Who else uses a scythe?

The arc of a stroke is comprised of two things: the path and presentation. It's as if the scythe were mounted on a lazy Susan on top of a rail road cart, with the track being the path and the presentation being how the scythe is oriented (by pivoting the lazy Susan) relative to that path. In the above image, the red circle (partially visible) represents the minimum radius of a stroke, in which the right hand is the pivot and no motion along a path is made. The curve of the edge is set equal to that arc, and so at that stroke the blade would be in 100% slicing action, and so technically wouldn't cut anything, but instead skirt perfectly around the target. The two green circles (partially visible) represent radii centered on the left hand and extended to the toe and heel of the blade, which describes the depth of the swath, but you can see that increasing the radius of the stroke has, without at all changing the hang of the blade on the snath, closed the presentation to the stroke, causing the angle of the toe relative to the stroke's radius to become greater than 90° (the fuchsia angle) and therefore the spine is leading instead of the edge. The blade will not cut, then, until the blade's presentation is brought to an angle of 90° or less relative to the stroke.

Regardless of the shape of the path, this rule must be obeyed, or the spine will precede the edge in the stroke.
 
With the hang opened to bring it square to the radius. 16.2° of rotation, with a minimum fully-engaged swath depth of about 4"

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I've been kept too busy to mow recently, but finally squeezed in some time to take care of the neglected area behind the house. :)

A mix of grasses, weeds, and clover, all knotted together with vetch, flattened and laying in every direction. It's a bit more of a technical challenge to tackle than nice standing vegetation!

[video=youtube;bCGE16f2rkk]https://www.youtube.com/watch?v=bCGE16f2rkk&feature=youtu.be[/video]
 
FortyTwoBlades said:
...The required presentation of the blade's arc relative to the radius of the stroke. You can see that in this case the angle is greater than 90°, and so the edge is trailing rather than leading like it should.

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Click to expand...

FortyTwoBlades said:
...causing the angle of the toe relative to the stroke's radius to become greater than 90° (the fuchsia angle) and therefore the spine is leading instead of the edge. The blade will not cut, then, until the blade's presentation is brought to an angle of 90° or less relative to the stroke.

Regardless of the shape of the path, this rule must be obeyed, or the spine will precede the edge in the stroke.
Click to expand...


I think that if you set up your blade as pictured above, you could readily find a "shape of the path" that would enable the blade to cut, despite the "rule" that "must be obeyed".

A purely circular stroke seems oversimplified. In plain terms, there can also be a "side to side" component and a "front to back" component of the blade's motion.
 
Steve Tall said:
I think that if you set up your blade as pictured above, you could readily find a "shape of the path" that would enable the blade to cut, despite the "rule" that "must be obeyed".

A purely circular stroke seems oversimplified. In plain terms, there can also be a "side to side" component and a "front to back" component of the blade's motion.
Click to expand...

I don't think you understood my statement. You're talking about the path of the stroke, which may impact the presentation of the blade. In these diagrams the circles are the paths, and the rules follow for other path shapes--not just purely circular ones. If the presentation of the blade relative to the path is made any more closed, the spine leads the edge and so no cut is made. If the presentation is equal to or more open than square, the blade will cut. A purely front-to-back motion would be as open a presentation to the path of the stroke as possible. Purely side to side is similar to an arced path, but deeper. And again, these circular pivots shown here are only one component of the total stroke but they represent some of the most essential ones as they are occurring at the very end of the pivoting linkage. I'm not even close to done with these diagrams, and a complete linkage will be a part of its culmination, but these pivots illustrate some fundamental principles that you have to understand in order for the rest of it to make sense. These are minimum and maximum pivots on the snath and their effects on required blade presentation for full engagement. Regardless of the shape of the path, you cannot close the presentation of the blade relative to the path without causing the edge to trail instead of lead, and you cannot open it any further without increasing the minimum depth of the stroke for full edge engagement.
 
It would be interesting to have a friend film you with a drone straight above your head. You could then map out the actual motion of the scythe. It might give you further insights about your hangs.
 
I can map it out pretty easily and have already done some work using scribes in the dirt. The actual stroke fairly closely resembles the beginning of a phi spiral. However, the actual shape of the stroke has little impact on what I'm working on describing at the moment, so it's of minimal concern for now. I'll be addressing matters pertaining to a complete stroke as I finish up my diagrams, but I'm focusing on the most fundamental principles at the moment.
 
John A. Larsen said:
FortyTwoBlades, where did you get the French Colonial Pith helmet? John
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I got it here. Had it for something like 3-4 years now and it's the real deal. Holds water like a sponge and keeps you cool through evaporation. The helmet-style suspension keeps air flow good around your head. Smells like rubber cement for the first 3-4 times you soak it, but disappears after that. The "chin strap" is decorative and made of cheap pleather with non-functional press-formed "buckles", and I removed it right away. It's only held on by one little brad on each side. A real nice piece of gear for practical hot weather wear, and I'm seriously surprised that they ever fell into disuse.

Some more in-progress images, while I'm at it. Again, these aren't finalized diagrams, but shows some progress on what I'm working on while demonstrating the matter of presentation vs. path in a stroke. The red line denotes the path, with perpendiculars marked at intervals. The heel is locked to the path in all instances.

Figure 1: blade orientation held static as it traverses the path. Note the angle shifts relative to the path that result (the orange line crossing the red one at the toe of the blade.)

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Figure 2: The toe of the blade is brought square with the perpendicular markers at each interval. Note the change in swath depth that occurs. If the position of the toe were brought lower in any of these instances, it would cause the edge at the toe (or more) to be trailing rather than cutting, as well as shielding the region behind it. These represent the minimum presentations for full edge engagement.

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Figure 3: The depth of the swath is held constant. This is roughly the minimum swath depth that can be held along this particular (unusual) path with full edge engagement, as determined by the maximum required openness of the presentation established in Figure 2.

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[video=youtube;9_SozAN6aOs]https://www.youtube.com/watch?v=9_SozAN6aOs&feature=youtu.be[/video]
 
Same. Even this li'l thing wasn't cheap, but with the volume of blades I do this with, it's been worth it. Just not having to futz about with an open flame, alone, makes this this machine worth its weight in gold. You can't see it, but out of frame there's a ton of ash shavings (which I'm cleaning up tomorrow) that I was able to work around without having to worry too much about setting on fire. :D
 
Was doing a little mowing yesterday and snagged a hidden steel fence wire, which completely folded over most of my edge (only about 2.5" at either end was spared) and it provided a good opportunity to see how the bond strength of the Arctic Fox scythe stones would hold up, since that kind of folded edge will often scrape or gouge up softer stones. Surprisingly, not only did it iron things back out, but it actually was able to fully restore my edge to nearly the condition it was in before the mishap after only two passes! For how fine of an edge it imparts I was kind of shocked at how little time it took to get the blade back in action. I figured the most I'd be able to do was maybe cut off the roll, but that I'd have to bust out one of the coarse stones to get it mowing again. Obviously I'm biased, but I'm loving the heck out of this thing. Wish I'd taken some "before" pictures, but by the time I thought of it it was too late. :p

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At one point in time, Seymour used to put these cool little domed caps on their nibs, which gave their top a rounded shape and also just looked pretty nifty. I managed to track down a source for some similar ones. :D

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Found this interesting portrait of Silas Lamson. Note that the snath he's holding appears to be square in cross section and the nibs lack bands. I suspect this was painted pre-1840.

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My cynical view on square cross-section when found in old woodwork is that it is a sign of quality, since at the time it was actually harder to achieve than these days! That was long before "ergonomics" became a buzzword also :).
 
I'd argue against it being harder to achieve in this case. Pretty easy to get things flattened out with a spokeshave and/or rasps. And easy to shape down from a riven blank, which is what most snaths were formed from. Then it's just a matter of sanding/rasping out any delaminations from bending and establishing either a uniform surface or smooth taper. The nibs, lacking bands, would not be adjustable in this case unless there was a series of holes, and rotation around the snath wouldn't be possible. There does appear to be a rod still through it to affix the nibs in position. Normal nibs of the time would have been a loop and tang that was wedged to affix it in position, so this snath is unusual.
 
Any coupon codes for baryonyx? I'm almost done with the $20 scythe restore and I want to get a stone to finish the edge the rest of the way
 
We follow the "everyday low prices" model, and so don't run sales/specials. Instead we just price stuff as affordably as we can so every day is the best day to buy. :)
 
Awesome I'll pick one up in short order, also, I'm looking for the vid 'sharpening with scythe stone- scythe.'
Did you make that one? I'm not seeing it. Subcribed btw ;)
 
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