Which magnet would I need?
Which magnet would I need?
(OP)
Hello everyone, I’m designing something that will rotate and it needs to grab onto ferrous material that it rolls over. (Picture a typical rolling pin who’s function is to gather iron filings.). What shape magnet would one use to achieve this idea? The magnets would need to be set so that they attract iron onto the surface of a plastic or brass cylindrical “rolling pin”, let’s say about 2” diameter and 14” long.
For further clarification of what I’m after, I would expect the magnets to adhere (be glued) to the inner surface of the plastic, or brass tube. Or, most likely, adhere to the outer surface of a lesser diameter plastic tube that slides inside of the outer tube. When rolled across a table covered in iron filings, the outer surface collects iron filings. It one were to pull out the inner cylinder with the magnets glued to it, the iron filings would fall off of the outer cylinder.
Thanks for your help,
Dudley
For further clarification of what I’m after, I would expect the magnets to adhere (be glued) to the inner surface of the plastic, or brass tube. Or, most likely, adhere to the outer surface of a lesser diameter plastic tube that slides inside of the outer tube. When rolled across a table covered in iron filings, the outer surface collects iron filings. It one were to pull out the inner cylinder with the magnets glued to it, the iron filings would fall off of the outer cylinder.
Thanks for your help,
Dudley






RE: Which magnet would I need?
Machine a plastic or aluminum (or whatever) cylinder, and spot drill holes round the perimeter. Glue your magnets in, then sleeve with brass/plastic tube/sheet.
How many magnets and what pattern depends on how much magnetic power you need to pick up whatever it is you're trying to pick up.
RE: Which magnet would I need?
Dudley
RE: Which magnet would I need?
See the animation there.
Trivia: I find magnets interesting, and have removed my fair share from speakers through the years. Well, long ago, when I was young, I was working for a company that did demolition. One of the things that wound up in my truck was a magnetic roller, roughly 14" diameter by 24" long, as I recall. You could stand back from that thing 20', lob a crescent wrench over there and twang! It's stuck. (but could be pulled off, it wasn't THAT powerful.) Anyway, I was planning to open that thing up and remove the magnets, but simply couldn't find any way to open it or disassemble it, and don't know how it was put together. The end caps were cast aluminum, there was about a 2" shaft, but no other bolts or tabs or rings or anything to undo to break into it. Alas.
RE: Which magnet would I need?
RE: Which magnet would I need?
B.E.
You are judged not by what you know, but by what you can do.
RE: Which magnet would I need?
At any rate, I went ahead and ordered a slew of those cylindrical neodymium magnets and will do the fabrication as jgKRI suggested. That design is what I had in mind, I just wasn’t sure about which magnet to choose.
Thanks everyone!!
RE: Which magnet would I need?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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