Question for blade makers/sharpeners

jmead · Jun 8, 2020

Is there a product or jig design for pulling a blade accurately past a 1x42 belt grinder? I get good results hand grinding pocket and farm mower blades but I have not tried fine kitchen knives, though I would not hesitate to hand strop with the leather belt. My grinder is the Kalamazoo: 1SM 1 x 42 inch belt sander
I have most grits of belt on the wall.
Regards,
John

Edit: if the most practical answer is to use something like work sharp:
Knife & Tool Sharpener - Work Sharp Sharpeners

When things go back to kind of normal I have friends that can bring theirs when they come up for weekends. They are very happy with it.

eKretz · Jun 8, 2020

There's a guy who sells a clamp-on level jig. Forget his name, Fred something. You clamp the job to the blade blank then set the angle you want to grind at. Stick a small magnetic bubble level to the jig and use it to maintain your angle as you grind.

You could make your own easily enough - or even adapt it with a piece of flat bar and a guide to give you an even easier time of it.

cstrickland · Jun 8, 2020

I have seen several people make their own from a a couple of different ways . I have see them as simple as a piece of bar stock set to the angle and clamped to the sanding table, and I have seen multiple piece jig create

Here is a premade jig for sale on esty ! Bevel Jig For use with file guide | Etsy

I must state I am in no way affiliated nor can I personally recommend this, as I have no experience with it. Just passing on a google result for a jig for sale

Limy Sami · Jun 8, 2020

This one's easy enough Adjustable knife bevel grinding jig for belt grinder knife | Etsy

eKretz · Jun 8, 2020

Ah ha! Remembered the name. Bubble Jig.

The Bubble Jig

Sharps1874 · Jun 8, 2020

Those bevel -- the ones I've seen -- fix the angle for only a single plane incident to the surface of the belt or stone. The problem is that the curve of the blade creates an infinite number of planes at that same angle, each passing through a different tangent along the curve. In other words, the jig might be a help on the straight part of the edge, but it doesn't take away the need for eye/motor coordination on the curve.

Here's what I do. Arrange some good light and blacken both sides of the knife edge with a Sharpie. Using your young, perfect eyes (or otherwise an Optivisor), take off the black with your preferred tool (stone, diamond file, etc.). You will quickly find the right angle, and the bevel will be preserved as you take metal down to the edge. Do each side, renew the Sharpie marks, and go to the next finest stone. I would stay away from the belt sander unless some major reshaping of the bevel is in order.

eKretz · Jun 8, 2020

It sounds like the OP has experience with the belt grinder already. Were he a beginner I would agree, but since he's already got it down he should be fine. I routinely use a belt grinder for reshaping and rebevelling with no issues. I use plain Jane sharpening stones freehand for finish sharpening and minor touch-ups.

dian · Jun 8, 2020

my blacksmith friend who does damascus knives and such starts them on an angle grinder by hand. than he uses diamond plates.

true temper · Jun 8, 2020

I bought a felt belt for my 2x72 grinder, sharpen the knife with a wore out 320 grit and then use the felt. It made my knife scary sharp!

ChipSplitter · Jun 8, 2020

My favorite is mounting a 120 grit 6" grinding wheel in the Bridgeport (yes I know

) and running it at 200ish RPM.

If you get your angles right it does a fantastic job.

BoxcarPete · Jun 8, 2020

true temper said:
I bought a felt belt for my 2x72 grinder, sharpen the knife with a wore out 320 grit and then use the felt. It made my knife scary sharp!

I'll have to try a felt belt sometime. Do you use any rouge or diamond paste, or just the felt itself?

jmead · Jun 8, 2020

Great ideas and thanks! I should probably go back to stones for kitchen knives and make a simple jig. The Bubble Jig in eKretz link looks interesting but I don’t get much from their website. Yes I’ve had this same belt grinder for 10 years or so and I get great results hand grinding all sorts of hedge shears, mower blades etc. but never tried good kitchen knives. I will look into the felt belts, never heard of that. Don’t really see spending $100+ On a jig just to dress up my own kitchen stuff either!

motion guru · Jun 8, 2020

I have watched the knife sharpeners at Benchmade use belt grinders to hand sharpen every single blade that they manufacture. They are the only knife company that I know of that builds up the entire knife with a non-sharpened blade. Its my understanding that the late owner Les insisted that he didn't want anyone getting cut on the job so the last thing done to the knife before it was packaged before shipment was to hand sharpen it. And, if any mistakes were made in this process - the knife was completely disassembled and reworked (and this was very rare).

We have designed a grinder that uses a single grinding wheel to bevel, grind false edge, and sharpen a blade all automatically. It uses a SolidWorks file of the blade to generate the grinding tool path. If you want to spend well into 6 figures on a grinder that can crank out a fully prepped blade every 20 seconds . . .

jmead · Jun 8, 2020

motion guru said:
I have watched the knife sharpeners at Benchmade use belt grinders to hand sharpen every single blade that they manufacture. They are the only knife company that I know of that builds up the entire knife with a non-sharpened blade. Its my understanding that the late owner Les insisted that he didn't want anyone getting cut on the job so the last thing done to the knife before it was packaged before shipment was to hand sharpen it. And, if any mistakes were made in this process - the knife was completely disassembled and reworked (and this was very rare).

We have designed a grinder that uses a single grinding wheel to bevel, grind false edge, and sharpen a blade all automatically. It uses a SolidWorks file of the blade to generate the grinding tool path. If you want to spend well into 6 figures on a grinder that can crank out a fully prepped blade every 20 seconds . . .

�� good stuff Guru but it’s just my own food prep stuff ��
(Those are grinning smileys on my iPad)

true temper · Jun 8, 2020

BoxcarPete said:
I'll have to try a felt belt sometime. Do you use any rouge or diamond paste, or just the felt itself?

I was wanting a leather strop for my 2x72 but didn’t want to spend 50 bux.
I bought a cork and a felt belt on eBay, the cork belt is worthless very rough I don’t know what it would ever be good for. The felt belt is plenty cheep and thin but it works good so far. I loaded it up with white buffing compound. I have a VFD on grinder and I slow it down pretty good.

metalmagpie · Jun 9, 2020

I always thought the way to put a good edge on knives on a belt grinder was to practice until you build up the manual skills to do it correctly.

BoxcarPete · Jun 9, 2020

metalmagpie said:
I always thought the way to put a good edge on knives on a belt grinder was to practice until you build up the manual skills to do it correctly.

I don't know, with a VFD and a nice high-grit belt you can do quite nicely on a lot of things. One of the biggest problems IMO is the belt splice coming around each time. It bumps the work just enough that you can never get a truly great edge. I'm hoping the felt belt I just ordered will make a difference.

I've never been that great with stones, maybe I just need more practice. For most things the belt grinder does well enough for me.

true temper · Jun 9, 2020

Get your edge sharp with a high grit belt, then polish it with the felt,I was surprised how much sharper it was.

eKretz · Jun 9, 2020

jmead said:
Great ideas and thanks! I should probably go back to stones for kitchen knives and make a simple jig. The Bubble Jig in eKretz link looks interesting. Don’t really see spending $100+ On a jig just to dress up my own kitchen stuff either!

Me neither. I just posted the link to give a better idea of what I was talking about. If I needed one I'd make my own too. I've got enough practice sharpening to do without though. I sharpened a knife for my little brother some years ago and he couldn't get over how sharp it was. He told me that he had his friend throwing tennis balls at him and he was attempting to slice them in half mid-air. Actually got some too I guess. The stuff that little brothers get up to... Makes one scratch one's head, haha.

EPAIII · Jun 9, 2020

This is a quite popular subject on YouTube. I only got to "knife sharpening jig " when "knife sharpening jig for belt sander" popped up at the top of the suggested list.

YouTube

It looks like there are a bunch of ideas there. Here is just one that shows the idea that I like. It seems to get around the problem of the curved part of the blade with some simple hand movements. But I have seen better implementations of it so you may want to search further. Some of them had wide clamps for the blade with thumb screw closure.

YouTube

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