Frog seating

[steven c newman]

Ya think?
Defiance No. 3, tear down 2.JPGDefiance No. 3, tear down 3.JPG

[Doug Dawson]

Ya think?
Defiance No. 3, tear down 2.JPGDefiance No. 3, tear down 3.JPG

So, what's your point?

[steven c newman]

Would you prefer the same plane looking like this?
Defiance No. 3, assembled, side.JPG
Defiance No. 3, clean up 1.JPG
Defiance No. 3, clean up 3.JPG
Different plane, same results, same amount of time to do..
Stanley #3 rehab, frog 1.JPG
the before..and...
Stanley #3 rehab, frog set up.JPG
After.
Stanley #3 rehab, shavings 1.JPG
(with the OEM iron and chipbreaker..)

Been rehabbing planes since the late 1980s....might have learned a thing or two....as to what works...and what is "hype"....

[Robert Hazelwood]

I've always suspected this was overblown. Also they will tell you to make sure the blade is installed and the lever cap tightened- for this to matter it would have to bend the frog casting and then in turn bend the plane body where the frog seats. I'm sure this happens to some tiny extent but it's got to be below the level of accuracy you can get from lapping anyways. That said, for hand lapping there's no reason to take any of it off, so why not leave it on.

I will defend lapping plane soles. The detractors start by declaring that soles don't need even need to be flat and none of the old timers cared about flatness, then in the next breath protest that how you'll ruin the sole by improper lapping, which is so hard as to be all but impossible.

Planes can work well with an out of flat sole...sometimes, and sometimes not. If I had a choice, I'd never choose a plane with an out of flat sole over one with a flat sole, and I don't think any sane person would.

So how hard is lapping, actually? I think it is more tedious than hard. It doesn't take months, but mere hours (or even minutes for smoothing planes). Sure it is possible to do a hack job of it, but we've all seen hack jobs done to things that are even simpler than lapping. The basic rules I'd give are:

- Use a lap that is at least twice as long as the plane (helps speed and accuracy)

-Check the sole carefully before beginning. Measure how out of flat it is, record your findings. This will help you know what the lapping is accomplishing.

-Use a coarse PSA sandpaper, decent quality aluminium oxide. 80 grit is good. Get a long roll (say 4" wide), because you need to...

-Change the paper extremely often. 80 grit will be cutting like fresh 320 grit after a couple of minutes. Seriously, you need to change the paper after no more than 5 minutes of lapping, probably sooner. Complaints about extremely long lapping sessions are related to not doing this, I suspect.

-Hold the plane just like you are going to take a shaving off a piece of wood, and push the plane in a straight line with normal planing pressure. Don't bear down and don't vary pressure front and back, keep it consistent. Only push the plane, lift it up on the back stroke. Don't go back and forth, don't do circular motions or figure 8s. Just a straight push. This helps minimize any rocking, which would produce a convex sole. In truth, off of a flat lap you are going to get a slightly convex sole anyways , but that's fine (even preferable IMO) if kept within reason. You don't want it getting out of hand though.

-Check your work periodically, compare with the beginning measurements. You should be improving things. If that's not happening you need to stop and think for a bit.


The larger planes like a #6 through 8 benefit from augmenting the lapping with spot removal of high spots, using a file, small sanding block, or machinists scraper. Use the lap to identify the high spots, and to smooth everything out at the end, but do most of the material removal with the spot removal tool. There is too much surface area on these planes to get much bite on the sandpaper. The paper on the lap needs to be changed even more often for larger planes.