Why carve a plates outside first?

[putnamm]

(Disclaimer: I was certain this has been addressed previously--most likely in one of the threads I myself started. I did do a search of the forums with a particular eye toward my own previous posts, but I couldn't find a clear answer. It was mentioned previously, but not specifically answered. If I'm duplicating a prior thread, I apologize.)

It seems that most builders first carve the outer side of the plates and then carve the inner side. What is the logic, specifically, for doing that?

To me, it seems better to carve the inside first. The flat area around the rim allows you to set the plate flatly on whatever surface to then carve the outer area. That way you don't have to build a "cradle" to hold the plate or otherwise worry about damaging what you've already carved.

My assumption is that carving outside first results in a more accurate graduation and thereby a better sounding instrument? Is that so? Or is there some other reason?

[Charles E.]

The plates should be carved from the outside first to establish the arching height and the arching profile you want. If you start from the inside first you are working blind.

[amowry]

Yes, you can do it either way, but by starting on the outside it's much easier to have accurate and repeatable arching. For carving the inside you don't need much in the way of a cradle-- a "doughnut" that supports the plate around the perimeter and is covered in cork works fine.

[Graham McDonald]

In a factory environment with machined blocks of wood of regular size where the plates are carved mechanically by a duplicating router or CNC router it would make sense to carve the inside first, by hollowing out from a solid block and then flipping it over to carve the outside to match the inside carving. Siminoff's books suggest that methodology, (based on his experience with Gibson) but it makes much more sense to me to establish the outside shape first and then carve the inside. A support for the edges is not hard to make. I would note that violin family instruments always carve the outside first.

[victor seal]

What Graham said.

[CarlM]

It is also easier to bury mistakes on the inside. If a small piece grain chips or pulls out on the outside then you can take it down and get rid of it if you do the outside first without overthinning the plate. If it happens on the inside it is not as critical to appearance and you may be able to let it go if it is not too large.

If you do the outside last then your choices are leaving a gouge on the front where it can be seen by everyone, filling it which usually does not look so good or overthinning the plate to take it out.

[dhergert]

... I would note that violin family instruments always carve the outside first.

Respectfully, and not to take away from your answer regarding carving the outside of the top first, but I'm guessing that you're just citing violin family instruments as an example, as someone could also cite instruments similar to archtop guitars as an example perhaps?

To be clear about it in case there is any question among readers, mandolins are in the lute family, not the violin family.

[MontanaMatt]

I think Audey Ratliff’s build videos show him working inside -out...
He’s built over 1100 mandolins. Mine is super nice!

[Graham McDonald]

Respectfully, and not to take away from your answer regarding carving the outside of the top first, but I'm guessing that you're just citing violin family instruments as an example, as someone could also cite instruments similar to archtop guitars as an example perhaps?

I chose violin family instrument as an example as carved soundboards on them go back to at least the 16th century, rather than the carved archtop mandolin and guitar which were the invention of Orville Gibson in the 1890s. Although he does not mention violins in his patent application he must surely have been aware of and been influenced by violin construction. I don't know the methodology Gibson used to carve the tops and back when they built acoustic arch-top guitars or how a factory such as Collings does it currently. I would think they would apply the same approach to guitars as mandolins, starting off with a rectangular block of two book-matched pieces of timber machined to a specific length, width and thickness, and having that shaped by a carving machine of some kind.

I am not suggesting that either methodology or another is superior. For me, hand-carving soundboards and backs one at a time (albeit with various power tools) it makes much more sense to carve the outside first and then hollow it out. If I had a CNC router I would probably do it the other way around, leaving a millimetre or so on the inside to be removed by hand to allow for the inevitable variations in the wood.

Cheers

[victor seal]

I think that it is personal preference. If it works for you, cool. I start on the outside to get the arching the way i want them.