Flat Grinding Jig I Finished Today

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bigern26

Joined
Oct 2, 2009
Messages
380
This is A flat grinding jig that I have been working on and finished it this morning. (I Got this idea from another forum)I had to also grind a blade to test it out.
I must say it works pretty darn good2thumbs

All you do it put a knife in it and set your angle by adjusting the wing nuts.
I ground one blade at about 4 degree angle from 90.
I glued leather to the inside of each clamping piece for a better hold.

Sorry for the crappy looking welds, my big welders speed knob broke and my helmet is at work!!

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I think it is a great idea as well although I might have used lock nuts instead of the wing nuts. Two thumbs up from me.
 
I'm not as worried about the nuts moving as I am the whole rear angle strap itself. It looks bendy and flexy.


I would have used angle iron for that right angle, it's much stiffer.

and

Since you are holding it by the tang and that is unfinished, there is nothing to mar up.

I would have skipped the leather on the rear plate

-so that it sits flat against the rear plate and is always holding that angle consistent.



If it helps you get consistent grinds I say go for it.
 
The wing nuts once tight will not move.

Also the rear strap is sturdy, I am not worried about movement.
 
Here's a noob question?

When flat grinding a blade, do you need to rotate it as you get to the point? If so, it seems like a jig like this wouldn't allow that.

What I mean by rotate is so that the grind follows the radius of the curve of the blade edge, if you get my drift. Not sure if that makes any sense.
 
Dropping the butt of the knife is one way to do that. Another is to pull the butt end towards you slightly to grind the tip
 
i like it. is the smaller hinge on the back of the plate just something to weld the bolt to???
 
I made one VERY similar, only much more crude. I use old little c clamps to hold the blade to mine, with bolt heads as a rest for the blade. My view is that the "Flat" part of the grinding maintains the angles between the sides. Creating a distal taper for a slim point is not a problem.
 
bunghole said:
Here's a noob question?

When flat grinding a blade, do you need to rotate it as you get to the point? If so, it seems like a jig like this wouldn't allow that.

What I mean by rotate is so that the grind follows the radius of the curve of the blade edge, if you get my drift. Not sure if that makes any sense.
Click to expand...
I do not drop the point on these drop points, But yeah some designs might have to have the tip down for a proper grind.

Mossanimal said:
i like it. is the smaller hinge on the back of the plate just something to weld the bolt to???
Click to expand...
I welded the bolt to the small hinge for better movement. that way it can tilt alot without binding.
 
nice work! I just use a piece of angle iron and a pair of vice grips (works for any width). but I built an adjustable tool rest, same idea though. I use it for just about everything.

to do the tips you just have to curve the handle toward you as you grind so you keep contact. if its a really wide tip you can angle the knife tip up a little but it seems to work fine both ways.
 
Looks good! I tried this with an angle vise, snapped the first three belts when the edge dug in right off, went back to freehand. Maybe I'll try it again, with a slight bevel to get started so as not to tear into the belt....
 
Tinker Simpleton said:
I made one VERY similar, only much more crude. I use old little c clamps to hold the blade to mine, with bolt heads as a rest for the blade. My view is that the "Flat" part of the grinding maintains the angles between the sides. Creating a distal taper for a slim point is not a problem.
Click to expand...

Mine is even more crude. I use a piece of aluminum angle with different height bolt holes so the top of the blade clears the side of the alum. Held with C clamps. My platen is angle adjustable so I start off with a fairly sharp angle to get started then work it back till I get to the final bevel.

I use it mostly for larger stuff but still do it freehand with the smaller stuff.
 
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