Posted by David Sherman on Monday, April 23, 2007 at 23:28:32 :
In Reply to: Re: o.t. wood planer question posted by jim in n.y. on Monday, April 23, 2007 at 20:05:35 :
Search the site for "spiral" or "helical". Two articles I found that might help you were:
http://www.woodweb.com/knowledge_base/Purchasing_a_Helical_Planer.html
http://www.woodweb.com/knowledge_base/Helical_cutterheads.html
The consensus seems to be that helical reduces tear-out on highly-figured wood, but on easier wood it does not produce as good a finish as straight knives in general and straight steel knives in particular, if you're willing to put the effort and skill into grinding and jointing the steel knives frequently. They say that helical requires more sanding, which kind of surprised me, but apparently the discrete cutters do leave small ridges. On tough or figured wood, that's still better than tear-out, though.
I think if I was buying a nice new 20" shop planer, I'd budget for both heads, since it sounds like each has its definite advantages.
Follow Ups: