Lapping The Sole of a Hand Plane

[onocoffee]

As I've been exploring hand planes, I've ended up with a few vintage planes. I think I have successfully restored a couple of cheap, 1970s era Stanley No. 4 planes - but I don't really know what I'm doing other than watching videos. A few months ago, I found a Craftsman/Millers Falls No. 3 and started to work that. My understanding is that you want the nose, as well as the front and back of the mouth to be flat, but how far back? On the No. 3, the tote has a bump out on the back of the sole. That tail end is significantly "higher" than the rest of the sole. Do I need to flatten all of that? Is that critical? Or just flatten ahead of it across the width of the sole?

And while my understanding is that smoothing planes (3 & 4) need to have flat soles, how critical is that for the larger 6 and 7 planes? I do have one of each that will need attention.

I worked this No. 3 last night and while I think it's a fascinating journey, it is a lot of work. A lot of work that makes me think that perhaps I should only buy new Veritas or Lie-Nielsen planes in the future!

 

[Packard]

We used to shave the heads on my go-kart engine by rubber cementing emery cloth abrasive to a sheet of smooth glass. Glass it typically very flat.

Then it was a simple gliding the head back and forth until it was smooth.

Of course the heads were aluminum, so it cut fairly fast. I think you can get a small amount of bow out of a steel platen with that same method and a lot of patience. You should try to find a steel cutting abrasive cloth. And I would only use this method to take a couple of thousandths off, espeially if there is a low point somewhere in the middle.

This is an atypical method that worked 65 years ago on a racing go kart by a couple of 13 year olds, so take it for what is it worth.

 

[jeffinsgf]

I would chase that #3 a little farther. You don't need every bit of the bump-out for the handle, but I would want the pitting right in front of the blade opening gone.

The sad part about this job is, the closer you get to finished, the slower the work goes.

 

[jeffinsgf]

Just to add...

I have a couple older planes where I've worked on the sole and gave up on them when they were close. You know what? They cut pretty well. A sharp iron, properly aligned makes as much (or more) difference as a perfectly flattened sole. That's not an excuse to work with a warped sole, but perfection is the enemy of completion.