BYO radius for braces?

bluemoves

Thanks everyone for the interesting and helpful replies on my recent posts <3

A quick one this time:

What is the curve radius for the braces on the back? (and the front too, if you know)

We haven't been able to source a plan for the petite bouche so are just going on internet searches and guesswork..

My dad's about to start on the back and we can't find anyewhere that says what radius the braces should be. Hey buddy, can ya spare a radius (or two)?

Thanks.

Happy Christmas to you all.

(Keep calm and carry on)

ChrisMartin

The Michael Collins book says 12 ft for the back braces.

At the 'front' if you are planning to use a flat top then no radius is needed but if you want to construct it with a pliage then you do need detailed drawings with all dimensions as you will have to construct some sort of former to bend the soundboard in which case your best bet is the Michael Collins book available from this site.

ChrisMartin

Ahhh, I just checked, the Collins book is 'out of stock', maybe you can find a used copy elsewhere? Does anyone know if the plans (which ARE available) have all of the relevant dimensions he asks for?

Buco

Did you check this out?

https://djangobooks.com/forum/discussion/6010/byo-the-pliage/p1

Bones

The short answer for the top is...depends. Just like neck angle, bridge height, action, etc. You gotta do the math. Every guitar is different depending on scale length, number of frets clear of the body, etc. Yeah check out that link Buco posted. There also was a thread that talked a lot about the little tapered shim under the fingerboard extension between the fingerboard and the top. That's the one that really gets into the math.

BYO: Neck Angle, Bridge Height, FC Plan - Page 3 — DjangoBooks Forum

BTW, I modified my top brace arch dimensions to hopefully get rid of the need for the tapered shim but I have not had time to get out in the shop and try it.

bluemoves

we're trying to do a straight up 503 replica.

does anyone know what those radii are?

(incidentally, have studied the well-known '503 - a closer look' YouTube video [freeze-frame / zoom etc.] and can't for the life of me detect the presence of any kind of 'pliage'.. ??)

Buco

Look at the hump right by the bridge, it's at 4:05

Bones

Here's another thread about top braces

BYO Top Braces — DjangoBooks Forum

If you use the Search box and type in BYO you will find a bunch of build info.

No clue what 503 geometry is. In the end, once you pick scale length, neck angle, bridge height, etc. all that geometry is just that, math, I would think.

BTW since I'm a moderator I took the liberty of using my infinite power to add BYO to your title. :-)

Makes it easy for builders to search for relevant posts.

bluemoves

Thanks Bones - so am I right in concluding that once the top is bent down to meet the sides, the 'pliage' sort of ends up as more of a (almost undetectable) shallow and rounded curve, as opposed to a 'peak' with a visible (relatively sharp) centre line'??

Forgive me, I've never seen a gypsy guitar 'in person'..!!

Another question about braces.. are they supposed to extend so that they 'sit' on top of the kerfing? (i.e. the ends sandwiched between the underside of the top and the top of the kerfing) - or, as I've seen in one video, are you supposed to cut small notches in the sides of the guitar so the ends of the braces rest in these slots? (in the video the slots ended up hidden following the edge-binding procedure..)??

Buco

I'm not a builder but I've seen guitars with pliage looking like a sheet of paper that's been creased and ones that look like they have a beer belly. It depends on the technique used and both looks can be the result of a pliage. Then you have a forced top that's also very common and some builders prefer it. It's easier way to go about it and certainly can result with a great sounding instrument.

As far as I know the way Selmer factory did pliage isn't precisely documented.

Bones

Blue, are you planning on bending an actual pliage (fold) or are you just doing a domed (rounded or arched) top?

The pliage is pretty noticable, it is not a sharp corner but a very small (about an inch or so??) radius depending on how small of a diameter pipe you bend it over.

Typically it is plainly visible from the side, or for a finished instrument with a gloss finish you can see a shadow in the correct light and angle. The shadow will show up just behind the bridge. Probably the reason you don't see it on 503 is the finish is so dull from age and scratches that it doesn't reflect the light very well. I'm not an expert and I have never held an actual Selmer but I think all the originals had a fold (pliage)???

I'll try to post a picture later.