Wondering something about hand plane design

[Tetsuaiga]

I was wondering when we design stationary planing machines, there is an infeed and outfeed table. The idea is that the outfeed is equal to the rotating cutting blade height and the infeed height controls how much material is cut away.

If you were to design a hand plane with differing sole heights the same as a stationary planer would it work any better?

I imagine the answer might just be that if there were any advantage, then its benefit wouldn't outweigh the extra difficulty in manufacturing a hand plane like this, especially when the user can correct any less than perfect planing action as they go about their work.

Does anyone have any thoughts on this?

 

[Bm101]

I don't understand the question tbh. Sorry. (Justa beginner here but I wonder what you mean?) On a planer the wood is kept bedded as it goes over the rollers and the blades no? With a hand plane you are are controlling the effect of the plane and the blade. What you lose in mechanical advantage you gain in control? The way I imagine it is a a machine cuts to an average.
I can't even get my brain round the concept of a hand plane with differing soles. I'm not being a naysayer in any respect! Can you explain more what you mean? I might be being dense, sorry.

 

[Limey Lurker]

I have, many times, considered this, and the conclusion I have come to is that it would be excellent if the plane blade is wider than the work piece, but it would be very difficult to attain a wider flat surface, as anyone who has ever tried to use a hand electric plane to flatten a workpiece wider than the blade will know. Possibly a very slight, shallow blade camber would make it easier.

 

[Terry - Somerset]

I assume this would need a mechanism to move the front of the plane (in feed) up and down to vary the depth of cut. The amount of precision machining required for accuracy, square and precision may be fairly complex. It would anyway not obviate the need to have a removable adjustable blade to allow sharpening and resetting.

 

[RossJarvis]

It's something I've thought about as it's precisely how an electric hand plane wotsit works. You'd think that the rear of the sole would come in slightly higher than the cut surface and slightly cant.

My conclusion is that it would probably be too costly to make and because they've never done it it doesn't matter.

 

[monkeybiter]

It would be easy to try; temporarily stick a large shim on the sole to the rear of the blade, set the blade protrusion to match the shim and see what happens.

 

[novocaine]

is it not more to do with that fact you are taking smaller amounts with a handplane so the bed/sole isn't as much of a contributing factor? I'd have thought it matters more as the cut size increases and the piece needs more support.

the stanley 75 and 90 bullnose planes have a higher nose than sole, but it's still a nasty plane to use. (not really)

 

[Jacob]

It'd work if the workpiece and the plane were very firmly held and the plane fixed to a track. Which is more or less what you get with a planer/thicknesser.
Otherwise the slightest lift in the cut would be followed by the sole, producing more lift out of the cut . Which is more or less what you get with a hand held power planer and is why they are a PITA.
In fact a hand plane (powered or not) cuts a scoop; it dips in and rises out of the workpiece. Long or short scoop depends on how firmly held. Cross section of scoop depends on blade shape. Hence shallow camber preferred for finishing as the cut needs to taper to zero at the edges and be not too deep in the middle.
Shine a torch over any hand planed surface and you will see the scoops - neat and regular if done carefully with skill, all over the place if not.
Imagine levelling the surface of a tub of ice cream with a spoon - the pattern would be very similar. The shallower the scoop the nearer you approach flat, without ever quite getting there.

 

[Tetsuaiga]

Interesting responses. I didn't know the electric ones were built like that, the tracking phenomena does sound like it could make things difficult. Jacobs point about any lift in cut and the after effect is a bit harder for me to understand, but guess it makes sense.

I suppose it would actually be quite easy to try if you just stuck a bit of wood on, trim it flush and match the blade to the rear.

Bm, hopefully the other responses helped you get an idea what you I was getting at. If not just try and find any diagram of a surface planing machine, then flip it upsided down and pretends its a hand plane.

 

[woodbrains]

Hello,

No, it wouldn't work and I do believe it has been tried. I recall seeing a picture of a hand plane in a book many years ago which did just as you suggest. It may have even been patented.

The hand plane works precisely because the infeed and outfeed soles are a single plane. Wood is a lot more compliant than you would think, and there is a necessary increase in downward pressure when the shaving is lifted. Wood tears terribly when the pressure is absent and a fine mouthed plane reduces tearout precisely by utilising the pressure increase to hold down the shaving and prevent splits propagating ahead of it. IIRC the plane I refer to above failed because of this.

Mike.