Grinding pocket knife blades on a Belt Grinder

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Ozwelder
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Grinding pocket knife blades on a Belt Grinder

Post by Ozwelder » Wed May 27, 2020 2:23 am

I have ground plenty of fixed blades on a belt grinder.

I am about to make my own blades for pocket knives. I am at a loss to figure how to hold the pocket knife blade as there is not much metal projecting past the end of the end of the belt edge to obtain a secure grip.

Hand held is not an option as I am not strong enough in the fingers to get a secure grip.

To ensure a precision grind obviously the blades must be held rigidly.

I tried using vice grips but the blades sometime slip but the vice grip jaws mashes up the pivot faces on my practice pieces.

Is there a jig I could fabricate? I surmise it would incorporate two holding points ,a screw through the pivot hole and a flat edge to prevent the blade edge from swiveling down.

Does that idea sound feasible? Advice from someone who has ground folder blades on a belt grinder would be appreciated.

The other way would be to leave an extra length of metal past the pivot area and treat it like a fixed blade and remove the excess later..
i have a look on Utube and other places on the internet but specific information on this topic is not easy to find.

Thanks for your time

Ozwelder

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FRJ
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Re: Grinding pocket knife blades on a Belt Grinder

Post by FRJ » Wed May 27, 2020 2:34 am

Did the boys back in the day do it after some assembly?
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Reverand » Wed May 27, 2020 2:42 am

https://youtu.be/lXtYfbPTTc0

For full disclosure, I have NOT made one of these grinding jigs yet.
YET. But I intend to try it!

You could even make them in a couple of different sizes (for smaller blades), and I like your idea of another screw for the pivot hole.
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Ozwelder
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Ozwelder » Wed May 27, 2020 3:15 am

Crikey that was quick! :D :D

Thank you both gentlemen.

I shall post some pics when I git er done.
I had seen the vid but i was too thick to have it sink in. ::dang::

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Re: Grinding pocket knife blades on a Belt Grinder

Post by tinkerer » Wed May 27, 2020 1:48 pm

Here's a video showing the traditional method in Sheffield. Looks like they use a handle type clamping jig.

https://m.youtube.com/watch?v=SlO-fo_xLRU

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muskrat man
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Re: Grinding pocket knife blades on a Belt Grinder

Post by muskrat man » Wed May 27, 2020 7:39 pm

When you cut the blank make two blades that are connected at the tang then you can cut them apart after grinding so you have one to hold onto while you grind the other. Another option is to leave a nub on the end of the tang to clamp the vice grips too, if they are tightened correctly they wont slip while gridning. If it marrs up the metal it will be on the nub that you can cut/grind off when grinding and polishing is complete.
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Re: Grinding pocket knife blades on a Belt Grinder

Post by muskrat man » Wed May 27, 2020 7:40 pm

FRJ wrote:
Wed May 27, 2020 2:34 am
Did the boys back in the day do it after some assembly?
I do it that way often. temporarily assemble the blanks after fitting, grind the blade using the handle as....the handle. then you can cut it apart and do the final assembly.
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Jeffinn » Wed Jun 10, 2020 3:23 pm

I made a few of those grinding jigs this week. I had to modify his plan just a bit due to the thin blades that Im grinding but other than that, they were easy to make, relatively inexpensive and work pretty well.
6B97B6E2-2D07-4A03-A363-EE0CB5A81072.jpeg
FEF44519-09FD-4D68-91C6-2954090CA21C.jpeg
When I used the screw heads as the blade rest (like he did in the video) the grinding belt ground off the screw heads. So I switched over to the thin brass metal strips and for my particular need they work just fine. That and I allowed a bit more than 2” between screws to allow the grinding belt to work without contacting the screws.
I’m working with some Schrade sheepsfoot surplus blade slugs that need to be profiled. The angle needed is much less than I would have thought but after four blade trials I’m getting close to where I need to be. I’ll need to round up a few more finer grits in some good metal cutting 2 x 72” belts and adjust the angle just a bit more.
The top blade is the factory slug with no bevel, the second blade is a factory ground blade and the third blade is my latest effort at grinding a blade bevel.
57ADB9B8-6746-4D51-9FC3-7488D5A095A0.jpeg
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orvet
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Re: Grinding pocket knife blades on a Belt Grinder

Post by orvet » Wed Jun 10, 2020 4:21 pm

Looks good Jeff! ::tu::

Did you have to anneal the blades before grinding them? I was told that the blades were blanked, hardened and then ground on machines that had a cooling/lubercating fluid that poured over the blades so they didn't overheat.
Grinding them after hardening them at full thickness prevented warping.

I have a bunch of blanked & hardened Schrade & Camillus blades and I was wondering how hard they are to grind with a belt grinder?
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Jeffinn » Wed Jun 10, 2020 4:45 pm

Hi Dale,
I tend to agree that the blades are already hardened.
For initial grinding I used some new ceramic belts in 80 grit and 120 grit. The ceramic belts seem to grind without too much pressure or effort so hopefully overheating shouldn’t be a problem. I tried a few aluminum oxide belts in finer grits and although they seemed to work okay, it took considerably longer and the longer times on the grinder did produce some heat. And the AO belts had a very distinctive “thump” from the seam each time it passed the platen. (The thumping may be indicative of a lower quality belt though as I generally only use those for shaping knife handles).
It looks like Supergrit.com carries ceramic belts in a variety of grits up to about 220 which would probably produce an acceptable blade finish. I’m going to order a few of those this week and give them a try. As a FYI, I’ve ordered from them a couple of times and have been happy with the quality of their belts and with their order and delivery process.
Jeff
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Re: Grinding pocket knife blades on a Belt Grinder

Post by tinkerer » Wed Jun 10, 2020 5:30 pm

If they're hardened & tempered, it should be fine to grind them as long as they don't overheat enough to affect temper. The thinner and shorter they are, the easier they are to get hot.

My rule of thumb is if they're getting too hot to touch, dunk them in water to cool. I feel I've had good results with maintaining temper with that method.

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Re: Grinding pocket knife blades on a Belt Grinder

Post by Reverand » Thu Jun 11, 2020 2:40 am

Looking good, Jeff! I expect that soon we won't be able to tell the difference between Factory-ground and Jeff-ground blades! I am glad to see that those blade jigs work, especially with your improvements. I haven't tried building one yet, but fully intend to soon.
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Ozwelder
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Ozwelder » Thu Jun 11, 2020 3:26 am

Thank you gentlemen,
One and all.

Excellent information.

Thanks
Ozwelder

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Jeffinn
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Re: Grinding pocket knife blades on a Belt Grinder

Post by Jeffinn » Fri Jun 12, 2020 2:48 am

orvet wrote:
Wed Jun 10, 2020 4:21 pm
I have a bunch of blanked & hardened Schrade & Camillus blades and I was wondering how hard they are to grind with a belt grinder?
As a FYI, I had no intention of getting into blade grinding but a lot of the Schrade 34ot blades that I bought were blanks that needed to be ground. And the only 8ot Blades that I could find were also blanks. I haven’t seen any other 8ot blades out there so I decided to try these jigs.
It looks like I should be able to get some acceptable blades using these jigs and some ceramic belts and it opens up some other possibilities for me going forward.
Thanks to the poster who pointed out that video, once I got a look at the parts list everything else was pretty straight forward!
It’s why I like this group so much, I always get the info or the parts or the knowledge that I need!
Thanks everyone!
Jeff
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