Helical vs Spiral vs Straight Knife Planers

[Jimmy Harris]

Sending the board through the planer in the proper direction is far more important that feed speed. Feed speed is just about cuts per inch for a smoother look, but it does little to change tear out, Does your hand plane, going the wrong way, produce a better cut when going slow?

No. But the hand plane does produce a better surface when taking a shallower cut. That's the thing with adjustable feed speed. Usually, the cutter head speed is constant. So, at 1/2 feed speed, you're taking half sized bites across the horizontal plane with every pass. A thickness planer doesn't work exactly like a hand plane. It takes out little scoops instead of long shavings. But both tools tend to make smoother cuts when taking smaller bites, because the wood you're removing is more weakly connected to the wood in front of the blade. So, it's less likely to pull it up with the section of wood your blade is engaged with, and tear it out.

Slower feed speeds are especially handy on boards with reversing or figured grain, where no matter which direction you feed the board, some of it is going to be against the grain. That, combined with a shallower cut, can really help a lot on potentially problematic wood.

But yeah, feeding in the proper direction is definitely far more important than feed speed. I'd even argue that depth of cut is more important as well. A slower feed speed is just another arrow in the quiver to deploy, should you need it.

[Warren Lake]

I barely look at grain, maybe edges maybe not. directions changes in many boards, put the board through and it will tell you. Feed rate is most important I can run birdesye one pass one shot slow feed rate and its clean. Thats why I kick my SCM in and out of great to slow the feed rate down till I get a gear motor. I dont care about the formulas and do this or that, You build a piece of furniture and you want clean you are not running 1000 feet for a piece of furniture.

My general could cut almost as clean as the SCM because the feed rate was 25 percent slower than the SCM.

[Michael Schuch]

Michael was this a floor model with sharpenable blades? 10 years is a very good run for a blade set. Benchtops have very thin blades most of which are not capable of being sharpened

Yes, floor model with sharpenable blades. They needed to be replaced many years before I did. I finally ran out of area that had usable blade. If I had know it was so easy to replace I would have replaced them a very long time ago! I do have a blade setting fixture which made the height easy to set.

It would be nice to have a helix insert type head... but I doubt I will ever get one since my straight knife planer does such a nice job.