Y’know, that’s actually a pretty good question.
With a ‘stock’ power planer, changing the depth setting on the fly while cutting is pretty much precisely what you don’t want to do, being as they’re made to make wooden things flat. Very, very flat, as flat as they can be made.
Cutting foam is a whole 'nother story. The dust from it ( not shavings, especially not wet sticky oak shavings) isn’t the same issue. You can pretty much cut all the thing will do.
Controlling depth of cut - that’s kinda interesting. If I was going from a blank slate, I’d have to think a while.
See, you are gonna hold the back handle/trigger with your strong hand. Your right, if you’re right-handed and your left if you’re not. Your other hand is up front, on a knob or something. It’s not the one you have the best control with.
So, maybe the controls should be mostly if not all in the rear handle. Say, power on/off done with either a trigger or a thumb button and the depth adjustment with the other one. That lets the front hand - the one you’re less coordinated with, all that has to do is hang into the front and steer. Rather than the strong hand doing little but holding a trigger while the weak one controlling something fairly fine and fairly difficult to do right.
There’s a technical issue here. If the control is too easy to operate, that means the spring the depth-gizmo is operating against is has to be kinda weak. And that in turn means the front ‘shoe’ is gonna tend to bump up and down on its own rather than staying under control.
Also, should the depth adjustment be direct, kinda like picking up or lowering down a thing on a stick. Or should it be the spiral ramp deal that it is on some of the better planes. Or a cam, like it is on my favorite, the Rockwell 653? All of them have good points and bad.
Certain ease of machining issues - the Hitachi screw thread setup is dumb easy, it’s also used on most cheap planers. The spiral ramp isn’t too bad either. The cam is a beeyotch, it kinda needs either good machining or really good casting.
But something else occurred to me - these things don’t have to be all metal, which requires casting, forging, machining, etc. It could be made , at least in part, from wood. At least the working models.
So, gentlemen…and any ladies that may want to play ‘design-a-tool’ - start your saws, planes, chisels and what have ya…
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