Official Luthiers Forum!

How do you hold the top and back plates steady when carving braces.
Do you use a special jig?
Do you use some sort of special mat to lay the top/back on?

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Formerly know as Mandodiddle.

I have a little table a bit bigger than the top or back, with 3" legs. It gets the work a bit higher, allows for clamps, and I can drape it over the side of the bench to work at an angle. Old school, no vaccum, nothing fancy. Saw it in an old workbench book; it's what Somogyi was using at the time.

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formerly known around here as burbank
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http://www.patfosterguitars.com

Non slip router mats, one under the radius dish, one in…

I show my setup here:

viewtopic.php?f=10101&t=55545&hilit=Total+vise

I’m very, very happy with it. I use workboards that are dished out for the applicable radius of the braces: 28’ for the top, 15’ for the back. These are mounted to a Total Vise mounting plate, and the mounting plate goes into the Crossover Mini, which goes into a base that is bolted to my workbench through dog holes. Solid as a rock, but capable of being positioned however I want. Not cheap, but if your back bothers you, this is a great way to work.

http://www.kennedyguitars.com/holder-fo ... aping.html

I have holes drilled in the radius dish in proper places to put dowels for stops. I have a guitar shaped cork covered cardboard to put under the top.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Non slip router mat, radius dish in go-bar deck and 2/3 go-bars.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Left hand, palm down on the top (on a piece of carpet). Right hand holding chisel. I use a half inch chisel with a long handle, rounded corners on the tip, and bevel down. It is very sharp, takes light cuts, and doesn’t need much pressure. I turn the carpet as I cut rather than the top so that I’m not marring the top with any cutoff pieces. When I pick up the top to tap, that’s when I dump the shavings from the top and the carpet.

Just what I use, that and some care.

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Peter Havriluk

Radius dish and a couple of cam clamps.

I've learned, through experience, that it's best to avoid holding things with your hand when using a chisel. Basically, the shop rule is that both hands are behind the edge at all times, which means you'll use clamps most of the time, at least. Move the clamps when you need to; you're not in that much of a hurry....

My hand is always behind the chisel point. I learned that long ago (and have a permanent crook in my finger to prove it). That’s why they call them “hand tools.”

I use an adjustable solara, the top is easy. I use a rubberized mat for the back. Hands always behind the tip of the chisel.

Like Alan said a couple of cam clamps in a radius dish - I use my sanding dish with a few layers of newspaper...works perfectly for me...

Pretty much what I do too.

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Steve Smith
"Music is what feelings sound like"

This…

I put my radius dish on top of a 12” dia. lazy Susan and a non-slip mat on top of the dish. The lazy Susan provides clearance for the top to be clamped to the dish.

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Measure Twice,

Karl Borum

Do you find that holding the plate around the entire edge makes a big difference over free plate tuning? I notice when glued up, plates that were tuned free, do need thinning around the edge; and even other places. On a carved instrument that is easy to do. I would be far easier to do on the inside with the bracing on a guitar. It usually isn't even that much material, but it does get more even.

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Why be normal?

Yes, I can hear a change in pitch without having to use an analyzer. Free plate tuning never made sense to me - I couldn't hear any difference after I made a change.

Best,M

I usually graduate plates before gluing on the braces, and then use the Chladni method to 'tune' them. I find that I get better basses when I thin the plate toward the lower block, and better trebles when I thin the 'wings' of the lower bout. Chladni tuning, in my mind, is a method for getting the braces and the plate into some sort of balance, and the evidence of that is in the number and form of the modes. Well-formed modes tend to 'ring' longer when the held top is tapped, and produce a clearer sense of pitch, both of which are signs of low losses. Ultimately you can get much the same information either by tapping and holding, or with Chladni patterns. Tapping and holding takes less time, once you know how to to do it, but it takes more effort to get the same amount of information. I find it's also easier to teach the Chladni method, and easier to save the data.

I clamp pieces of wood to the edge of the bench so I have something to push up against. Best to have two stops, but after you get the rough shaping done it's usually quicker to have one that absorbs most of the cutting force, and left hand to prevent the top from rotating. I also use my left hand to help guide the blade, so it's out of the line of fire. Slipping and cutting the soundboard is the greater danger.

I use an old T-shirt as a pad underneath, and clear away the chips frequently.

I lay the top on folded beach towels so I don't dent it up. I haven't had trouble with it shifting around so much as junk getting under it and leaving boo-boo's.

I shake the towels out regularly, and wash when needed.

The plate (top or back) sits on a router pad inside a radius dish. I find it secure enough and CHEAP, I get to use my radius dishes for more than gluing braces.

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Peter Havriluk