Many thanks to all for your contributions. My apologies for this late response. I spent over 45 minutes last night reading all the responses to date and typing my reply only to find that when I tried submitting it, it crashed and told me to contact the site manager or something similar. Better luck this time.
I should perhaps have made it clear in my original post that I do very little work with hand tools preferring to use machinery for planing, sawing and the like. In fact, I only own two planes – a Woodriver block plane that I bought from Peter Sefton’s shop last year and a Stanley No 4 that I bought back in 1970. I had previously sharpened the cutting iron on the No 4 and had a go at flattening the sole using an Axminster diamond stone.
The reason for my original question was that, although I could see that a granite plate would be fine from the rigidity point of view, sticking a piece of coarse abrasive on it would not seem to help with the flatness. I measured the thickness on both a belt from my belt sander and a piece cut from a roll. Both were over 1 mm thick and I wondered whether, in pressing down on them, even on a hard flat surface, would compress the paper by a few thou thus rendering the flatness of the plate immaterial. As such, I thought that wet and dry would be a better bet if “stuck” down with water. This is what Jacob and others seem to recommend although there seems to be a debate as to whether to use water or white spirit. Of course others maintain that ordinary abrasives stuck down with adhesive are just as satisfactory as wet and dry.
There also seems to be some debate about whether you can use MDF, properly braced, to get the sole “flat enough”. There also seems to be some disagreement as to whether an old glass shelf is flat enough for the purpose.
Ignoring the pros and con of the various methods, I’ll probably go for the easiest and cheapest solution. I have a workbench with a top made of 38 mm kitchen worktop covered by a sheet of 12 mm MDF. I’ll probably get a smallish piece of melamine faced MDF as Graham suggested, check that for flatness using my Veritas straight edge, and use that with some wet and dry to see how I get on.
My thanks go to Matthew at WH for his suggestion about using printer paper in lieu of a feeler gauge (which I used to have but haven’t seen in a long time since cars got too complicated for me to work on after about 1985 since when I have only owned diesel cars). One thing about the paper technique I wasn’t too sure about was, if you can’t get the paper under the rim, how do you know that the base isn’t concave near the mouth? Presumably by using the straight edge.
One final thing, before I leave Jacob and D_W to continue their debate, is that I noticed that Paul Sellers makes the point that you should keep the blade and cap iron in place when flattening the sole whereas Chris Schwartz stripped the plane down. My gut feeling is to go with Paul on this.
Once again, many thanks to all; 35 posts in just 24 hours!
P.S. If all else fails, I’ll just have to buy a new plane but that may be the subject of another post next year.
Martin
