Violin Forum/Message Board

John Cadd · Posted: Fri Feb 16, 2024 4:12 pm Post subject: Sharpening chisels

There is a simple trick for sharpening plane irons. Lay a tin steel ruler on the side of a diamond plate and hone the back edge to make a tiny reverse bevel . That`s well known already .
For some reason the same trick is disapproved of for chisels. But there is a difference . If you lay the ruler across the end of the plate with the chisel blade laid along the plate --full length You can sharpen the end of the back without spending hours trying to get the back flat . One snag arises with older chisels that were hammered to death when they were produced . The surface near the handle may not be exactly parallel with the blade edge.You can see a shiny spot on the left side near the handle with a shiny spot diagonally opposite on the edge. If you have a Dremel you can work that high spot down to match the edge .Once the handle end and edge are matching the chisel can be sharpened with a consistent flat back section near the tip. That applies if the older chisel has rounded edges all along the back .
The length of a chisel blade can be the radius of a circle.Work out the circumference of that circle and compare that to a 1/2mm thin ruler .You can work out how small the angle on the reverse bevel is .But the chisel can maintain that shape for many years without getting a steady increase in curvature that will happen with many sharpening methods seen on youtube .

John Cadd · Posted: Sat Feb 17, 2024 10:39 am Post subject: Tools

In case you want the exact reverse bevel angle .Assume the chisel blade is 20 cms long.The circumference of that radius is about 125cms.The ruler is 0.5 mm so the full circle of 360 degrees is divided by 250 (125x2). That gives just under 1.5 degrees angle at the tip of the blade . That is controlled ,for several years ,between the tip and handle end so there is no chance of wobbling .To be pernickety change the upper bevel angle to 28 .5 degrees for a working 30 degree cut .

John Cadd · Posted: Wed Apr 16, 2025 7:14 am Post subject: Violin making tools

Some helpful home made tools or jigs are only seldom used , and even if you made them yourself it is a mystery what they are for. I began writing the use of each jig on the thing itself . Yesterday I was using a kind of large bench stop.It was to work on the violin plates and stop them sliding away as you cut . The back of this was a block of wood covered in leather . Two screw holes were "explained " in writing to fix the front edge against the bench.The top of the block explained it`s use and even a reference to Ed Heron Allen `s book and the page number ! .

John Cadd · Posted: Sat Sep 13, 2025 9:42 am Post subject: violin tools

One difficult part of purfling is the point of spruce inside the bee sting area .It`s where the spruce will break away if the knife is drawn along outwards towards the bee sting . Straight knives will not leave an internal curve alone and tend to catch those unprotected points. You can make sure the knife cuts inwards. That is an inprovement. But a straight edge is still looking to damage a curve.
So copy the Japanese gouge design and sharpen the internal bevel shape which leaves the end of the gouge in a curve. A photo here might disappear but you can look it up on a site showing these Japanese gouges . The curved edge will allow some roll to help a clean cut while the blade is already inside the groove.
Sotomaru Nomi Incannel gouge is the name . Modern makers are now copying the western model which are far harder to sharpen . The Japanese style can be sharpened on a flat plate .

Michael Darnton · Posted: Sat Sep 13, 2025 10:23 am Post subject:

As soon as you make the first smallest incision in the point area lay on a drop of super glue. This turns the fragile tip instantly into plastic and it shouldn't break off from there on. Traditionally hide glue is used for this, but it takes longer to dry.
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John Cadd · Posted: Sat Sep 13, 2025 12:22 pm Post subject: Violin tools .

In a video by Clive Titmus about Making Lute Pegs he uses superglue to correct mistakes when reaming the holes .That is an epic film with a mountain of skill .
But cutting those little points still needs a tool for the shaping before or after the superglue.
I was sorely tempted to fit plastic laminated purfling with superglue on the repaired violin . I managed to resist that. It was so easy to test the purfling fit straight out of the packet without any heating . It`s useful as a Go-No go check on the purfling depth and width .