Friday, May 11, 2012

Q&A: The Balance of a Scythe


A wildwood snath (made by Peter Vido from alder wood) is suspended 
by the right grip. Note the thicker upper section of the snath.


Dear Peter Vido,  
 
I was hoping you would be able to elaborate on your suggestion that the scythe be balanced along the length of the whole tool, even going so far as to suggest adding extra weight near the upper (handle) end for some models !  

An argument can be made the scythe should be bottom heavy (at the blade end). First, such a scythe would always weigh less, a good thing. Second, the tool would then be analogous to swinging a ball at the end of a rope, with great centripetal force.
 
Of course, such an unbalanced system would increase the friction between the ground and the blade making the mowing of hay (for example) harder. But some people suggest pressing the blade down on the ground when cutting a grass lawn, and a bottom heavy scythe would require less pressing.

So, does it depend on what the terrain is? on what you are cutting? etc.?

Best wishes and thank you.


Your question is logical; you are obviously considering the physics of it all. And perhaps many of the designers of the traditional snaths thought along the same lines. Were they "wrong"? Who is to say? But we all know that many traditional tools could have been designed better.

You also already know (by reading my take on the issue) that I would not want to use those heavy-nosed snaths. Not now, since I've stumbled upon what I consider a better design. And I do mean stumbled -- because I did not approach the matter as an engineer, but as a farmer guided by 'feel' rather than an understanding of physics. (I had once described the 'story' of how it happened, but perhaps it did not quite make it into electronic form...)

I presently can't take time for a long discussion on this topic, so let me get away with just jotting down a few points:

1.  Of all snath designs, the one which mostly benefits from some counterbalance for the weight of the blade, is the one with two grips pointing towards the mower. In addition, with the style of movement I advocate, the "light-at-the-bottom" unit will be most appreciated. By "light-at the bottom" I mean that a snath without 
the blade will more or less hang/lay horizontally if suspended upon a finger from the lower grip. Once the blade is mounted the unit will, of course, be heavier at the bottom.

2.  The downward pressure upon a blade during its cutting stroke is a good (sometimes even necessary) technique under many (though not all) conditions. I did not "invent" the idea, but yes, I was probably the first to present it in print -- at least in the English language. However, if you wanted to make a snath whose bottom end weight would "automatically" fulfill the function of the downward pressure, you'd end up with an awfully heavy and awkward tool overall. Keep in mind that at least half the time the scythe is used, it is not actually cutting (the backstroke already represents a half...) During all that time, a unit that feels like a well-balanced 'feather' in your hands is a pleasure to use, period. 

3.  I should also note here that for the single-grip snaths (which are held mostly at a more upright angle), there is NO advantage to have the upper end heavier; in fact it would be counterproductive (I've tried this as well).

To sum up:
Try your physics in the field; if you come up with anything revelatory, please get back to us.

With best regards,
Peter








3 comments:

  1. From the same person who asked the question Jeffrey H. Adams.

    Thank to Peter Vido for his deep insights and comments.

    Perhaps a "balanced" snath may be preferred is as follows:

    When the scythe is fairly bottom heavy, the work load of using the scythe falls more on the right arm and hand(for a right handed person). A balanced scythe lets the work load be more shared between the 2 arms and hands. Furthermore, a fairly bottom heavy scythe puts the body in a kind of imbalance towards the side where the blade happens to be at the time. When the weight (bottom heavy part of snath) is on your right hand side it will exert strong leverage against your body on that right side. A more balanced scythe reduces that leverage.

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    Replies
    1. @Jeffery Adams: I'm not sure I completely understand you here but I don't think I agree. When I mow (as a right handed person) I use more force with my left arm on the cut stroke pulling the scythe and my right arm pulls some/gives down pressure/steers/balances the blade. On the return stroke my right arm lifts the scythe and both arms return it to start position. My arms do not feel unequally stressed at the end of mowing.

      I have done extensive experimentation with this aspect of balance in the past and discussed it with Peter at some length. My approach differed with Peter's in that instead of tapering the snath from blade to left hand like the one in the picture, I put a downward pointing stem 6"-18" in length near the left handle and attached a piece of wood for a weight. This not only gave the tool good overall balance it lowered the center of gravity which greatly stabilized the horizontal balance of the blade. Additionally if my attached counterweight was offset I could rotate in a way that changed the overall horizontal balance of the blade, giving tip weight or giving tang weight depending on the rotation. One drawback is depending on how the counterweight is attached it can make field dressing (stoning) awkward. The reason I've discontinued this design element is that IMO if you really do a lot of mowing the overall weight of the tool is more important than overall tool balance and ease of use. IMO, horizontal balance of the blade is more important than overall tool balance. Peter will probably agree with me here. See his article on long blades and various other gems on scytheconnection.com.

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