Chisels and edge chipping

[Brian Holcombe]

I haven’t tried it, but it seems like something interesting to try. Only thing however is that it may well have no effect on Japanese tools

[Stewie Simpson]

I ask because Chromium Oxide is a gentler abrasive than AlOx, so I suspect that 0.5 um CrO film or a pure CrO compound (read: Not the stuff that comes in a green bar) could get similar results.

I seem to recall a prior discussion that didn't end well.

I am loathe to mention the topic of Pure Chromium Oxide Paste as being superior to what's being offered in the wax stick base, but here goes.

The following is the Leather Stropping Block loaded with the PCOP. A finger tip dipped into the paste was enough to coat the full top surface of the strop.





And here is the Pure Chromium Oxide surface after stropping a bevel up Stanley Block Plane Iron.

[Patrick Chase]

I haven’t tried it, but it seems like something interesting to try. Only thing however is that it may well have no effect on Japanese tools

Cr2O3 hardness is Mohs 8-8.5, in the same range as Al-Oxide. It's quite a bit harder than either SiO2 or a Japanese tool.

Like SiO2 it's an inherently slow abrasive, but it will have an effect.

[Patrick Chase]

I seem to recall a prior discussion that didn't end well.

Yeah, but that doesn't mean we can't get it right the second time.

IIRC where we got stuck in that previous conversation was on the ever-contentious topic of whether the green bars were useful at all. How about we just accept that the stuff works well for some people (George for example), and focus instead on how pure Cr-oxide compares to JNats for edge life in Japanese tools?

How do you like your Cr-oxide paste after having used it for a while? I use 0.5 um Cr-oxide lapping film sometimes, and while it's slower than AlOxide (and waaay slower than diamond) it seems to leave a nice finish.

[steven c newman]

Best part of why I like to buy vintage chisels.......the "bad steel" is long gone. About half of mine are pushing 90 years old.....

[Jim Koepke]

Best part of why I like to buy vintage chisels.......the "bad steel" is long gone. About half of mine are pushing 90 years old.....

If the various studies mean anything a couple of my mortise chisels are pushing 200 years. My scythe was made before 1860 and some of my Buck Brothers gouges were made before 1870. We should looks so good when we are that old.

jtk

[Patrick Chase]

Cr2O3 hardness is Mohs 8-8.5, in the same range as Al-Oxide. It's quite a bit harder than either SiO2 or a Japanese tool.

Like SiO2 it's an inherently slow abrasive, but it will have an effect.

Continuing my thought, IMO CrO2 is best used in a manner similar to how you use your JNat polishers: Do the bulk of the sharpening on something faster-cutting, and then finish on the gentle abrasive to "round off" the final set of striations. If you use it that way then cutting speed is almost irrelevant.