Replies

1. 
   RalphBarker | Feb 07, 2013 06:40pm | #1

   Conflicting Advice

   Conflicting advice? Welcome to [ insert name of favorite passtime here ].  ;-)

   It seems to me that the concept of cambering a plane iron, even if just ever so slightly, would apply whether one is an "upper" or a "downer". (Which, of course, is entirely different than being an "innie" or an "outie".)

   Most "sources" suggest that the amount of camber should vary from significant (1/8" or more for a scrub plane) to very slight (perhaps 1/64" for a smoother), with a jack falling somewhere in between. The idea is to remove wood without leaving a torn, hagged edge, as would be caused by a sharp corner.

   For some uses, however, a camber is not desireable. This would generally be true of an iron used in a plane on a shooting board. You want the edge of the board to be straight and square, And, since the corners of the blade don't touch the surface being planed, no camber is needed. The same would hold true for a block plane used for chamfering edges.

   The trick is to simply have different irons with differing amounts of camber, depending on the task the plane is performing at any point in time.

2. 
   Metod | Feb 08, 2013 08:46am | #2

   Amount of Cambering

   depends on the angle that the flat  (back) of the iron forms with the sole of the plane. For a  bevel up that would be as low as 12*, bevel down would range from ypically 45* - 55* or even higher.

   For the same amount of protrusion, the lower the angle, the more pronounced the 'curving' (camber) has to be. You could calculate the amount of cmber for a desired amount of protrusion depending on the angle. A smidgen of trigonometry does it.

   I do not use camber on my shoulder planes or block planes. The surfaces where I use block planes a usually narrower than the irons, so the ridges are not an issue.

   Best wishes,

   Metod