Hi Steve -- I picked up this tip from David Weaver in one of his wood plane making videos. It just makes use of a chunk of 2x4 that allows you to bear down hard on whatever medium you're using to flatten. I use anything from diamond plates to 80 grit self stick sandpaper on a granite block. It really saves wear and tear on your fingers.
I was lucky enough to come across a chunk of cast iron 1" X 3" X 12". The local community college machine tools course students flattened it for free. So far the only cost is for the diamond paste, about $12. Even 15 micron past made child's play out of a 2" chisel.
Patrick, yep, it's the Sigma 120. And i will use it on stones that are bunged up badly, but not on new ones. It's nearly as fast as a grinder on bevels, especially since there's no chance of drawing the temper of a blade.
This is brilliant! I guess you'd have to keep your sharpening medium on the edge of your bench though since the screw heads protrude. Steve Graham I feel your pain though, I just went through the exact same thing. 60 grit sandpaper helped some but it still takes forever.
You're correct, Steven. Actually I use a holder for the diamond stones that elevates the nuts and bolts enough so they don't contact the bench surface. When using sandpaper on the granite block it's off the edge of the bench. Most vintage plane irons I've acquired have needed a lot of work. This basic little jig has has really saved my hands.
9517K496 for the steel. It's a 4x24 piece that I cut into 3 8x4 plates.
I get my diamond paste from a mix of McMaster-Carr (Sandvik/Hyperion), PSI, and Norton. McMaster is probably the most cost-effective source for quality monocrystalline compound.
As it turns out David Weaver, perhaps inspired by this thread, just uploaded a video to YouTube that shows his jig that inspired me. Do a search for " The best way to flatten a plane iron." David's jig has longer handles but he explains that one needs to hold the jig firmly on the center of the back in order not to rock it on the medium.
Unless the chipbreaker is also bent....BTDT.
A LOT of these old vintage planes have just sat around on a shelf..for YEARS. Left with everything cranked down type, and half the time put together backwards. Lever cap slowly over time (Decades?) will bend things out of shape, simply because someone had cranked that bolt down as far as they could. Have seen many an old plane come through my shop with this sort of "treatment". Can't move the lever cap, without having to turn the bolt completely around four or five times. Chipbreakers mated to the bevel side of the iron, with enough junk under them to build a decent sized No. 2 pencil. Then, they leave it where a waterline can drip on it, or near an open window. Then just forgotten about until a yard sale day comes up.
Seen too many of these things. Then I get to clean up the mess...
The irons I am fooling with right now are for a Stanley 57R and a 151. They are pretty thin. I like that jig thing. May try it.
I have a big block (4" square and over a foot long) of 1018 sitting around doing nothing. I should flatten one end side on the mill and see if it works for lapping.
Cry "Havoc," and let slip the dogs of bench.
I was socially distant before it was cool.
A little authority corrupts a lot.