Creating a Lightweight but Powerful Electromagnet

[Ainulph]

Yesterday I was using a riding a lawnmower and the bolt that held the float bowl fell off in deep grass. I looked for about 15 minutes when I seen a flash of lightning and I figured I better give up searching and start pushing this thing back to the house. This experience made me wish I had a huge magnet :)

Anyway, I want to go through with this just for the sake of entertainment and practice with electromagnetism. I want to build an electromagnet that can lift bolts and screws from the ground without bending over.

My main priorities are:

1. Device Works as Planned
2. Light Weight
3. Under $50 (Scavenging for used materials is a choice)

I'll post my current idea once I get some ideas, that way I can get some much more different(most likely much more efficient) design ideas. Thank you :)

P.S. I love the idea of science and engineering, but I don't have a proper education in either. One thing I'm wondering is what the proper way to measure magnetic attraction?

I'm assuming there is a huge oversight in my idea, feel free to point out if there is an issue even if you're forced to call me stupid.

 

[bassplayer142]

Although I can't answer this the best, I will say that a metal detector is another idea that would work. Depending on what you find more interesting or useful.

 

[Bob S]

A few years ago, a friend of mine was working on his car in the snow, and he dropped a critical screw for his distributor in a puddle. I had a big horseshoe magnet at home so I tied a string to it and dragged it through the puddle. Voila!
I wouldn't try this with an electromagnet, however.

 

[Integral]

I would think a fair sized rare Earth magnet would do the job better. There are so many compromises involved in making the electromagnet you need that the obvious and best solution is a permanent magnet.

 

[Danger]

Princess Auto used to carry what I thought was a pretty cool idea for a pick-up magnet. It was an aluminum box with a top-carry handle (like a bucket, but rigid). A powerful permanent magnet just fit inside the box, connected to a second handle inside of and a couple of inches below the first. In the 'rest' configuration, the magnet is nestled in the bottom of the box and will pick stuff up through the aluminum. When you want to drop it, just pull up on the internal handle to raise the magnet away from the load.
It should be easy to build a similar device onto the end of a long pole.