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David farmer
09-26-2016, 6:13 PM
My search turned up a 7! page thread on the origins of the coffin shape so I figure this must be the place for plane design theory.

I'm referring to the plan view of the sole. Are they often D shaped to protect a vulnerable corner of the plane, Reduce the chance of marring the work, some dynamic of planing, or just for aesthetics?



And a related question. I've seen a bevel put on Japanese style planes from the outside edge to the mouth opening. wouldn't this promote chips getting under the sole instead of being pushed aside?
If it serves an important function why is it not seen on metal or western wood planes?

Any thoughts welcome.
Thanks.

Stanley Covington
09-27-2016, 11:42 PM
My search turned up a 7! page thread on the origins of the coffin shape so I figure this must be the place for plane design theory.

I'm referring to the plan view of the sole. Are they often D shaped to protect a vulnerable corner of the plane, Reduce the chance of marring the work, some dynamic of planing, or just for aesthetics?



And a related question. I've seen a bevel put on Japanese style planes from the outside edge to the mouth opening. wouldn't this promote chips getting under the sole instead of being pushed aside?
If it serves an important function why is it not seen on metal or western wood planes?

Any thoughts welcome.
Thanks.

David:

In response to your question about Japanese planes, it is standard to have a slight bevel at the side edges of the sole. I think this is indeed common on Western wooden-bodied planes as well. They protect the sole from dings and chipping. It also gives the fingers a little better purchase on the plane when lifting it. It feels and looks right. It really doesn't seem to increase the amount of shavings that find their way between sole and work surface.

But you bring up a valid point. In light of the direction the plane is being moved when cutting, a bevel at the sides or back of the plane makes no difference, but a bevel at the leading edge of the plane does dramatically increase the amount of shavings that get under the sole. This is a rookie mistake, but quite common.

Getting back to your question, some people exaggerate the bevels at the side cutting them all the way to the mouth, as you pointed put. This provides for an even better grip on the plane's body, and indeed feels very comfortable. In addition, some people believe that connecting these bevels with the mouth allows plane shavings stuck in the mouth's corners to protrude, kind of like a moustache, I suppose, without getting stuck underneath the sole and messing up the plane's accuracy. The comfortable factor is a matter of personal preference, I suppose, but the moustache theory is simply a sign that the person who setup the plane doesn't know how to use his plane properly and/or maintain the blade properly. Despite some of the advice of published individuals that promote such nonsense, you should avoid such obvious signs of amateur status.

But what harm is done by cutting the bevels a bit larger, you ask? Make yourself a little cross-sectional drawing of the plane's mouth right where the blade sits. Notice how little wood actually remains at this location. Then consider the stresses on that section of wood as you push and pull and press down on the plane. Also consider how that wood must resist the deflection those forces exert on those little sections of wood.

Next, calculate the area of wood that remains at this thinnest area. Then draw in a big bevel at each side, all the way to the mouth, and calculate the cross-sectional area of these bevels, and calculate the percentage of material lost due to these bevels at this critical area. I think you will find that it is a significant percentage.

So you can see that cutting large bevels all the way to the plane's mouth significantly weakens the plane, and increases the amount of deflection thereby decreasing its accuracy, while decreasing the useful life of the plane's body as the sole wears quicker with use (remember that the total area of the sole's bearing surface is also reduced as the bevels increase in size). And all this for a more comfortable grip on the plane? Or to compensate for a lack of common skill in using the plane? Not a good tradeoff in my opinion. And so embarrassing if others see it...

Stan

David farmer
09-28-2016, 11:16 AM
Thanks for your reply Stan.
You brought up a couple of things that relate to the reason I posted.

I seem to always be on a search for a small one handed plane that has a collection of features I can't find on one plane. As a result, I find myself frequently modifying existing planes in an effort to create what I'm looking for. Especially regarding grip. I accidentally stumbled on the benefits of the corner bevel on Japanese planes and am considering putting it on a number of my metal block planes.
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I put this long shallow bevel on this plane in order to reach into the corner when rounding braces on musical instruments.
A side effect was a much better feeling of grip security when lifting the plane.
Unfortunately, the bevel down design of this little guy, forces futzing with back bevels to control tear out.

The comfortable grip on my 60 1/2 block plane is the gold standard for me. I don't understand why LV and LN have ignored the benefits of Stanley's oval side indentations.
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I'm forever trying to duplicate the comfort of this grip on other one handed planes.
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I've even ground indentations on a few which help quite a bit but the plane in the above picture has a 1 5/8 blade that is just too wide for me despite having large hands.

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The LV apron plane is the worst. I am baffled this plane made it into production in this form. It feels like an absolute soap bar to me. To say nothing of the sharp corners on the sole that seem poised to do damage.
There is a lot of real-estate between the edge of the blade and the corner of the side and sole.
I asked about the Japanese bevel because I'm hoping to transform the feel of this plane by putting a shallow, Japanese type, bevel on it.

I also wondered about the shape of the plan ends because when I make a plane shorter, I have cut them square and round and don't see any difference. It made me wonder how the rounded shape came to be and if there was a purpose I was not aware of.

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My LN #102 has sides that flare out a bit but still feel slick and not nearly as secure as the indentations on the 60 1/2.

I'm still dreaming of my perfect block plane.