Thinning steel on disk grinder?

Jesse Smith

Jesse Smith

Joined
Dec 2, 2013
Messages
163
I'm building a folder and need to get the blade thinned down by .020" at minimum. I have no surface grinder, and I'm told Wade Colter does this on a disk grinder. However, after wasting an hour last night I have 4 bloody fingers and a blade that is a whooping .004" thinner than when I started. Any advise from the pros? I mean, advise other than get a TW-90 with the surface grinder attachment, because that IS going to happen eventually, someday, I hope. ;)
 
What grit paper are you using? I tend to use 36 grit, or at most 60 grit on a 2X72 grinder when desiring to thin 'n flatten a blade. Also, the idea of using a magnet is a GREAT idea - something on the order of item #41629 from harbor freight, or perhaps this http://www.amazon.com/dp/B000UVMJKS/

I've been using similar magnets for a couple of years and they work pretty good. I do expect there are better, but it's what I've got.

Ken H>
 
Use some good double sided tape, like carpet tape. I used normal double sided scotch tape when trying to flatten some thin micarta a couple weeks ago but it get "unsticky" pretty fast. ;)

~Paul
My YT Channel Lsubslimed
... (It's been quite a while since I've posted any new vids)
 
Ken H> said:
What grit paper are you using? I tend to use 36 grit, or at most 60 grit on a 2X72 grinder when desiring to thin 'n flatten a blade. Also, the idea of using a magnet is a GREAT idea - something on the order of item #41629 from harbor freight, or perhaps this http://www.amazon.com/dp/B000UVMJKS/

I've been using similar magnets for a couple of years and they work pretty good. I do expect there are better, but it's what I've got.

Ken H>
Click to expand...

I have those type of welding magnets a few feet from the disk grinder. I never thought to try them. I thought I needed a heavy duty material transfer type of magnet, but come to think of it, I bet it works well. I'll try one of them next session.

So, I'm thinking the paper is my issue. I was using 220 as that is the most coarse paper I had in full sheets of aluminum oxide. I tried a sheet of 120 garnet? but it wouldn't even turn the scratches after the first minute or so. So I went back to the 220. I'll stop at the hardware store and see if they have anything more coarse in aluminum oxide.
 
I did this for a few years when started making damascus folders from forged stock, but I used a 2x72 grinder and 36-60 grit ceramic belts.

220 grit ain't ever goin to do it!
 
I've tried the 60 grit Blaze Plus ceramic discs and the welding magnets but I still haven't been successful. I don't seem to be able to control the steel well enough while grinding, especially using the magnet and I get a piece of steel that's thin on one edge and thick on the other. Without the magnet I get the burned fingers and bloody knuckles the OP mentioned.
 
I've started wrapping a couple layers of athletic tape around the 2nd and 3rd joint if my first finger on each hand. This gives me a little buffer from the paper. The paper will eventually eat through it but it's pretty easy re wrap your fingers. I've also had a lot of luck using a small welding magnet like some of the others have mentioned.
 
What Don said, When you get to 220 grit, you are right on the border between grits that will remove material and ones that are merely removing the scratches from the previous grit.
 
woodwrkr221 said:
I've tried the 60 grit Blaze Plus ceramic discs and the welding magnets but I still haven't been successful. I don't seem to be able to control the steel well enough while grinding, especially using the magnet and I get a piece of steel that's thin on one edge and thick on the other. Without the magnet I get the burned fingers and bloody knuckles the OP mentioned.
Click to expand...
Better to use a 2x72 belt, then finish on a disk. You also have to keep flipping the piece around and constantly checking thickness.
 
A disk is the worst type of grinder (slowest) for reducing stock thickness or stock removal. It is good for finial finish though.

Before I got a surface grinder I was doin this just with damascus I made. For mono steel I just used precision ground tool steel. It's not worth the time or headache to do this if it's not absolutely necessary.
 
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