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This is a luthier tool and I know it’s not for everyone, but I’m thinking that there might be some clever people here who just might find their own use for it.
Electrifying a Radius Dish Sander
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30 seconds spent cutting off the corners will save a lot of recovery time when one of those corners smacks into a finger
excellent addition to your shop: (I agree, those knuckle buster corners should be removed).
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This dish is also a part of my go-bar deck. I've already made another dish that I may use so that I don't have to disassemble the go-bar deck everytime I need to sand. It actually is not moving as fast as the video makes it look. That motor is variable speed so it may eventually be set slower.
So ... why is it called a dish sander, and what are you radiusing? Seems like you are sanding it flat, level … i don’t see a radius.
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Yes, no apparent "radius" for me either. It's more like a chamfer or a bevel. This is because the fronts and backs are crowned surfaces and need to sit on a corresponding angled surface. But, I'm no luthier, I just play chords on a guitar.
The sanding surface has a "dish" to it as he says here:
Whether your are "radiusing them or just sanding them flat .....
The sanding surface has a "dish" to it as he says here:
Whether your are "radiusing them or just sanding them flat .....
It's a radius. The braces are also sanded on this radius and that helps to shape the plates for the top and back of the guitar, or uke in this instance.
A 'flat top' guitar typically has a radius of 12' to 18' and the back is usually 25' to 32'. It helps with the sound and also makes the instrument stronger, better able to withstand the string tension.
A 'flat top' guitar typically has a radius of 12' to 18' and the back is usually 25' to 32'. It helps with the sound and also makes the instrument stronger, better able to withstand the string tension.
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So that means there's a curve to the top edges or a radius. But it's very slight, with a leg of 12 ft or 18 ft out from the center of that size circle.
The dish duplicates that curve on the top edges of the sides and all around so the front and back will sit flush.
Right? Only a luthier would know this.... LOL.
Yes sir, and it's easy to see when you look at a guitar from the side.
Much in the same way that when you see an empty flat bed trailer you can see it's got a crown to it and it's not really flat. In that way it is better able to handle the stress and load when it's carrying weight.
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A flat top acoustic guitar, does not have a flat top, it has a slightly curved top. So, the mating surfaces on all the edges must conform to that curve/radius.
The sanding dish/disc has that curve "built in", so when it's powered it requires so much less elbow grease.
A violin, cello or bass fiddle also called an "upright bass" or double bass, has a very pronounced curvature to the top. A bluegrass mandolin has a flatter top and bottom, but some others have a large belly on the bottom. I think those are European in origin, my mom had two of them which I inherited.
Concert instruments have formal names but bluegrass instruments are identical and have names like fiddle rather than violin.
I call my upright bass, a bass fiddle.
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Does the radius form a portion of a spherical surface or is it an arch from end to end of the fiddle body? If the former, is the MDF square for the sandpaper slightly cupped for that big radius and how is it cupped? If the latter, I don't see how the mechanism does that.
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This isn't my video, but it is one on YouTube that shows how the radius dish is made.
Guitar backs and tops are in the 0.100" to 0.080" range and easily conform to the large radius. I don't know the thickness of uke backs/tops but my assumption is that they also conform to the specified radii.
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