ok, so i'm fairly new to woodworking, so this maybe a really dumb question, but i was hand planing a board the other day and i first planed across the grain (across the width) and got it pretty flat, and then when i planed it across the length for some reason it always ended up tapering down at the far end... like the part of the board from where i started the stroke was an 1 and 1/8 and the far end was slightly under an inch... what am i doing wrong? if i turn the board around the plane from the opposite end i get tear out... i'm using a not so great plane a "groz" #4, but i tuned it up fairly well i think... the iron is pretty sharp and all that... but i just don't know how this is happening... thanks... jonny