Sorry, didn't explain that very well - the magnet is NOT flexible (but you have a 20 ton press, soooo...
Seriously tho - I meant that the CHANNEL the magnets are glued into has RADIUSED edges (like if you rounded off the outer corners of a piece of small C channel - it will NOT work on a curved surface like a grader blade. Straight line cuts on FLAT material ONLY.
The Radiused edges are on the side that does NOT stick to the metal, and they are shaped almost EXACTLY the same as the PROFILE of the PM45 torch, so if you hold the torch fairly firmly against the side of the strip the torch will ride up just enough to leave a small gap between the torch tip and the metal - just enough to get away from the extra coefficient of friction between torch tip and metal.
Only way I know to cut curved metal is to use something that's flexible enough to conform to the curve, usually the convex side - cutting a large cylinder SQUARE is easiest, just make your "flexi-strip" straight on one side, then wrap it all the way around the pipe, overlap ends so they're flush on the cut side, and unless you pulled the strip so hard you deformed it, the result should be @ 90* to the length of the pipe.
Sorry for the confusion - if your "blade boo-boo" eats at you TOO much (and I've BEEN there

) you could always stand your blade on end over a piece of flat bar, tack that in place, WELD it in place, then hold your plaz against the blade surface itself and "trim" the excess flat bar away - that'd give you more plaz practice, more welding practice, more practice being VERY patient, and MAYBE even a nice straight edge on the end of your blade ...

...Steve