Hi David,

Yep, oil stones wear. Don and I were talking about this today and he pointed out that we probably dress our oil stones as often as he did his water stones.

I think what's important is that the topography of each stone matches the others. I used to spend most of my honing time getting the tool to conform to each of the stones I used. Having them uniform is a huge time saver and makes sharpening quick and easy. Of course the initial preparation of each tool is the price of admission to quick and easy sharpening.

One thing we talked about is that water stones wear so fast they may conform to the shape of the tool rather than the tool having to be honed to where it matches the topography of the stone. I'll have to think about that before I decide if it could be an advantage.

I do know one thing. Most days I'd think twice about reaching into a tub of water to flatten water stones. Being somewhat of a klutz who probably shouldn't be allowed to play with sharp things, I usually sport a few Band-Aids. Do you have any idea what it would cost to keep me in Band-Aids if I had to change them each time I dress my honing stones?

For the initial work on freshly heat treated irons, we've been using a coarse India for a year or so. I bought it with high expectations then was disappointed at how slow it cut. We didn't do much with it until we figured out its factory faces don't work without dressing first. It requires frequent dressing but it cuts faster than any stone I've used. You might find one helpful with that chisel.

Larry

Larry,

Thank you so much. I have seen whole sets of chisel backs and plane blades ruined because the tool backs conformed to the shape of badly hollowed waterstones.

This topography issue is very important, and I was always frustrated by clear differences in a set of diamond stones that I have. The scratch patterns changed radically between grades indicating differences of shape. I have also had this issue with the ceramic stones.

The concept of a factory glaze on a new stone makes perfect sense. I am itching to dig out and dress my coarse India stone.

What make and grade of diamond stone do you find best for the dressing and flattening please?

Best wishes,

David

David,

I use the 8 inch extra coarse DMT, I believe it's supposed to be 220 grit. I'm not sure how flat the double sided diamond stones would stay when flattening another stone.

I've been asked a few times if dressing my hard Arkansas with the coarse diamond stone makes the fine stone more coarse. It probably does, a little. I believe that added coarseness wears away with just a few passes of what ever tool you happen to be sharpening.

After years of use, I ordered a new diamond stone this morning. I actually caused most of the wear to my old one when I stupidly used it to flatten the sole of a Stanley shoulder plane. The swarf from grinding or honing steel or iron is stringy which wears a diamond stone quickly. The diamond/bonding agent matrix that holds diamonds in place is designed to wear easily and quickly so that it exposes fresh facets of the diamonds as layers of facets fracture and spall away. This matrix was designed to work with swarf that's granular like generated when dressing carbide, stone or other hard and brittle materials. I lost a pretty high percentage of diamonds on the diamond stone I'm replacing by using it on iron and steel.

Another way I abused my old stone was using too much pressure. Diamonds are too brittle to handle a lot of pressure and facets spall quickly if you use much pressure. I've learned to use little more pressure than the weight of my hand. A lot of pressure just wears the diamonds away and won't make them cut faster. Unlike the almost pyramid shape of most abrasives, diamonds are more like faceted spheres and this isn't suited for rapid stock removal. You can't/shouldn't force diamonds, be patient and let them do their job. The single advantage of diamonds is they'll cut almost anything if you're patient enough. My coarse India cuts steel a lot faster than the diamond whetstone.

I learned all this trivia from a technical representative of the company that makes the diamond wheels for the oscillating diamond grinder we use in our metal shop. It's designed for sharping carbide metal cutting tools and I was using it to grind the clearance angles on the sides of our plough plane irons. I contacted him because I was going through pretty expensive grinding wheels very quickly. He told me I could extend the life of the wheels a little by hardening the irons before I ground but he still didn't recommend grinding normal tool steel with diamonds. I don't do that any more.

Larry

Larry,

Thank you so much for that detailed explaination, which confirms absolutely my initial experience.

Would that that technical information had been clearly available when I bought my first extra coarse black diamond plate.

They seemed to be the answer for everything, and I also ruined at least one trying to flatten plane soles, and even the backs of A2 plane blades with too much pressure.

Best wishes,
David

David,
Any chance of putting a photograph of the dovetail saw that you had made on your website, I`d also like to know if it is performing well.

Many thanks,
Mark.