Originally Posted by
Patrick Chase
Camber (the constant-radius kind as in the blades I posted in the other thread) is the key here. 15-20 mils is child's play with a r=6" blade, though of course the shavings are fairly narrow (1" wide at 15 mil cut depth, 1-1/8" wide at 20). Also cross/diagonal strokes are easier than lengthwise at those depths.
Steve, what blade profile are you using for that cut depth?
If you're crazy enough to rough with a flat blade or one with "turned-up corners" then yes, 15-20 mils will be rough going. It's doable and I've done it, but not my idea of fun.
EDIT: If you're using a scrub with a lot of camber then 15-20 mils is even easier. The resulting cut widths are 0.7" and 0.8" at 15 and 20 mil projection, respectively.
Hi Patrick,
Your numbers seemed off to me, so I ran them myself…for a 6" radius, I get:
.021" at 1" width of cut
.027" at 1 1/8" width of cut.
Can you doublecheck please? One of us is off; it could certainly be me.
Anyway, to answer your question, I use a 10" radius on jack planes. I never used to measure, but I kinda have to now.
If my calculations are correct, I get .013" at 1" wide, .016" at 1 1/8" wide, and .020" at 1 1/4" wide. that seems right to me. Just eyeballing, I'd say that 1 1/2" wide cut (with a 2" iron) is the absolute max for me in hardwood, and it's usually less. For David's example of hard maple, the 1" width would be plenty. For something like EWP though, I could take almost full width shavings.
"For me, chairs and chairmaking are a means to an end. My real goal is to spend my days in a quiet, dustless shop doing hand work on an object that is beautiful, useful and fun to make." --Peter Galbert