USDA/Forest Service Sharpening gauge

[transmaster]

I just did a LOT of thinking today about this and I hit on a very simple arrangement that should work very nicely on low angles, but I have to do MATH™ to optimize it because even though the current setup works the readout would be very small and I want something pocket-friendly that remains readable.

Let us know what you come up with. Perhaps you could pair this device with a smartphone app, that would take care of the display issue.

 

[FortyTwoBlades]

Let us know what you come up with. Perhaps you could pair this device with a smartphone app, that would take care of the display issue.

It's a fully manual mini gauge, so an app would in no way be feasible lol -- the initial prototype was cardboard followed by some compression rivets and steel pallet banding cut and ground to shape. I have some ideas of how to improve readability, it'll just take optimization of the dimensions, but as it currently stands it's very small and portable, and works down to 0°.

 

[transmaster]

I asked my machinist nephew about this, and what he told me involved a granite surface plate. But he does precision machining for power plants. I don't think accuracy to 10 thou, as they say, is needed.

 

[FortyTwoBlades]

Here's the prototype. No markings have been made on it yet because I need to dial in the geometry first, but as a low-effort proof of concept it absolutely works. Works down to 0° and can open up to 130°. 4" long, 5/8" wide, and weighs only 0.2oz

 

[Old Axeman]

Ben, I was prepared to not like this venture. I was thinking that you might be over thinking the problem. But, I really like the simplicity of your proto type. You are on to something here !
If you get it in production, I think it will be a big help to people that sharpen their tools themselves. But in my case, I probably will continue to sharpen by the "assess geometries by eye/feel" method.
Bernie

 

[FortyTwoBlades]

Yeah I spent all last night scouring the internet for anything like this and weirdly nothing turned up. Doing the math for assessing the angle markings will be a bit of a slog, but once done it should be fairly simple to produce! Simplicity was the goal, and even if assessing geometries by feel, this'll allow us experienced folks to quantify our geometries for others to get a feel for themselves!