Thread: Fixed width dovetail templates

from what it looks like ,its a scan of a cheep china violin , still good
the violins i make are from Carbon fiber and there are a few desighn problems just coppying a timber one , the raised rim around the out side of the plate has to go , made from carbon fiber it restricts the twisting and the violin ends up too strong , im useing his neck / scroll fingerboard

the one im drawing is a 1701 stradaverous , the shape was set out the way he was tought to draw them durning his aprentiship , the curve shapes were pulled from CTscans of the instrament , its just the way he has scolliped out his lower side of fholes has me scratching my head how to get the curves right , easy to do with a chisel and scaraper but in cad i have to find 2 3D setout lines ??/its a bugger??

the shape of the violin was drawn from instructions out of a printed book , but similer to this volia http://kigiri.free.fr/tdl/page3/files/page3_5.swf click on the orange arrow for the steps

the scolloping out of the fhole

After quite a few mal-adventures, I finally got the two parts of ONE of these jigs to fit into one another.
I started with the ordinary Koala ears, but that got nowhere fast.
I then tried the square Koala ears and got better results, but still had a gap of about 1mm all round the joint.
I tried doing 0.1, 0.2, 0.3mm offsest but nothing appeared to improve the situation. I then tried a 1mm offset and that overimroved the fit so much that it didn't even look like fitting.
So, I then started out with a standard set of tails and endeavoured to cut a set of matching pins. First 0.7mm oversized, the 0.5mm oversized and finally, 0.6mm oversized. the last one finally worked. It still didn't make a perfect joint and it may be that I need to try a 5.5 and 5.75mm offset, but it is finally getting there.
The left side of the picture is a 0.5mm offset and for some reason, all of one side of the ears broke off when being machined. The other side is 0.6mm offset and is a lot better, but just a fraction tight.