted: Sun Feb 15, 2015 11:39 pm
by John Parchem
I would not describe my process as a best practice but I
glue the bridge plate down how ever it is convenient, that is I do not care if I glue it flat or in the dish.
I radius the entire x-brace
I radius the UTB then plane the center area that will be under the fret board plus a bit flat with. I glue the UTB against a caul that is radiused and flattened in the center (basically matching what I did to the brace. )
I use a 32' radius for most of my tops. If I was using a 40' I would just radius the UTB and glue it down.
You need to be careful with my practices as I have them tuned to give me a top angle that matches my target neck angle using a specific radius dish. Ken describes a more fail-safe way to get the top angle to match the neck angle.
Re: Upper bout radius - or flat?
Posted: Sun Feb 15, 2015 11:57 pm
by Kevin in California
I've been gluing that transverse brace in flat like John about 4in across the center. I found there is a much flatter top here for the fretboard extension to lay on. The tonge depressor brace helps in this way too. I also radius the entire x brace surface. This has all worked well for me on a number of dreds and one OM.
Re: Upper bout radius - or flat?
Posted: Mon Feb 16, 2015 12:24 am
by Dave Bagwill
So - you both do like to get a little dome in the upper bout? I suppose what got me thinking about this was remembering the Godin factory tour, where the guide was mentioning that they have a flat upper bout and a dome on the lower bout.
Re: Upper bout radius - or flat?
Posted: Mon Feb 16, 2015 1:22 am
by Tim Benware
All my braces above the x brace are flat. I radius the x brace and tone braces.
Re: Upper bout radius - or flat?
Posted: Mon Feb 16, 2015 10:43 am
by Herman
I make all flat except for the lower ends of the X-braces.
2ct
Herman
Re: Upper bout radius - or flat?
Posted: Mon Feb 16, 2015 11:10 am
by ken cierp
I do it like Martin except use 40' instead of 52' contour (an added small margin for possible RH shrinkage)
"X" full
tone bars full
bridge plate flat
Popsicle and finger braces flat
shoulder brace -- just a touch of slope on each end to accommodate the FB extension area 1.3 degree slope around the perimeter
BTW KMG kit builders (Martin and Gibson styles) these brace mods are already done for you -- carry on