Magnets

[walhondingnashua]

So this is going to be an odd question but there is a large pool of people here with many backgrounds.

I am looking for magnets that have a measurable amount of force or strength. Meaning, it take X amount of force to make this magnet break lose. Is this a realistic thing or am I just not going to find something like this?

 

[Whitenuckler]

So this is going to be an odd question but there is a large pool of people here with many backgrounds.

I am looking for magnets that have a measurable amount of force or strength. Meaning, it take X amount of force to make this magnet break lose. Is this a realistic thing or am I just not going to find something like this?

I think it would depend also on the material the magnet is placed on. Can you do some testing using some sort of strain gauge hooked up to a meter that records maximum? If you need just an estimate, you could use a fish scale and record it on your phone to see how many pounds force it took.

 

[Turbo89]

There’s online calculators for this type of thing, but that particular calculation is difficult and is often verified with testing.

Things that matter:
- magnet grade and type
- material you’re sticking too, and it’s size.
- how the magnet held onto the thing you’re trying to hold in place and the magnetic circuit
- temperature ( a lot of magnets don’t like elevated temperatures).
- load direction. Think of your fridge magnets, they’re hard to pull off and easy to slide off.

All that aside, McMaster Carr and other places sell standard magnets with “force ratings”. If you’re in that range, you’re probably ok. When in doubt try to build it and test it… or nerd out and learn how to analyze it.

 

[EbS-P]

how much are you lifting 1? 10? 100? 1000 pounds?

 

[walhondingnashua]

Roughly intervals of 10 up to maybe 50 pounds.

 

[Whitenuckler]

Roughly intervals of 10 up to maybe 50 pounds.

Do you need to release the object or is it semi-permanent? If you need to release you should look at an electro magnet setup.

 

[walhondingnashua]

Yes we want a release at the known weight. Adding electricity won't be an option.

Basically we want someone to be able to pull on the magnet until the magnet lets go.

 

[EbS-P]

Yes we want a release at the known weight. Adding electricity won't be an option.

Basically we want someone to be able to pull on the magnet until the magnet lets go.

I would just use multiple magnets secured to a pulling block. Find the right number. I would tend for more less strong ones so I could attach them in a way they don’t slam and break.

 

[Whitenuckler]

Yes we want a release at the known weight. Adding electricity won't be an option.

Basically we want someone to be able to pull on the magnet until the magnet lets go.

OK, yes then buy some magnets based on the spec lb pull and get the highest lb rating that you can easily release. If it attached with a rope it might be hard as that would be a straight pull.

 

[EbS-P]

The other way to adjust pull strength it to make a holder that you can adjust how far away the magnets are from the surface.

 

[walhondingnashua]

Thanks folks. All great information. This is going to be a big trial and error project for the trainer and I this summer. My son is going to be the test subject lol.