Straight from the horse’s mouth
I am an ex-engineer; 4 year apprenticeship; worked as a toolmaker for 10 years.
Why can’t they keep the chisel cool with water to stop it bowing? I used to grind hundreds of punches and dies etc, on a Surface Grinder using coolant (a mixture of soluble oil and water) to keep the cutting edges cool.
I was always taught that you should never grind a chisel or plane iron on a: bench grinder/disc sander/linisher. Yet all woodwork mags show this; I’ve even seen an advert from Robert Sorby in GoodWood saying that “using our linisher to sharpen chisels is a tried and trusted way”!!! The problem is, even if you use a cup of cold water to dip (quench) the chisel in (in engineering this cup is called a dashpot) the thin edge of the chisel (the cutting edge) overheats very quickly and will lose its temper, thereby softening it.
I know about hardening and tempering and am totally confused by this information. What do you say? How do you remove a chip or knick from a chisel or plane iron if you don’t have a Tormek?
This is the problem – you put your finger right on it. We have a Tormek, and a conventional grinder in the shop. Students generally use the very safe water cooled Tormek but, as they get better and understand, they move over to the conventional grinder. We set it up with a very cool running wheel with a slightly domed surface. We use a diamond tool to shape the stone and clean it. The tool goes on a shop made jig that puts the blade at 25 degrees and allows a free sideways movement.
This is key, as the stone is domed very slightly, it only cuts at one point in the centre. The tool is moved over the stone gently side to side and checked for coolness. It cuts faster than the Tormek; I’m 63 this year and life is too short for slow water cooled grinders. I am convinced that a well set up grinder is the way to go; we don’t burn our edges and we grind pretty quickly.
Hope this helps Kevin could I post this as I think it will help some others to get this important issue sorted.
All the best,