Ionut's Small Knife Jig

[grepper]

Regarding my earlier post as to the advantage of the small knife jig (skj) over the IH jig.  I think I've answered my own question.  The answer is edge depth control.

Watching Herman's video, you can see the tendency of the blade to slide up/down on the jig.  One thing that the skj does well is it mechanically controls the vertical movement of the knife against the wheel, as the skj handle rests against the control bar.

Using the IH jig, vertical control over the movement of the blade is a matter of operator skill.  That's how Bob Kramer does it, and of course, if he can do it, it should be a no-brainer for the skilled artisans that frequent this forum.

[Ken S]

Outstanding, Herman!  Good technical video quality and informative.  Your video has all the characteristics of excellent instructional material.

Keep up the good work.

Ken

[Herman Trivilino]

Q:  It's so simple and obvious, why didn't the Tormek engineers make one in the first place?

I think I might know the answer.  If customers pay for this jig, they will be disappointed to see it get damaged.  And it will get damaged.  The metal is so close to the grindstone that it's inevitable that it will make contact.  Of course, the damage is inconsequential, it won't hurt the jig.  If you make it yourself you recognize it as a sacrificial piece of scrap metal and you have a totally different set of expectations.

I suppose you could fashion a wheel on it that rides on the grindstone, but I don't see how you could make something like that adjustable for different grinding angles.

[Herman Trivilino]

Thank you, Ionut.

Also if the jig would be 1/4" or a bit more thick you would have enough clearance from the scissors platform in case of knife wooden handles.

That's an excellent point.  I've noticed that with thicker knife blades that are less flexible the handle does make contact with the scissors platform when I'm sharpening the tip.  I can get around that by moving the knife to the side, but it's definitely an issue.

This is another reason why the jig should be longer, rather than shorter.

[Ken S]

"I think I might know the answer.  If customers pay for this jig, they will be disappointed to see it get damaged.  And it will get damaged.  The metal is so close to the grindstone that it's inevitable that it will make contact.  Of course, the damage is inconsequential, it won't hurt the jig."

Herman, one thing I learned while experimenting with the SVD-110 is how easily the extruded aluminum can be filed with a hand file or worked with a belt grinder.  I see your point with many users, however, we need to drop the reverent attitude toward the Tormek and look at it as a very useful tool.

Ken

[grepper]

My small knife jig is all worn away trying to sharpen small blades!

[Herman Trivilino]

Watching Herman's video, you can see the tendency of the blade to slide up/down on the jig.

There is a tendency for the knife to move down on the jig.  That particular knife that I used in the video has rather narrow face on it, especially near the tip.  Here's a drawing of the cross section.



The knife therefore has a tendency to rock, especially when I get closer to the tip.

When the knife does move down all that's going to happen is you'll round off the side of the bevel furthest from the edge, so it won't affect the edge.


 

[Herman Trivilino]

Outstanding, Herman!  Good technical video quality and informative.  Your video has all the characteristics of excellent instructional material.

Thanks, Ken.  I did make a few mistakes, but perhaps I'll redo it when I make a better jig.  I'm having a trailer hitch installed on my car today.  When I go to pick it up and pay for it, I'll ask if I can rummage through their shop's scraps.  Maybe I can find a piece of aluminum, or stainless steel.

[Herman Trivilino]

Herman, one thing I learned while experimenting with the SVD-110 is how easily the extruded aluminum can be filed with a hand file or worked with a belt grinder.  I see your point with many users, however, we need to drop the reverent attitude toward the Tormek and look at it as a very useful tool.

I agree, Ken.  I was looking at it from the point of view of Tormek.  It may be a marketing issue for them.  In their opinion, of course.

[Herman Trivilino]

My small knife jig is all worn away trying to sharpen small blades!

Your small knife jig consists of a strip of metal that wraps around the part of the knife called the ricasso (yes, I had to Google it).

Did you not encounter any knives with a narrow or missing ricasso?  And how did you sharpen those?

[grepper]

Oh No!  I've screwed up my termology.

By small knife jig I ment the svm-45 as opposed to the svm-140 long knife jig.

With my mini tin can jig, if the blade did not a ricasso, then it would develop one after several sharpenings!

[Herman Trivilino]

With my mini tin can jig, if the blade did not a ricasso, then it would develop one after several sharpenings!

There you go, we'll call it the MTC small knife jig.   

Or, should be called the Ricasso-Maker?   

[Elden]

The next step in development of this jig would be to experiment with different platform lengths. Mine is 4.25 inches and seems to work just fine over the range of edge angles needed for knife sharpening.

It would have a width of 2", a length of about 4",

Herman,

I am working on mine.  How long is your metal plate measuring fro the middle of the USB forward?

I am making mine to be its own jig. A piece of 3/8" pipe is just right to slip onto the USB. That will be welded to a piece of 1/8" thick by 2" wide strap. A hole will be drilled and tapped for a locking bolt with a knob in the 3/8" pipe to lock it to the USB. It won't utilize a Torloc type fit. A hillbilly rigging to simulate that may come later.

[Herman Trivilino]

How long is your metal plate measuring fro the middle of the USB forward?

2-3/8".  It's not a critical dimension, anything close to that will work.

It won't utilize a Torloc type fit. A hillbilly rigging to simulate that may come later.

You could just flatten out the pipe a bit with your hammer.   

Be careful about where you drill the hole in the pipe for the set screw.  It needs to be off-center enough to miss the grindstone. 

Alternatively you could use a piece of pipe that's only 2" long, drill the hole in the center, and then make the plate long enough that the USB will always be well above the grindstone.  With this arrangement you won't have to worry about a knife handle hitting the jig when you're sharpening the knife tip.

[Elden]

Thanks Herman. I am leaving the pipe longer than the strap so it will extend beyond the wheel 1-2". That will be where the set screw is. The pipe is tight enough that it would just barely have space to be flattened. That torlock kind of forms  vee.