Originally Posted by
mic-d
What I think is happening to cause the troubles with the scraped plane is your years of experience of hand planing and your muscle memory. It's linked to the parts of the quote I included above which you outline what has to be overcome by a novice.
What I think is happening is you're unknowingly taking a lighter shaving through the middle and a heavier shaving at the end. This is not to do with the weight of the plane and not to do with any error in your technique per se, but just that it needs tweaking for the new planes, as Ian and I suggested earlier.
I would try using a little less pressure on the toe to start, more pressure evenly through the middle and a little less on the heel/none on the toe at the end. All other things being equal (managing deformation etc as you mentioned in your reply), geometrically, there is no explanation for your difficulty coming onto and going off the work with a scraped plane other than pressure changes changing the thickness of the shaving. There is no reason the plane cannot begin with a 0.00x" shaving, maintain that through the middle and maintain it practically to the end*.
Well there it is, my explanation of what's happening based on the fact that a blade registered to the work by a dead flat sole simply can't take an uneven shaving by some geometric function of the arrangement and only by the accidental innapropriate force throughout the pass from legacy muscle memory. So it's just a matter of tweaking long learned memory. Can you offer a different explanation related the the sole/blade arrangment?
*[I say practically because as I mentioned in my reply to Martin, the plane is kept registered perfectly uniformly right until the point the front of the mouth slips off the work. The blade is maybe 1/50" from the end if you have a close mouth. Then, theoretically because there is a gap at the back of the mouth the thickness of a shaving, the heel will settle onto the work and bed the blade in up to one shaving thickness further into the wood. Practically there won't be a gap behind the mouth, just a lower pressure of the sole right behind the mouth, and as the front of the mouth slips off the work, pressure comes onto the sole behind the mouth, but you obviously don't hear a 'clunk' as the sole slaps down:wink:. This snipe of a small amount extra at the end is not possible overcome, it's part of the nature of the plane with a flat rather than stepped sole as on an electric plane/jointer. So the snipe on the first pass is maybe 1/50" from the end and maybe a shaving thick. With each extra pass it may move back 1/50", so it's meaningless in practical terms as causing the problem you have.]