Question re: Surface Grinding

A

Altofsky

Joined
Mar 10, 2013
Messages
66
Okay, so like most people, I use a welder's magnet when surface grinding the flats of any particular blade on the flat platen of the 2x72".

What I haven't figured out is a decent way to avoid little scratches on the blade when removing the non-grinding side from the magnet. Little particles always get caught between the blade and the magnet due to.... well, magnetism. And when removing the blade, the little particles undoubtedly leave small scratches on the finish.

I've tried using a sheet of paper between the blade and the magnet, tape, etc... to no avail. Tried keeping that particular magnet separate from the dirty area of my shop and still have the same problem. They almost seem like little microscopic particles getting caught in there, as even after a thorough cleaning, the scratches still appear.

Anyone got any tips or tricks to avoid this? Any help is much appreciated.

Cheers,

Altofsky
 
Just my 2 cents but I only use a magnet on rough grits and do the rest by hand. It will also make your knife a little magnetic.
 
I agree with Dan. I'm not sure if there's a way to avoid the problem otherwise. I tried wrapping my magnet in electrical tape and it was kind of more trouble than it was worth... it didn't take long for the tape to get chewed up and then I had a gooey mess to clean off.
 
Thanks, Dan. I'll give it a go and see how it turns out. Wouldn't be the first time I've ground my fingerprints off. ;)
 
DanGraves said:
Just my 2 cents but I only use a magnet on rough grits and do the rest by hand. It will also make your knife a little magnetic.
Click to expand...

^^ This is what I do too.

Also if you grind it to 120 grit to flatten on the grinder. Start with 100 grit paper or lower when hand sanding. It makes it easier to get a good scratch pattern. I always go down a step when moving to hand sanding.
 
If the blade is clean and you put the tape on the blade I can't see how you would get any scratches. Just my 2 cents.
 
If your knife blade has been unintentionally magnetized there are several "tricks" to demagnitize ferrous metals. The easiest IMO way is to strike the blade with a piece of scrap steel which usually/normally demags them. You can use an electric motors windings to either magnetize or demag by moving the blade through the fields. If I dropped a steel screw where I couldn't grab it by hand I'd magnetize a screwdriver to grab the screw, then just strike the screwdriver on my vice and it was a plain ole screwdriver again, no magnetic attraction.
 
I didn't know that I'll have to give that a try.
It's interesting to me what causes the magnetism. Yesterday I was drilling some 1/2" holes in some 1/2" steel and noticed the bit was becoming magnetizes more than usual. It must be the friction that causes the magnetization.
 
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