Best way to flatten the back of a chisel

[SlashDev]

This is a flat chisel!  Took me a while to get it this flat.  ha ha

I bet those eyelashes popped right off.

[SeanA]

I used the same technique Timberwolf suggested. Considering his mad skills, I'm pretty proud of myself for thinking of it too. (-:

That said, I had a lot of trouble with it and pretty well destroyed a Marpes/Irwin chisel.
1) it is hard to get a consistent flat reference surface on the curved back. Previous commenter's suggestion to grind slight hollow might help
2) esp with narrow chisels, it's too easy to let them rock imperceptibly to round or "dub" the side edge/lands. And a subtle rocking is hard to ID because the scratch pattern is even
3) platten may not be flat enough, or the paper over it may not pull flat.
4) desperate, I tried feeding straight from the end of the belt grinder. Got a nice arc to the blade now!

I suggest fixturing chisel in drill press vise and using an end mill to get it coarsely flat. Then stones. (Havent tried this yet)

[Kansas City Fireslayer]

Easy to mess up a chisel real quick using power unless you’ve mastered the learning curve with plenty of practice. The safest and most predictable way, IMO, is the granite lapping plate with adhesive spray on the backside of wet dry paper. I have ruined a few tools under power, btw....

[Alan S]

I don't have a CBN wheel for a grinder, but since those are made by bonding the grit to steel or aluminum, it would seem the usual problems of grinding on the side of a wheel would be absent. Might that be a good choice for such flattening?

I was thinking of something like this:
https://woodturnerswonders.com/collectio...-cbn-wheel

[crokett™]

I don't have a belt sander but that is what came to my mind as the obvious solution.

The foot switch is a good idea.

I do.  You can come use mine.  I'll even get a foot switch for it.  

[Peter Tremblay]

I do.  You can come use mine.  I'll even get a foot switch for it.  

That's the best idea yet!