HK-40

[Ken S]

I finally got around to making a small knife jig, actually two of them. I made an HK-50 for my T7 and an HK-40 for the T4. For those of you who might not know, the numbers stand for the width of the grinding wheels. The T7 is 50mm; the T4 is 40mm. Since I made both sizes, I call the smaller jig "Hermanito", which is Spanish for "little brother".

The basic concept is the same as the jig Herman built, however, there are some differences. The main difference is that Herman used the SVX-150 Scissors Jig for his small knife jig. I used a  SVD-110 Tool Rest. I appreciate the physics based argument Herman stated for using the scissors jig; the scissors jig does indeed have a lower center of gravity. Quite logical. I also appreciate that Herman was honest enough to state a secondary reason for his choice of jigs; he already had the scissors jack and did not have the tool rest.

In my case, I had a second tool rest already cut in half from a previously unsuccessful attempt. I wanted to use just a Tormek jig for the small knife jig. (Another poster was attempting the same thing recently)

The reason for the narrow diving board is to allow small knives to be sharpened on both sides without shifting the platform.

I used a piece of 6061 aluminum 1/8" x 2" x either two or three feet. I needed to resize the two halves of the platform jig. I was pleasantly surprised to discover that my standard 1/8" (wood) bandsaw blade did the job easily and nicely for both the platform and the jig. A slow feed rate gave a very smooth cut. The "diving board" extends 1 7/8" beyond the end of the platform, although I don't think this dimension is critical. I ground the front of the "diving board" to a bevel with a belt grinder. Aluminum can be gummy, and I did not want to foul my grinding wheel.

I make no claim to being a machinist. I used stainless Flat Head Cap Screws with a 8-32 x 3/8 (inch length). This involved drilling and tapping as well as countersinking the heads. If I ever decide to remake this jig as is, I would either: 1) take it to a machine shop if I was particular or 2) consider using pop rivets, which are much quicker.

In hindsight, the jig would be more practical by using the tool rest as is. I would use ordinary bolts to secure the diving board. The original purpose of the small knife jig is for small knives, which are much smaller than a size which would have problems with bolt heads. That would allow the full size tool rest to be used for its intended purpose and eliminate having to purchase a second tool rest. If the bolt holes were first drilled into a guide block, the same guide block could be used with other accessories for the tool rest. They would interchange using the same holes. I believe the tool rest is a far more versatile jig than is presently used.

Please excuse the necessity of having to use the link to see the photograph. Grepper is helping me into the digital age, but I am a slow student.





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Ken

[grepper]

Nice work there Ken!  Looks good.

Having one of those also gives you the ability to sharpen machetes and other long blade stuff too big for the regular knife jigs.

[Jan]

Good job, Ken. Congrats on your nice HK-40 jig. 

Thank you for sharing your thoughts and the nice photography. It is very inspiring.

Your photo shows the HK-40 placed horizontally, with the stone running away from the edge. Have you tested also the vertical mount, with the stone running towards the edge?

[Herman Trivilino]

Have you tried this jig with the grindstone turning away from the edge? I could never get satisfactory results with this arrangement as the blade keeps lifting off the platform.

Also, what's the smallest bevel angle you can grind with that jig?

[Ken S]

Thanks for the compliments. i have also been working on my knife setting jigs, so I haven't had a chance to give the HK-40 a test run. The platform small knife jigs were originally designed for very small knives which would not fit in the standard Tormek knife jig. These normally benefit from a very light touch and were traditionally hand sharpened on the Tormek with the wheel revolving away from the knife.

This jig would also work in vertical for those of you who sharpen machetes, etc.

Ken

[Fineline]

Hi Ken,
What did you use to slice up the jig. The cut is really nice and clean.
FL

[Ken S]

FL,

Thanks. I sliced the jig with my bandsaw. I just used a standard 1/8" blade and did not rush the cut. I was pleasantly surprised how smoothly the cut was.

Be sure to vacuum out the bandsaw after cutting aliminum. Pay special attention to removing any aluminum from the tires. I unplug the power cord and rub along the tires with a Scotchbrite pad, rotating the tires until both are clean.

Ken

[Ken S]

I had a chance to try the HK-40 with some pocked knife blades today. The problem may well be operator error, however, hand holding the knives with no jig or platform seemed to work better than the small platform. I will continue working on this. Any thoughts on this? (I was using the jig in the horizontal position.)

Ken

[Herman Trivilino]

Try it with the grindstone turning towards the edge. But as I mentioned before, your platform will need to be longer because it's so far from the US.

[Elden]

Ken,
   I tried using the regular knife jig in the horizontal position. It didn't work well for me. I know you said you saw Steve doing that, but for some reason I don't think I am able to do what he does! I was not getting a straight grind. It is time for me to pull out those cheap rummage sale knives and practice!