Residual Magnetism

[Rollie Kelly]

Anyone using magnetic bars to hold their chisels experiencing issues with swarf bonding to the blades during sharpening?

Thanks,
Rollie

[Howard Pollack]

Yes, I stopped using them for that reason. -Howard

[Tom Stenzel]

Same problem here. I kinda liked watching the swarf chase the chisel around. Then again I am pretty easy to entertain.

-Tom

[Jim Koepke]

This has long been one of my objections to magnetic knife or tool holders. This is also why none have ever been used in my house or shop.

jtk

[Andrew Zetts]

You can fix this by either going on a cruise across the equator backwards or by buying one of the following:

https://www.amazon.com/dp/B016TK6LGQ...f-8d3178d83a22


Caution: failing to follow these precautions may make you more susceptible to naval mines.

[Mel Fulks]

And plenty of those old tape recorder demagnitizers are out there.

[Tom Stenzel]

I've got an old CRT television in the garage. My daughter got a hold of a magnet and had great fun moving around on the screen and making the colors swirl. When she was done the screen was a mess. I don't have a demagnetizer an didn't feel like buying something.

I used my cordless drill with an eye mounted in the chuck, a short piece of string tied to an old speaker magnet. I used the drill to spin the magnet as I brought it up to the screen, moved it about and moved it away. It worked on the TV, it should work on a chisel. If you have this stuff already it might save buying yet another thing to have lying around the house to use once every other 10 years.

-Tom

[Jim Koepke]

Somewhere in my junk is an old DC motor casing. It has two ~half cylinder magnets attached. At one time it was used for magnetizing a screwdriver when needed. It could also do the work of demagnetizing by holding the screwdriver in the center of the cylinder and inserting and withdrawing a few times while also slowly rotating the tool.

An AC magnet, like a tape erasing tool works by alternating the field 60 times a second as the eraser is drawn away from the tool so the field is weaker when the eraser is turned off.

What is fun with an AC magnet is some of them will pick up aluminum or other nonferrous metals. Some metals may require a frequency other than 60 Hz to do be attracted.

jtk

[Rollie Kelly]

Thanks all.

[John K Jordan]

And plenty of those old tape recorder demagnitizers are out there.

That's what I use, an old bulk tape demagnetizer. Steel can become magnetized from the earth's field without even coming in contact with a magnet - a big pain for me when sharpening lathe tools on a dry Tormak CBN wheel.