To regraduate or not...

[Matthew Tucker]

Ah, but in a fifty years time there will be a rumour going around that Loveri DID make bows, because there are some bows around with his name stamped on them!

Perhaps the Amati was attributed deliberately after a maker who never made basses?? Anyway, I'd be interested to see the appraisal. Have you seen it, Arnold?

OK Ken, I had mis-read that your tip that leaving the "shelf" under the bass bar was an inherently good thing, instead of just "working around the bar" to improve the thicknesses.

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate. The edges of the bar are sheer and clean right down to the new thickness. If I was to do it again, I'd remove the bar and put a new one on after regraduating. It was very fiddly working neatly right up to the bar, and replacing a bassbar is no big deal in comparison.

[Ken Smith]

Originally Posted by Matthew Tucker

OK Ken, I had mis-read that your tip that leaving the "shelf" under the bass bar was an inherently good thing, instead of just "working around the bar" to improve the thicknesses.

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate. The edges of the bar are sheer and clean right down to the new thickness. If I was to do it again, I'd remove the bar and put a new one on after regraduating. It was very fiddly working neatly right up to the bar, and replacing a bassbar is no big deal in comparison.

Matt, in the case of the Gilkes, the platform was outside the glue line about a centimeter or so all around it. I didn't measure it but when the Top was off and before the new 'Bar went in, I felt around the 'Bar and 'Post areas and commented to Arnold how unusual this was. I suggested (which he probably had planned on anyway) that he leave the platform relations as-is during the 'gentle' re-graduation and keep the makers 'idea' as original as possible. The Gilkes was estimated for its wood and arch strength at about 200% the necessary thickness and ended up at about 120% the thickness it would be if made today. The Bass sounds deeper and fuller now and still strong as a tank. The Bass could probably easily survive another 20% of scraping and the removal of the shelf but, why fix what isn't broke? The Bass sounds great now and at 195 years old just needs to be played steadily and break in again. This is a Bass that does not have any belly splits. I plan on keeping it that way if I have any say in it.

[Arnold Schnitzer]

Originally Posted by Matthew Tucker

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate.

Matthew, keep an eye on the top in this area. I'm afraid you may have inadvertently created a fault line which could cause a crack. This is the same reason why patch edges should not be finished parallel with the grain.

[Matthew Tucker]

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.

[Ken Smith]

Originally Posted by Matthew Tucker

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.

I think Arnold means that if the platform is at a right angle 90 degrees with the Bar directly under it, sitting on it, it acts as a pressure point along the edges or the 'bar joint. I think that is what he is referring to rather than a gentle sloped platform in which the 'bar would sit. That's how the Gilkes is done. You can feel it but you can't see it that easily. It is slight but it is there.

[Arnold Schnitzer]

Originally Posted by Matthew Tucker

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.

Yes, I see your point. I was thinking the cut-out under the bar was following the grain, but this is not really so. Anecdotally, though, I have seen a bass where the regrad was done this way and the top cracked badly. I remember it being pretty thin. And the wall of old top wood on which the bar sat was a good 4-5mm high.

[Matthew Tucker]

I've taken off from 1mm going to 2mm at the tips. I'm not worried structurally, but as I said, I don't think I'd do it again that way. And your words of caution are duly noted!