Diamond Chisel

[tardis86]

anyone know how to sharpen diamond chisels? my son dulled the points on my 4 hole chisel and i need to know how to sharpen it. i don't know how to get into the sides of it if need be. thanks!

[Art]

Never tried one of those. Will diamond files fit. They make some pretty thin ones. Also, sanding disks on a Dremel or Foredom. Go gently (rpm wise) as those things will deconstruct if you run them too fast.

Art

[zuludog]

I assume you're talking about a stitching chisel with diamond shaped cross-section prongs

Use a flat needle file followed by wet & dry paper glued to a thin sliver of wood or stiff plastic or aluminium. Work your way through a couple of grades of grit; say 500 then 800, but anywhere around those will do

Take your time and it can be better than new

[King's X]

There are several videos on YouTube that will help you sharpen your awl.

[gojosh]

There is a serious misconception - diamond chisels are completely different than any of the things anyone has called out. They are not thonging chisels and the points are very fine and close together. 

I'm wondering if something like these would work:

https://www.sharpeningsupplies.com/Norton-Carving-Tool-Slips-P268.aspx?gclid=CMX73tL42MwCFQmQaQodRmoF_w

 

My biggest concern would be making sure that you don't end up with tips shorter than others.

 

[zuludog]

I've found the needle file & abrasive paper method I described works OK

The small sharpening stones in the link also look OK

I've never tried this, but if you want to use a stone you could search around a second hand stall for a cheap old, worn stone and break it up with a hammer. You'd be bound to get some suitably shaped pieces, and it would be cheaper than paying approx $10

[silverwingit]

It's far from ideal but it works. I've found that the only way to get a regular stroke along the full length of the tines of a diamond stitching chisel is as follows. The difficulty, of course, is sharpening the surfaces between the tines.

I take a thin but wide stainless steel ruler without cork backing and hold it tightly onto the edge of my workbench or granite block so that there is enough of the ruler sticking out over the edge to insert the tines to their hilts. Then I take a strip of wet or dry sandpaper and place it on top of the ruler to that it is flush with its outer edge. The new 3M paper has a mildly sticky back that helps you keep it adhered well enough to the ruler but it's a bit thicker so it may not work with tightly spaced tines. Plain old sandpaper is thinner but it would probably need some double sided tape to keep it from sliding around on the ruler. Or maybe tape both ruler and sandpaper to the granite block.

It is a tedious and time-consuming process but you can use the usual progressively finer grits of sand paper to achieve nice smooth surfaces between tines. You will soon develop a "feel" for when you have the chisel at the proper angle so that the inter-tine surface you are working lies perfectly flat on the ruler. As usual move your arm, not your hand or wrist to generate nice, long even strokes, maintaining the proper angle so that the surface you are working remains in full contact with the surface of the sandpaper. In order to sand the inter-tine surfaces all the way to the point you need to tilt the chisel with respect to the ruler towards the end of your stroke. There are twice as many surfaces you must treat for the number of tines on any particular chisel, counting the two outer and all the inter-tine surfaces so be prepared for a long session for each chisel.

When you're satisfied that all the inter-tine surfaces are smooth with, say 400-600 grit sandpaper, you can apply some polishing compound to a piece of 3x5 card and use it with the ruler to polish the hard to access inner surfaces. Sharpening the outer surfaces is much easier. You can simply drag the flat surface of the chisel along the sandpaper or strop, tilting the chisel upwards at the end of the stroke to sharpen all the way to the points.

I've been quite surprised at how rough even expensive pricking irons all the way down to cheap Chinese diamond-shaped stitching chisels are. It's not so important with a pricking iron but since a chisel goes all the way through the leather, those rough edges are problematic when it comes time to pull the chisel out. A rough chisel will go in easily enough when driven with a good maul, but removing it is another story. You need to use so much force and tilt the chisel back and forth so vigorously that you can easily bend or even break a tine. A chisel with a bent tine is trash.

Once you've polished one chisel you still have the rest of the set to do. But when you're done your chisels will be a dream to use. A quick poke into a block of beeswax and they will be easy to remove. I do find that it is still very important to pull even a sharpened chisel out of the leather with force that is perpendicular to the surface of the leather. Tilting a chisel back and forth to remove it will eventually damage it so if you do have to tilt, do it in multiple passes tilting to very small angles one way and then the other. Think of tilting only to break the static friction that holds on the chisel. Stop your tilting action as soon as the static friction is broken, and use only that steady perpendicular force to finish removing the chisel. Even with good quality Japanese chisels it is very easy to bend an outer tine. Once bent, they're useless. Try to bend the tine back so its parallel and it will break off. You can tell I've ruined more than my share of stitching chisels!

Give it a try and let us know if it works for you.

Michelle

 

 

 

Edited May 14, 2016 by silverwingit