Monday, April 21, 2025
Bad idea #118-b: Cutting magnets
The stage for clamping slides to on μRepRap uses magnets. I have a few 30x10x2mm magnets ordered years back, so I used them. Now I need to make another stage, but turns out in NZ/Australia ordering magnets in that size is nigh impossible. It's almost as if there's some stupid restriction.
Anyway, I can order 60x10x3mm magnets. So cut one in half, right? Now cutting magnets is a bad, bad idea. They tend to explode, shatter into sharp fragments, generate toxic dust etc. In other words, my everyday life.
Apart from protective gear, you need non-magnetic tools. I marked out a cut line by scratching in Sharpie marker, having measured with plastic callipers. Score both sides so that if it cracks (and it probably will) it splits cleanly.
Next, out with a fine Dremel cutting disc and the everything-proof filter mask. I used Gaffer tape to secure the magnets to a strip of scrap steel. This stops things flying around, gives clamping area that won't magnetize my clamps, and acts as a heatsink - magnets lose strength when overheated.
It was a very sparky cut, done in many small passes. Looks like I missed the scratch, but I realised a mistake and corrected the mark.
After the cut, two magnets. Clean off fragments and magnetic dust with more Gaffer tape.
Finally, fit into the XY Stage. Damn. Forgot the old magnets were 29mm long, so this is going to take a bit of forcing or a reprint. Still, you get the idea.
