Plate Ledge

[bkwood]

I'm not certain of the terminology but my question involves carving the inside of the plates, how steeply should one carve down from the ledge where the end blocks are glued. I have been easing them down at aprox 45 degrees, but if I cut them steeper it would leave slightly more area of the plate to resonate. How much does it matter?

[Don Noon]

I don't think you want to carve too thinly near the endblocks.  The arching is steepest there, meaning the longitudinal grain is cut, meaning the wood is weakest and least stiff.  Most Cremonese graduations I've seen show the plates are relatively thick near the blocks, and taper down to the thinnest values near the center of the bouts.  It's what I do, for what it's worth.

[uncle duke]

If you see some of Don's plates where he contoured around the blocks I'd think that would be a safe way to go.

    The template I have for the slope around the tailblock looks like a shark fin.  Like glue/centerline 13mm from block edge tapering to zero at the rib/block join.  So using a pencil draw a sharks fin profile to follow when sloping.

  My neckblock appears to be 16mm x 52mm or so.  The belly plate slope area also has a 4.1mm plate thickness at the block edge but shows no taper.  Obviously put a taper there leaving some perimeter slope wood for strength.  My plan says thickness at the bottom of perceived slope is 3.0 mm.  Just make a strong slope I guess following the block contour.

If I'm remembering rightly my slope thicknesses around the blocks were somewheres in the range of .125 to .140.  - that's right above 3mm for thickness. 

[Conor Russell]

Looking at old  violins, it's  often surprising  how the line  can flow from the block gluing surfaces  down into the body of the plate without  a severe ledge.  In other words, the block gluing platform  can flow into the rest of the plate fairly smoothly.  The inside  of  the  plate  reflects the outside, and there's  just a little thickening  at the middle of  the  block. This can hold true, even when the arching rises quite strongly  from the ends.

Avoid having to make a ledge around the inside  edges  of the plate to achieve the  thickness you want. Take a look at the scanned  images of great violins, and plan to achieve that profile.  The block platforms will  flow from there.