The Significance of Knife Marks on Lumber Core Surfaces

Many woodworkers have been puzzled by the fact that, where a seemingly perfect job of planing has been obtained on veneer cores, with no knife marks showing, the glue room nevertheless does not obtain as good an adhesive bond as it often does with lumber-core stock with rather pronounced knife marks on the surfaces. The reason is that material that has been dressed with knives jointed rather heavily is subjected to an ironing-out effect. That is, these knife-edge heels “iron down” what would otherwise be the ridges between knife marks. In doing this the heels behind the knife edges really compress the ridges. Such compression closes the pores in the wood and glue cannot penetrate effectively. The problem may be solved by planing with knives that have not been jointed whenever lumber cores are being processed.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member