Very specific magnet hunt

February 22, 2025 11:33 AM

I'm in need of a magnet like this or this, which is to say 1) fairly powerful 2) roughly horseshoe shaped and 3) bench-mountable. Online search for such is proving difficult--is there some term for these I should be using? I've tried: horseshoe, alnico, demonstration, all yielding only a small, red model on Amazon and the like.
posted by working_objects to Science & Nature (6 answers total)

Searching for "Vintage Horseshoe Magnet" on eBay returned some promising results. Adding in "Radar" might give you some useful results too.

I think the need for these sort of magnets generally has gone away with the advent of the rare earth magnets, so I'm guessing you'll be finding mostly used.
posted by gregr at 11:50 AM on February 22

Go to Grainger.com and search for horseshoe magnet. They have several alnico magnets with a hole for mounting. Prices range from around $12 to $124
posted by LiverOdor at 11:55 AM on February 22 [1 favorite]

Response by poster: gregr's links were very helpful--it looks like what I want is a variable gap magnet; I do not need it to be old, necessarily.
posted by working_objects at 12:38 PM on February 22

You might want to look at what McMaster calls “bridge” magnets, too.
posted by btfreek at 4:18 PM on February 22

If what you're trying to achieve is a gap within which the magnetic field lines are strong and pretty much parallel, and you can't find a manufactured magnet that fits the bill, you might be able to construct one at low cost by using a hacksaw or cutoff wheel to cut the core from a discarded microwave oven transformer to the shape you need, then sticking a couple of button magnets on it where the active poles need to be. The core should do at least as good a job of containing, directing and connecting the field off the back of the buttons as a purpose-built magnet would.
posted by flabdablet at 9:32 AM on February 23

How about making one from a iron or steel C-clamp and a disc magnet on one or both clamp faces. Best if you could fix the swivel face with a weld, but glue should work.

Not knowing your application: A hard disc drive actuator has a magnet assembly with a small magnetic gap with parallel flux lines

Yet another thought is a surplus linear motor magnet assembly. The throat and gap are small but it has lots of length... great for an Eddy Current Demonstration
posted by tinker at 5:55 AM on February 24