Reply To: Flattening longer plane soles
I had to flatten a #7 after I had it welded ( broken cheek) that had a 1/16+ Concave bow in it. I had no qualms about using the belt sander on the ends until it got in hand sanding range. Just don’t let the iron body get too hot, and use something like a 36 grit belt.
When I switched to hand sanding the sole, I went to the glass shop and asked for a 1’x2’ piece of float glass, which is very flat. And used psa sandpaper strips. It still took a couple hours going through the grits.
You can also go to a granite counter shop and ask them for a sink cutout. They usually send those to the landfill and will likely give you one. Black granite tends to be harder and flatter, because a not flat piece show odd reflections.
Technique also counts in jointing edges. You need pressure on the front of the plane at the start and at the rear of the plane at the end of a swipe. Pretend you are trying to scoop out the middle.
