Joel
>I've scraped to sruface plates by fair share of planes and I've even given a course in scraping planes a long time ago. It has the advantage that it's easy to do, the equipment is minimal, and you can scrape to whatever accuracy you wish.
The problem I have with lapping is that it's easy to go convex from side to side and with longer planes it is a lot of careful work.

A few years ago I discovered that if I use a bit of wet or dray sandpaper in a hard sanding block I could trivially flatten the high spots in a lot less time. To check accuracy I use a straightedge. THe method is very easy, requires no special equipment, is very fast and while not as accurate as scraping to a surface plate it's more than adaquate for planes - and if you want even more accuracy you can scrap or lap the last bit to finish up