Planer Blade ?

[L. D. Jeffries]

Sitting around my friends shop this PM having a beer break when one of the gang asked the following question. "Have you ever heard about sharpening planer blades differently for use on hardwood?" We all did some head scratching on that one; but I do seem to remember reading or seeing somewhere about having your sharpening service put a "negative" hook on planer blades to use on exotic wood, or wood that is subject to getting little (for the lack of a better word) digs. The "negative" hook may not be what it really was, but can't for the life of me remember the exact terminology that was used. Told the gang I would get on the BT3 forum, as someone out there probably would know what we were talking about. You guys have yet to fail me so far.

[drumpriest]

Back bevelling is one thing that you can have done, it significantly reduces tearout with curly materials.

[Slik Geek]

"Have you ever heard about sharpening planer blades differently for use on hardwood?" We all did some head scratching on that one; but I do seem to remember reading or seeing somewhere about having your sharpening service put a "negative" hook on planer blades to use on exotic wood, or wood that is subject to getting little (for the lack of a better word) digs.

Perhaps you guys were recalling Fine Woodworking magazine, November 1985. "Jointer Talk" by Jim Cummins.
"Most jointers are designed to handle both hardwoods and softwoods and have a rake angle of about 30 degrees. For softwoods, such an angle works fine, but it's too acute for may hardwoods - when you cut against the grain, the wood splits ahead of the cut, chipping and tearing the surface. Hardwoods are best worked with a steeper rake angle, in the range of 10 degrees to 20 degrees. This more scraping cut leaves a smooth surface."

He goes on to suggest back-beveling (or face-beveling) each knife to achieve the lower rake angle. This article was reproduced in "The Best of Fine Woodworking".

PS - Never experimented with this myself.

[L. D. Jeffries]

Thanks "drumpriest" and "Slick Geek". Knew someone would have the answer. Since I surface a lot of hardwood guess it would be a good idea to have one set of blades put aside just for that. Thanks again gang.