stanley frog tuning

[Noah Wagener]

I was wondering what should be the goal in how a blade sits on a frog in a Stanley bench plane. I think i may have ruined the frog. I put blue paint on the blade and put it on the frog to see what areas are touching. when the cap lever is engaged only the front and back of the frog turn blue. I filed away there for half a day and now the frog is convex yet the middle of frog still does not register as touch in the the blade. The cap lever only exerts pressure on the front and rear of the blade. Should i be striving so that the blade is in full contact with the frog when loose? Seems like the middle of the blade is never going to touch blade no matter what. But now maybe i have lessened the pressure on the front of blade by relieving metal there.

THanks

[David Weaver]

The blade will never have uniform contact with the frog. It might be flat enough that it has uniform contact with wet paint that's on the frog, but you just don't need to worry much about tuning a frog unless it's defective, rusty or has a bit of slag on the face somewhere (which you can just lightly file off).

It might still be fine, put it in the plane and see how it works. Ideally, you want the pressure on the blade to be next to the cutting edge at the bottom and right under the lever cap at the top. but it doesn't have to be perfect, and since the whole setup is sprung under tension when you have it tightened, it's only realistic to see how it works when you've got it set up for use.

[Jim Koepke]

... but you just don't need to worry much about tuning a frog unless it's defective, rusty or has a bit of slag on the face somewhere (which you can just lightly file off).

Have to pretty much agree with David on this. The old wisdom says don't try to fix it if it isn't broken.

You should also make sure it isn't an overly curved chip breaker isn't bowing the blade.

jtk