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Any tips for carving my first top and back for an A-style mando?

Get yee a 2x10 and practice...

That's actually what I'm doing...I've got a 2x8 of some old old pine of
some sort that's about 1/2 way quartered. It's laying around, doesn't cost
me anything, and if I get lucky and get a good top and back out of it, I by
darn plan on using them!

Okee, jolly good show, then.

carve the exterior first, get it all nice and just the way you want it, right down to fine sanding, then carve the interior. Don't use templates. Use your eye. Use light to your advantage to view the arch as it progresses.

Once you've successfully carved two plates from your junker wood, dive into the good stuff. I usually advocate using good wood right off the bat, but carving is something that needs to be learned, and the eye doesn't always 'get' the curves right until it's been done a couple times.Mario38844.4655208333

Don MaCrostie has a great video on the topic. available from stew mac.

_________________
Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

I would also recommend the Roger Siminoff book "The ultimate bluegrass construction manual". He offers a few ideas on plate carving. Some of the best advice I have gotten is that you carve the recurve until it glows when light hits it from the backside. The precise details are a little more complicated, but it should be slightly luminescent in the recurve.

until it glows when light hits it from the backside

Careful! Not all woods allow light through like spruce does. The firs, and cedars don't. Neither does maple. Even with the spruces, the denser spruce won't show light until nearly too thin...

Its a great method for refining the recurve and getting it very even, but measure first, them check with the light....

Mario -

Out of curiosity, why do you say do the outside first? Siminoff suggests
doing the inside first, since you'll then have a nice flat plate to lay against
the workbench when you flip it over and work on the outside. If you do
the outside first, when you flip it over to do the inside, you'll have to
figure out some way to stabilize it.

(I imagine this is very similar to the "do you glue the top or back first on
your acoustic guitar")

Jay

Jay, I was going to ask the same question. I seems easier, to someone who's never done it, to do it the way you and Siminoff say.

Roger does a lot of things backwards. He also glues the ears and cuts the taper on his neck before cutting the truss rod slot. Does that say anything? instead of cuttingt he slot when he has a nice, square neck blank, he works it almost completely, then figures out a way to cut the slot. Bassackward.

Roger uses a CNC to carve his, BTW. I bet it's been a long while since he's hand carved one.

If you carve the interior first, you're them at the mercy of what you did there. You need to carve the exterior, down to fine sanding, then flip it and carve the interior. Make a simple cradle to hold the plate up, or if you wish, cover it with waved paper and press it into fresh plaster to make a support mold. I just set the plate in a bed of planer chips, wiggle it until the chips support it well, and carve away. Or call the CNC guy and tell him i need another plate <bg>

Do the exterior first; it's the right way.

There are several methods and I would posit that the right way is whatever gets you the product you want, in the most comfortable way. In other words, do what makes sense to you. Ultimately outside first, inside first is another version of tomayto tomahto. If you only plan to do it once, I'd say go with your gut because you'll do better if you understand what you are doing better. But if you plan to build more, try any and all methods.
That's my .02.

a) The exterior of the plate is what you'll see the rest of your life. Since it is a complex set of curves, it will look weird if not right. The exterior is complicated, and quite hard to get "right", while the interior is a simple "dome", for the most part.

b) We are trying to hold tolerances to within a few thou, over relatively large areas. If you carve out the interior, your exterior will be a hostage to what you've carved there, and you'll be measuring constantly.

c) 99% of successful carved instrument(mandolin, archtop guitars, violins, violas, chellos, etc, etc....) makers carve the exterior first. There are many, many simple way to hold the plate while you carve the interior.


d) Roger's books and articles(in Frets magazine) have helped countless numbers of us, and he seems to be a nice person. That said, many of his methods and ideas are not mainstream; take them with a grain of salt.Mario38845.4352083333

I agree with Mario here. I built my first strictly by the book (Siminoff's, that is), but I wish I hadn't. I now carve the outside first, I think it is much better.

As far as the original question ("Any tips for carving my first top and back for an A-style mando?"), I picked up a great tip from Andrew Mowry, and that is to rough carve the outside arches with a Safe-T planer from a contour map of the top and back. You can download the contour map from his web site, it's a .pdf document. It is for an F5, but you can easily adapt it to an A-style.

Mowry contour map

_________________
Rian Gitar og Mandolin

What a great resource! I like that these drawings have a lot more contours than Siminoff's. You could also figure the thickess of the plate along each of those lines, and with a little subtraction make a contour map of the inside dome as well. That way you could go in with a router (I don't know much about the safe-T planer but it doesn't seem like it would work inside of a concave surface? does it?) on the insides of your plates before you do any carving and get a lot of rough work done. Then go and carve the outside just right, then come back and clean up the inside. That's more or less the way I do it.

About those drawings, not being very metric savvy, I don't see it on there, but what height would the edge of the instrument be at (I mean the majority of the edge not including the scroll)? With mine I shoot for around 3/16". That would be 4.76 mm. Does that sound correct?

That contour map is interesting. I actually just spent an hour yesterday
transferring measurements from the cross-sectional drawings in
Siminoff's plans to the the top-view drawing and using those to draw
countour lines.

One thing I discovered is that Siminoff's drawings are pretty off; for
example, cross section 1 is far wider on the cross section drawing than it
is on the top drawing. I "moved" the location of cross section1 on the top
drawing based on the width I measured in the cross section drawing. The
others were much closer, but none we spot-on.

Jay, I posted my method for laying out and carving an Archtop guitar top...I think it would be applicable to your application.

Archtop Layout
http://www.luthiersforum.com/forum/forum_posts.asp?TID=4705& KW=anthony+z#forumTop
Using the "Mowry" template Arnt linked you to you could make your own arching templates to check your progress.Anthony Z38846.4874189815

Thanks Arnt and Anthony for the great input, looking forward to build me one of these, all great stuff!

Serge