Grinding Magnet

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Nov 23, 2003
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Do any knifemaking retailers offer grinding magnets/bars for mill scale and flattening of blade stock?

Ideally, these should support at least 6" blade of material and be capable of withstanding temperatures in excess of 350F.

My magnet system works, but is not adequate.

Thanks,
 

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I use a welding magnet like this. Its pretty hefty and holds well even when I'm bearing down on the grinder.
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Well, a note on the scale. You can easily remove that by placing your cut out blades or steel pieces in some vinegar or weak acid such as ferric chloride very diluted. The magnet thing does work well. I bought a large one that was two put together, cut it length wise, placed the pieces end to end on a piece of hardwood and have been using it for many years.
Frank
 
Just checked Texas Knife Supply I purchased mine from and unfortunately they're out. I also checked Jantz, Pop's Knife supply and USA Knifemaker and they don't carry any that I can see.
 
I bought a 100 pound magnet from Princess Auto. In hind sight a 50 pound magnet probably would have been more than enough.
 
I use one of the 9" knife makers magnets from Texas Knife Maker, but as mentioned, it seems to be currently out of stock. Sheffield Knife Makers Supply also carries one exactly like it though.
 
Here are photos of the type of blocks I make to flatten my steel. I have three different welders magnets but I do not like to use them. I have not tried the magnetic holder sold by Jantz. I have made about 5 of these in lengths from 8 to 10 inch's with an array of rare earth magnets numbering from 7 to 10 magnets. These hold my blades tight but I can slide them off easily. I have more than one block because I flatten two or three different blades at a time on my 4 x 36 first and then my flat platen and finally my 9 inch disc sander. I am not saying that this method is the best but it is what I came up with and it works for me. The wood is oak or any hardwood in 1x2 and I epoxy two of them together. The magnets are mail order and are 1/2 x1/2 inch cylinders and I drill tiny bleed holes in the bottom of the 1/2 inch holes. I epoxy the magnets in place and I epoxy the thin steel cover plate and anchor it at the bottom with a couple tiny brass pins. I small piece of sheet metal with two self tapping screws fit the bottom end and it sticks up just enough to keep the blade from launching off the flat plane. It doesn't take long to make two or three of these and they work well for me...maybe you too. Larry PS you can see a low spot from the layout blue left over on this blade. LL
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I got mine at kj magnetics online. You can get various ones and make your own block. Like lo/rez said. I went with the strongest I could find first, but stick mostly to a magnet in the 70 lb range that attaches to an eye bolt.
 
LARRYZ10 said:
Here are photos of the type of blocks I make to flatten my steel. I have three different welders magnets but I do not like to use them. I have not tried the magnetic holder sold by Jantz. I have made about 5 of these in lengths from 8 to 10 inch's with an array of rare earth magnets numbering from 7 to 10 magnets. These hold my blades tight but I can slide them off easily. I have more than one block because I flatten two or three different blades at a time on my 4 x 36 first and then my flat platen and finally my 9 inch disc sander. I am not saying that this method is the best but it is what I came up with and it works for me. The wood is oak or any hardwood in 1x2 and I epoxy two of them together. The magnets are mail order and are 1/2 x1/2 inch cylinders and I drill tiny bleed holes in the bottom of the 1/2 inch holes. I epoxy the magnets in place and I epoxy the thin steel cover plate and anchor it at the bottom with a couple tiny brass pins. I small piece of sheet metal with two self tapping screws fit the bottom end and it sticks up just enough to keep the blade from launching off the flat plane. It doesn't take long to make two or three of these and they work well for me...maybe you too. Larry PS you can see a low spot from the layout blue left over on this blade. LL
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3TgZ5Abl.jpg

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Click to expand...

This is an awesome idea. Would you mind if I did something similar?
 
Lo/Rez, I took these photos because I thought they might help somebody make a better knife. Please make your own and tell us how they work for you. Larry
 
It's taken me a couple of days to reply to my original post, but the responses have been most helpful to me.

I finally resorted to stopping by Harbor Freight and picking up two magnets. One is the red welder's magnet that Shane_o-co mentioned above, and the second is a 150 lb retrieval magnet. After a bit of use, I think I like the red welder's magnet. I found that both of these magnets have the actual magnets recessed into the metal bodies of the assemblies. This helps to keep temperatures down, and allows easy cooling when dunked in a bucket of water.

My application needs are for flattening blades immediately after they have been profiled. This builds a large amount of heat when I'm trying to get the last life from older 36 and 60 grit belts.

I considered fastening magnetic disks into multiple counter-bored holes down the length of a metal flat bar. My research showed that the old stye Alnico magnets are good for temperatures above 900F, but they are fairly brittle and I couldn't find them with countersunk holes which would allow them to be fastened to the bar with flat head cap screws. Samarian Colbalt magnets are good for temperatures in excess of 400F but they are expensive and also are not available as countersunk disks. The new and popular Neodymium magnets can permanently loose magnetic strength if heated above about 300F.

Anyway, thanks to all.
 
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