A year or so ago I found a very nice type 11 #7 plane at a local antique mall for a reasonable price.
Unfortunately the sole of the plane had a bit if a warp and twist. It worked well enough for roughing stock to dimension but try as I might I could not get this plane to shoot a straight edge.
I have trued the soles of smaller planes before; a tedious task of lapping the sole against a flat surface covered with sandpaper or a sheet of glass covered with abrasive grit. I was not looking forward to spending hours, possibly days, lapping the sole of a 22″ plane.
Last night I came up with two possible solutions.
The first was to contact a local shoemaker to see if I could borrow his night crew to do the work while I sleep.
That didn’t work out so I went with plan B.
I decided to try truing the sole in a manner similar to leveling the frets on a stringed instrument. I lowered the blade and clamped the plane upside down in my bench vice and stoned the sole with diamond stones. I frequently checked progress with a straight edge. I was able to feel the drag of high spots on the sole just as I feel the high spots on frets.
The work went surprisingly fast.
I would not say the sole is perfectly flat but after about an hour of work I was able to make see-through shavings a yard long and leave the board I was planing very straight and flat!