Would this jig work?

Varga Knives

Varga Knives

Joined
Aug 12, 2006
Messages
1,302
First of all, I don't want this to turn into a debate on the use of jigs. I understand both points of view and I guarantee you that my first attempts will be free-hand but with the amount of cash I have put into this venture I really need something to fall back on if I suck free handed.

Basically all I have left to purchase is some safety gear and I'm still looking for a good deal on a used drill press. After that I'll be good to go. My KMG is all set and runs great! So...

I have read tons of posts on knife making and watched lots of vids. The only part of the process that has me doubting my abilities is grinding the bevel. What I would like to make are large fixed blades so that is what I hope this jig would aid in. I see immediate problems in this jig on smaller blades where the edge doesn't stay parallel to the spine for very long but that's not an issue for me.

I started with some rather complex ideas and plans but kept going simpler and simpler and here is where I am now.

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Sorry for the crappy drawing but I'm no artist and only had a pencil with no eraser and a book to use as a straight edge, but I think I get the idea across.

The material list is: 4"x1" block, (2) .5"x3" pieces of mild steel, and whatever to use as a block guide. That's it. The fence needs to be at 90 degrees to the work rest and the bevel angle would be set by adjusting the platen. Let's say toeing it in 4 degrees for my purposes.

The block would be under some pressure in the block guide but would be able to slide closer to the belt after each couple of passes. The lower edge of the blade would need to be kept firmly against the fence and the problem here is that maintaining that pressure would be increasingly difficult as the bevel is brought down towards the spine (less surface area in contact with the fence) but then again it may not be a problem since, once the initial bevel is created and large enough, there should be adequate suface area there to self align with the belt. I have some rare earth magnets just lying around at home and I was thinking of mounting them flush or behind the bottom of the fence to pull the spine in (black dots in pic). I dunno, like I say, it may not be necessary. One hand would be kept on the block with knuckle pressure towards the center of the belt on the spine. As the blade is pulled across and the tip gets nearer to the belt the handle is brought down, keeping the edge high and the spine only contacting the trailing (or would it be leading?) edge of the block.

I hope I explained it okay.

I will either make this jig and try it or defer to your expertise and scrap the idea if it's garbage. So, will it work?
 
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You should be able to post the picture yourself using a third-party hosting site like Photobucket.
 
If you are just starting out and want to teach yourself to flat grind, free hand; take a look at the Bubble Jig. It makes flat grinding fun.


Happy grinding, Fred
 
With a KMG flat platen it shouldn't even be that difficult. Set the desired angle on the adjustable platen and use some vice grips to hold a piece of angle to the work rest.
 
looks like a decent idea... looking forward to seeing it in action. im making my first jig now as well, using angle iron however.
 
Just my opinion but I have the same issue as you. Was very tempted to make a jig for flat grinding (there's a very good one on YouTube) to speed things up but I rationalized that in the long run it would just hurt me. I would have to say if you used anything I would go with the bubble jig which is on my must have list when I can afford it. Until then, I practice on mild steel and work to my technique which is getting better but I need more practice.
 
I bought a Bubble Jig and it looks like a good product honestly, but I still haven't brought myself to use it. I want to see what I can do freehand/workrest after 10-20 blades, and if I see a marked improvement as I work, I may never use it.. but it's there if I need it I suppose. How many have you ground so far?
 
Thanks guys but I'm still really just looking to see if it will work or not. I'm probably only a week away before I can start grinding so I may just see for myself.

I do like the Bubble Jig and the whole kit's not that much money but I already have the items to put mine together and it can't take more than 10 minutes to make.

The problems I see (and I could very well be wrong) with the angle iron are 1) not being able to bring the handle down to thin out the tip. I read some good stuff, particularly from Rick Marchand, on the subject and I think the handle needs to be drawn towards you to thin the tip. I just don't think of this as being as consistent. 2) having to precisely mark the blade in the fixture so as duplicate the blade level on each side. 3) having to remove the blade from the fixture each time you want to switch sides. If you had a rest which extended beyond the belt on either side then an angle fixture could easily be made to work both sides without removing the blade but...
 
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The bubble jig will keep you honest while you grind. I have used it on many blades and now really do not need it at all to keep the grind angle consistent. But on that rare occasion when things just are not going right I will pull out the Bubble Jig and grind both sides and it can pull you out of a problem you otherwise would be chasing all day.
 
Even for a simple jig, your design seems too complex for my liking. Some folks have suggested freehand grinding or Fred's Bubble Jig.(I've heard good things about that little unit. Makes me wish I used the grinder more often... lol.) I like the idea of having a jig that lets you freehand at the same time. A jig that comes to mind is the one that member Chainring made. It really doesn't get much simpler and you have more freedom to follow upswept edges.

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I was on this thread this morning and when I read, there was a Bubble Jig stashed away in a drawer somewhere in Ontario I got a little sad. You have locked away the very best grinding teacher that can be had, anywhere at any price. She wants out of there.

No really, my invention is the best kind of teacher; you learn by doing. It makes you get better. Using this grinding aid doesn't hinder what you do, it broadens what you can grind.
I've ground 500 blades with this system; I can grind without it, but I chose not to, I grind a lot more relaxed using it. Try it out; you will learn in a hurry what it takes to hold a constant angle.

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Thanks Rick. You have me pondering that picture... I think the principle is essentially the same with the main drawback to Chainring's design being it is not adjustable whereas the other is. To simplify mine and bring it more in line with Chainring's, though, the block could be dropped off all together. Now it would basically be two 90 degree angles bars. One on either side of the belt and their faces on plane with each other and perpendicular to the rest. Hmm, it's hard to explain it exactly but if you can picture a big block letter "U" with the two upright parts bent at 90 degrees to the bottom. The bottom of the "U" could be clamped under the work rest.

You would adjust the distance of the work rest back a little so that the plane of the "U" fence intersects the plane of the belt (set at whatever angle) probably around mid-platen.

Whatcha think?
 
All right, Fred. Upon your recommendation and many others I will pick one up. I'd still like to see how the above jig modification would work out. I think it could be a winner, too. :)
 
Fred.Rowe said:
I was on this thread this morning and when I read, there was a Bubble Jig stashed away in a drawer somewhere in Ontario I got a little sad. You have locked away the very best grinding teacher that can be had, anywhere at any price. She wants out of there.

No really, my invention is the best kind of teacher; you learn by doing. It makes you get better. Using this grinding aid doesn't hinder what you do, it broadens what you can grind.
I've ground 500 blades with this system; I can grind without it, but I chose not to, I grind a lot more relaxed using it. Try it out; you will learn in a hurry what it takes to hold a constant angle.

DSC01511.JPG
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Perhaps you're right Fred, and I appreciate the advice hehe. Part of it for me (and may help you with marketing as well) is that it doesn't come with instructions. Your videos are very informative but I watched them weeks before I got the jig and just never went back to study and take notes. It's not all that complex, it's just that I forgot the finer points.

I will give it a shot I promise! I just want to see what I can do by my own wits first. I do like the idea of being more relaxed about the grinds though, really that's the most stressful thing for me as a new maker is keeping a constant angle. One time I did it very intuitively, and this last one was quite faceted (though I want to blame a dull belt and slightly hollowed platen, it was mostly me).

Tell you what, once I do some with the Jig I'll post pics. I need to do a newbie WIP eventually anyway.

RIck, I like that guide too, it looks like it would be good for Scandi grinds too?
 
strider214 said:
All right, Fred. Upon your recommendation and many others I will pick one up. I'd still like to see how the above jig modification would work out. I think it could be a winner, too. :)
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You will get so much out of grinding with this set up; you'll be amazed at what you learn about grinding blades. Make your jig and see how it works for you. Once you get used to the Bubble Jig you wont grind any other way.
mgysgthath said:
Perhaps you're right Fred, and I appreciate the advice hehe. Part of it for me (and may help you with marketing as well) is that it doesn't come with instructions. Your videos are very informative but I watched them weeks before I got the jig and just never went back to study and take notes. It's not all that complex, it's just that I forgot the finer points.

I will give it a shot I promise! I just want to see what I can do by my own wits first. I do like the idea of being more relaxed about the grinds though, really that's the most stressful thing for me as a new maker is keeping a constant angle. One time I did it very intuitively, and this last one was quite faceted (though I want to blame a dull belt and slightly hollowed platen, it was mostly me).

Tell you what, once I do some with the Jig I'll post pics. I need to do a newbie WIP eventually anyway.

RIck, I like that guide too, it looks like it would be good for Scandi grinds too?
Click to expand...

I used to put an instruction sheet in the package but I couldn't make clear what I wanted to say. Its a tool that you learn by using it. Use the three point grip like you see in the videos; with your thumb on the loop of the clamp. It gives a lot of control. This is what I send out when I ship; if you have not seen this it will help get you started.
I would appreciate your feedback; being a reluctant user you will give an unbiased assessment. :)

To start place the bevel angle clamp in a vise; load it with a piece of flat stock, long enough so you have a handle to grip and 3 inches on the blade side of the clamp. Using the 5 degree wedge, center the bubble. Use the 5 degree setting to grind the edge to just under heat treat thickness. As you grind at this angle, the edge will narrow and the grind lines will move up. When you have the edge to the pre heat treat thickness; check the height of the grind lines and make sure there equal. If one line is lower, make a couple of passes on that side and bring it up.
If the grind lines are high enough, stop, if not change the bubble setting from 5 to 4 degrees, [ stack the wedges for different degree settings. ] center the bubble place it on the clamp and grind. The grind lines will move up as well as move towards the edge. When the gl are at the desired height, stop. If not drop the angle setting. Nothing is set in stone as to degree setting. I might change from 5 degrees to
2 1/2 degrees on a large bowie. Experiment and you will find what works for the blades your are grinding.

If the grind lines are even and just a little under the finished height, stop grinding. Take the clamp off the blade. Use the even and flat bevels to finish; step down in belt grit at this point, I go from
36 to 60 grit ceramics and leave the blade at 120 finish before heat treat.

Taking time to do a couple of practice grinds will pay big benefits.

Happy grinding, Fred
 
Thanks Fred. I will certainly give you an unbiased review when I get to play with it. Sorry didn't mean to hijack this thread guys. Not feeling too well today but I'll see if I can get some time this weekend to grind some blades with it.
 
Your jig would work, Fred's is awesome! With the KMG angle-able platen though and ample work rest space, for Jig grinding I prefer the one I came up with, the Grindomatic 5000. You figure out your blade angle, set your platen, scribe your blade's centerline then grind away, very even smooth results with minimal practice. And all it is is a piece of angle iron with some drilled and tapped holes that adjust in and out for blade spine thickness, and a c clamp on the tang end.

This is if you do not want to get better at grinding, it does it for you. Fred's Bubble Jig will help you be a better grinder, this will grind for you.

I am not selling these, why would someone buy angle iron with bolts through it, also a bette rreason to buy Fred's because it supports an awesome knifemaker.
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When you posted this earlier, I thought Godzilla fixture! Just the thing for a longer blade; they are so hard to grind, really true. Simple fixtures are the best, they're easy to build, use and repair. Someone remarked to me, Simple, Stupid when they saw the original bubble jig, a compliment, I think.

Thank so much for the kind words Sam, made me smile, Fred
 
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