Replies

1. 
   JohnWW | Oct 06, 2008 02:20am | #1

   Sloatsburg,

   Personally I think that plane sole flattening is becoming a fetish whose benefits aren't at all proven. I've read a dozen articles on the subject, and hundreds of postings on sites such as Knots and I have yet to see a single claim that the plane actually worked any better after having its sole flattened.

   In theory, a sole that isn't flat might allow some excess tearout in especially hard to plane woods and a sole that is badly out of flat might have trouble creating a straight edge, but a perfectly flat sole is hardly a necessity for most woodworking. For centuries planes had wooden soles that simply couldn't be kept flat and yet vast amounts of furniture were made with those planes.

   In any case, from a machinist's point of view, most of the techniques I've seen recommended for flattening a plane's sole aren't likely to do the job well. The only technique that can be used in a typical shop is to grind the sole on a flat surface covered with an abrasive, typically sandpaper. The problem is that almost all of the flat surfaces I've seen recommended for doing the work on aren't reliably flat, this includes glass plates, granite tiles, diamond stones, and the cast iron tables of woodworking machines. The thinner materials, like the glass, granite, and diamond stones, will flex under the pressure of grinding, and a lot of cast iron tables aren't as flat as we would expect them to be, I know this from having tested hundreds of machines over the years in the FWW shop.

   If you are going to be serious about flattening, get a machinist's granite surface plate to work on. They come in all sizes, but one 12" by 18" by 3" thick weighing 85 pounds and costing a little over $100.00 plus shipping would do the job, these are Chinese imports but are guaranteed to be flat within a few ten thousandths of an inch. Then place a large piece of very coarse sandpaper, 40 or 60 grit on the plate and grind away with the blade in the plane but retracted so it won't be damaged. Once you get the sole flattened, then switch to finer grades of paper to polish it up.

   A good simple way to protect from rust is to rub ordinary furniture wax on the exposed surfaces.

   John White

2. 
   sirprize21 | Oct 14, 2008 05:22am | #2

   http://www.taunton.com/finewoodworking/ToolGuide/ToolGuideArticle.aspx?id=29712