disc vs. belt

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foxbat34

Joined
Dec 26, 2008
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Just wondering how many of you guys, if anyone, use a disc grinder for primary bevels on a flat grind, and why or why not?

I have a 6" disc and have been using it for some basic shaping but I am going to get a 9" and I was thinking of putting a reversing motor on it, this should allow me to grind the bevel on both sides edge up. Just wondering if Im just spinning my wheels? (pun intended;))

Thanks for the help.
 
As someone who uses both (belt and disc grinders), heres my take.....

For heavy metal removal/belts, I use the belt grinder. For anything 400 grit of finer, the disc is my tool of choice. Basically I setup the blade on the belt, with heavy grit, and then jump to the disc for final machine finishing prior to hand finishing.

I'm a little different in that after heat treating is complete, I take a blade to nearly finished with a 50 grit belt, from there I jump straight to 400 grit on the disc. It generally takes 1 sheet of 400 for hunter sized blades, and one sheet per side for bowie size pieces. I do still use the belt for the convex edges, and sometimes for rolling out the plunge cuts, but its hard to beat the disc for quality of finish and getting things FLAT.

Concerning the plunges with heavy grits on the disc, I think that if you can trim the heavier grit disc(s) very evenly, you can pull it off with practice. You have to train yourself to remember that your not working off a straight cut line....obviously it will be curved on the disc...its a bit more difficult for me to keep things even side to side on those blades I use the disc for setting up the primary plunges, but I've only been trying to do it on the disc for a few months. I've found it easier and more consistent when I set the blade up on the belt with heavy grit belts, and use the disc for finer grits/cleanup.
 
Thanks for the help.

Ed
Thats what i was thinking, it has to be easier to get things flat and straight with the finer grits on a disc. I have Benign tremors (my hands shake) and I have ruined several pieces of steel on a belt once I got to about 400 grit, especially at the tip. It seems that it would be easier to hold the blade flat and still on the disc.

As for the plunges, if I understand what you are saying, you set them up on the belt as normal, but on the disc what is your technique to finish them? Do you change the angle of the blade in relation to the curvature of the disc? Or do you work the blade and then finish the plunges on a belt?

I have seen some knives that look like they may have been done completely on a disc, that is, the plunges had a sweeping curve. That was not a bad look in itself.

Thanks again.
 
foxbat34 said:
Just wondering how many of you guys, if anyone, use a disc grinder for primary bevels on a flat grind, and why or why not?

I have a 6" disc and have been using it for some basic shaping but I am going to get a 9" and I was thinking of putting a reversing motor on it, this should allow me to grind the bevel on both sides edge up. Just wondering if Im just spinning my wheels? (pun intended;))

Thanks for the help.
Click to expand...

I do , only because my belt grinder is a pain in the butt with the platen location . I found 2 things . A file guide on the knife touching the side of the disc helps me to keep both sides even and I visualize a center line across the disc and draw the blade upwards on the disc to keep the plunge straight .
 
Marekz
Im going to mount this in the end of my grinder bench and run it from a motor with a stepped pulley system for speed control, also with a reverse switch. That way i can grind both sides of the blade edge up.
 
foxbat34 said:
Thanks for the help.

Ed
Thats what i was thinking, it has to be easier to get things flat and straight with the finer grits on a disc. I have Benign tremors (my hands shake) and I have ruined several pieces of steel on a belt once I got to about 400 grit, especially at the tip. It seems that it would be easier to hold the blade flat and still on the disc.
Click to expand...


One thing that might help, make SURE to keep your elbows in tight and your hands as close to your body as comfortable.

move the blade with your legs and try to keep your hands still, it makes a LOT more sense if you can watch someone do it but hopefully you get the idea
 
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