Lapping chisel and plane blade backs - a few tips
Having dug out a few divots from the fingers I thought I'd share what I've learned.
I now wear rubber thimbles. Good with water lube; useless with oil though.
Use a thick rare earth magnet to improve grip. IIRC Derek has posted about using a magnetic dial gauge stand for plane blades. This is prob where my idea came from.
This magnet is a thick ring as you can see in the pic. Works well: fingers either side or one in the hole. Doesn't really stick well though with BE chisels under about 3/4".
It actually has enough pull to hollow a Stanley blade against a diamond on metal substrate. Not recommended.
I'm on a roll with some new stones and doing a deal of lapping and polishing.
In the pic is a 30mm wide Muji HSS blade out of a palm smoother. Again I found that their steel is darned hard, or should I say abrasive resistant. Took 300 strokes to flatten on a newish coarse DMT stone. More than double that to polish up to 8000 grit (fine diamond, then ceramic #1000, #4000, & #8000).
Some other impressions: the Hock A2 Cryo blades are more abrasion resistant (OK, sample of 2 only) than Veritas A2 (sample > 6). The 2 Hocks needed lapping; the V. only need polishing.
With exactly the same back and bevel polishing procedure, the Veritas O1 feel sharper to a finger stroke than their A2. Best guess is that the alloy grain is coarser so there's more resistance to the skin stroking over it. No diff in producing galoot pattern baldness that I can see but I'm getting to the stage of losing skin with this test :(
The ceramic #4000 (Shapton Glasstone) is a sod for stiction, even with a drop of liquid soap. Not impressed. Circular movements reduce it quite a lot though. The ceramic #8000 is a Sigma which also produces a deal of stiction. OK, this work should only have to be done once in my lifetime so no more whingeing :wink:
To speed the hard work up I've tried Scary Sharp and found it unreliable. Too easy to get more abrasion on one or both corners which just generates more work to take the rest down. If I continue with this obsession a very coarse diamond stone is what I'd go for.