The Kanaban - A VERY Quick Introduction to Our Steel Lapping Plate 

Pretty sure veritas has a steel lapping plate. Diamond plates will also do.

I realise now that the back of my precision 2000 grit diamond plate is a perfect Kanaban, because while it hasn't any grit embedded it is a precision ground steel surface...

How do you keep this flat?

Sure. A diamond plate will also do. As will any machined flat stock steel with a diamond or other abrasive compound, i think veritas even sells steel lapping plates like this one for a decent price.

I found leevalley carries similar mild steel plate(made in Canada) and sold at decent price here in US. Woodcraft used to carry Japanese kanabans but seems out of stock permanently. Yea, I checked the box. It's Veritas made in Canada.

Yes, an excellent question and an excellent point. Your kanaban will wear. Ours have cutting patterns left in the surface by the wash grinder that are between 0.1mm 0.05mm deep. After repeated use, the plate will wear so that these marks become less and less visible, and eventually disappear altogether. This indicates that the plate has been worn by 0.1mm and is out of flat by at least that much. If that is the only plate on hand, I would still use it, especially on smaller tools, or I would reserve it for rough flattening with very coarse grits such as carborundum powder. If you are lapping with fine abrasives (fine lapping powder, #1000 Waterstone grit and finer), I have been able to set up a set of 10 chisels and more on one side of a kanaban without wearing through the grind marks. It’s worth mentioning that most kanaban (ours included) are flat on both sides, so you get two bites of the cherry. As for flattening a kanaban, diamond plates are too coarse and imprecise - at the point you are 0.1mm out of flat I think they would do more harm than good. Reconditioning a kanaban would require a visit to an engineering or machine shop, or a deep dive on how engineers achieved flat surfaces without surface grinding machines. At that point you are hand scraping or using three surfaces and abrasive powders to bring them in to flat with each other. There is no easy answer here as it is a limitation of materials. Getting practicing on a kanaban with fine lapping powder or a #1000 Waterstone will teach you so much about the process, and as long as you stay with those finer abrasives (which I do, not a fan of the coarse stuff) you’ll hopefully get dozens of tools tuned. Hopefully flattening it will only become an issue with lots of miles under your belt.

@@JapaneseToolsAustralia So, okay some or even all diamond plates might be too coarse for flattening a kanaban. But what about other finer abrasives with or on a flat surface? Why would a freshly flattened water stone not work for this? Does it go out of flat too fast due to wear? What about finer sand paper glued to a flat surface (glas, a flat diamond plate or another (flat) kanaban, maybe?) then? That should resolve the coarseness issue of the diamond plate and the wear issue of the flattened water stone, right? If the surface is flat (enough) should it then not work to flatten the kanaban like that? Or am I missing something here?

@@Hoerlimax I think the main problem with using a waterstone for flattening is that it would take too long. You would wear out the waterstone quite a bit and it would become uneven pretty fast. This would mean that you would need a 3rd waterstone to flat the other one and so on. A hand scraper could be more effective here. I used my diamond plate and 1000 grid waterstone for flattening my tools and I must say that it works like a charm.

@@Hoerlimax I use the backs of my diamond plates - after checking for flatness of course. I have also found a lot of cast iron machine tables etc in a metal recyclers yard and am talking to a local engineer to cut a few pieces off and have them surface ground, see how that goes.