Tools to bevel a rod magnets

[marcfrom]

I want to make a bevel on a flat top rod magnets, what best tools/machine do I need?

Thanks

[David King]

marcfrom,
Best depends a lot of your resources but I bevel them using a portable electric drill and a cheap imported 6" grinder. I set it up so the the magnet and grinder are spinning in the same direction -where they hit they are moving in opposite directions. They come out looking pretty rough and the magnets wreck havoc on the face of the grind stone. Ideally you want a very light touch and that means the drill wants to have a low mass. A flexible shaft handpiece with a small 3 jaw chuck or collet chuck would be best. If the drill is heavy it will cause the magnet to bounce off the grinder and give you a very rough surface. If you have a steady hand you could spin the magnets in a wood dowel holder using your fingers and get excellent results.

[marcfrom]

It seem very difficult to be regular, have a right angle with this method.

Is there not a conical tool in which the object is rotated and bevel with the right angle?

[copperheadroads]

A Bench grinder with the rod magnet in a drill for about 1 second . at a 45 degree angle ............... doesn't get any easier than that .

[David King]

It seem very difficult to be regular, have a right angle with this method.

Is there not a conical tool in which the object is rotated and bevel with the right angle?

The problem is that AlNiCo is a very hard material and you would need to attack it with something like diamond encrusted cup with 45º sides. This tool may exist but it would be slow and would probably become consumed due to the iron content in the magnets which quickly binds with the carbon in the diamonds at fairly low temperatures (300º F) iirc. Beveling at home works out fine if you are just doing a few at a time. If you are needing lots of them then it's far better /cheaper to order them bevelled to your specifications from the factory.

[jack briggs]

hand drill and bench grinder

[Chuck H]

Well I'm not a pickup guy, but... I'm pretty handy at figuring out how to manage projects with what amounts to stone knives and bones IMHO copperhead and Jack have it right. I was going to suggest it but then they covered the method before I finished reading the thread. Put the magnet rod in the chuck and spin it against an abrasive (or a spinning abrasive wheel). Easy to see and monitor too It might be a good idea to wrap a strip of masking tape around the magnet rod before you chuck it just to minimize any potential chips.

[copperheadroads]

The grinding wheel in my bench grinder is rather coarse & leaves the magnets a tad rough ,i guess i could buy a finer grit wheel . but i use one of those rubber impregnated polishing wheel for the dremel .which is clamped in my vise while running so i do this method at once . About a second or so on the grinder then i turn & a few seconds on the polishing wheel while still chucked in the drill & spinning & it polishes the bevel .

[kayakerca]

A drill with a hand tightening friction chuck and a bench top sander (I use the disk not the belt). About 2 seconds at a 45° angle. Fast. Nice angle. Nice smooth finish. Very consistent results from rod magnet to rod magnet after you get the feel for it.

[big_teee]

I chuck the magnets in a drill.
I use a varible speed 5 inch hand grinder, with a fiber wheel.

[John_H]

I chuck them into the drill, and use a disk sander with 220 grit. Grinding wheels can be a little bit brutal.

[Chuck H]

IME you can do OK with courser wheels by using a light touch at the finish. You still need to fine polish, but a lighter touch at the end of the initial grinding reduces time on the finer finishing.

[marcfrom]

A drill with a hand tightening friction chuck and a bench top sander (I use the disk not the belt). About 2 seconds at a 45° angle. Fast. Nice angle. Nice smooth finish. Very consistent results from rod magnet to rod magnet after you get the feel for it.

It seems to be a good method, the bench top sander has a angle guide. But do you use a variable speed machine? What grid?

[kayakerca]

It seems to be a good method, the bench top sander has a angle guide. But do you use a variable speed machine? What grid?

My drill is variable speed, but I just set it the high range and run it full speed. The grit of the disk sander I can't remember off hand, but no, I don't adjust the table to a 45° angle I just eyeball it. With the drill whirling and the disk sander whirling it only takes a couple seconds tops to get the bevel finish I'm looking for. Once I'm in a bit of a groove, it takes maybe 5 - 10 seconds per rod magnet from start of one to start of the next.

[the great waldo]

I use a green grit wheel in a Dremel/proxxon held in a vice and spin the magnet in a battery drill.

Cheers

Andrew