Who's made a sharpening jig?

L

Lavan

Joined
Nov 8, 2000
Messages
2,301
I was just considering a Rube Goldberg setup with maybe a plastic block that could be set ...NEXT TO.... a whetstone or diamond stone.
By spacing the block at a certain distance from the stone, almost any angle could be made consistently. As long as the block distance didn't shift.

Whaddya think?

:confused:
 
By your description this block is "next to" the hone and located a variable distance from the hone to set your angle. Something is missing in your description. I don't see how your block is interacting with your hone except maybe from gravitational attraction.

What I have done is set a block under a hone to prop it up on an incline. Then I could hold my blade horizontal and hone at a calculated angle. This could be extended by puting the hone on a board and putting the block under the board. This would allow the block to be out from under the hone and allow a finer angular resolution.
 
Jeff, your rig is too dang simple. I never ....THOUGHT....of angling the stone.

Ergo....the concept is faulty. :D

What I was thinking of was varying the distance from the block to the stone and sliding the blade along the block so it would contact the stone at whatever angle you set. (by spacers from the block to the stone)

Now....YOUR.... idea would require that you simply slide the knife on a flat surface while the stone is tilted to the desired angle.

I'd better quit now or I'm gonna ask about maybe making some tilted STICKS of abrasive that one could just slide the blade along, and that would be ridiculous.

:rolleyes: :D
 
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I've been struggling to visualize your idea. How about this. You have a flat hone and above it you affix (magically for the moment) a similarly shaped block of plastic. The block is parallel to the hone and provides a fixed gap between the two flat surfaces. You insert a knife blade into the gap. The knife blade is considerably wider than the gap. If you apply a little twisting pressure to the knife the edge will touch one block while the spine will touch the other. You want to twist the knife in the direction such that the edge comes in contact with the hone. The width of the knife and the spacing between the two planes determines a fixed honing angle. If the gap is adjustable the honing angle is adjustable. Is this starting to approach your idea? The design I described would work best on very straight knives like kitchen slicing knives.
 
As I see your picture you rub your blade against the hone by sliding it lengthwise rather than the normal cross-wise. Is that how it works?
 
I made this digital sketch of a wooden jig for holding sharpening stones a while back and have linked it on BFC a few times already. You could make it out of scraps of wood, a couple screws to hold the upright brace, and a dab of glue for the stop block.

To change the angle you could rig block(s) of wood to hold the top of the stone away from the jig or else run a deck screw into the upright brace (screwing it further in/out of the brace to change the angle).

stone-jig.jpg
 
Below is drawn another angle-maintaining jig that was shown to me in real life by a friend. His was just a notch cut into a piece of pine 2x4 lumber.

To sharpen the full length of the blade, he moved the knife blade slowly forward-and-back through the notch as he slid the sharpening stone back-and-forth (perpendicular to the blade edge) across the opening of the notch. The stone never moved so far that it lost contact with the section of the edge that was being sharpened.

My friend recommended the 1:4 ratio of depth (D) to length (L) of the notch, as shown in the graphic below. That works out to being roughly 14 degrees per side, or a 28 degree total angle. The math to figure this out is: Angle-per-side = arctan (D/L). If you increased the ratio to 1:6 it would give you about 10 degrees per side.

The spine of the blade is held down in a lower corner and the edge should just reach the upper opposite corner of the notch, where the edge will make contact with the moving sharpening stone.

Note that this jig is not particularly adjustable. His was set up for basically one angle on one height of knife blade (spine to edge dimension). For different angles or taller/shorter knife blades, you'd make more notches in your board with differing depths and lengths.

stone-jig_notched-board.jpg
 
I made this jig several years ago that would hold diamond stones at the same angle as the back bevel setting on the Sharpmaker. I sold it after I purchased an Edgepro, but used it successfully for a long time.


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I had my stepfather make 2 jigs like the ones posted by rokjok in his first post (his miter saw after all) exept instead of cutting the angle the long way on the bearing for the stone, he just cut it along the short side of the wood that screws to the base. I have one at 12 degrees and one at 17 to use on the respective sharpmaker angles of 15 and 20.
 
I have made wooden jigs for sharpening both axes and meat cleavers which work very well but drew the line at knife blades. Instead I bought a Gatco sharpening system which is very easy to use and in my opinion produces fabulous results. Incidentally I still get great pride from producing a superbly sharpened blade, even with a shop-bought system.
 
I'm torn between the creativity of making jigs and the pleasure of getting something to come out to machine tolerances by hand work. When it comes to sharpening my creative side usually gets ripped instead of sliced. One problem is that I like a blade that has a lot of curve to it, about 3/8" in 6", convex on one side, concave on the other almost like the pitch on a prop. I have been thinking that by clamping a couple of brass plates to the riccasso and letting them slide along adjustable rails either side of the stone I could duplicate the motion of my wrist but so far its just been easier to sharpen by hand than to make the jig.
 
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