Hello, im going to create a crane, arm device that can pick up metallic objects using a magnet, then with a press of a button, or switch it turns off. i know you need a soft iron core pole thing for the magnet. i also know kinda how to magnetize a piece of iron but in afraid i am thinking along the wrong lines. so how exactly shall i do it. (the magnet part please) also is there a change i would be able to change the strength with a variable resistor or something?? please help.

 

I hope you realize, a magnet will only pick up objects containing iron.

 

yea, all ferrous metals will be picked up I get that Much LOL

 

We are talking toy size her I guess

 

Yes, each are will be about a foot, 2 arms and a 4-5 inches base to house the components motors switch etc.

 

You are after electromagnets, the simplest one is a coil of wire around a nail; the more coils the stronger the magnet. They require DC and a decent amount of current if I remember rightly.

 

You are after electromagnets, the simplest one is a coil of wire around a nail; the more coils the stronger the magnet. They require DC and a decent amount of current if I remember rightly.

No I would not recommend using the nail approach. In this thread posting 5.
http://forum.allaboutcircuits.com/showthread.php?p=396877#post396877
One of our more competent members SgtWookie, suggest taking the core out of a mechanical relay. And I think you will be far better of with that kind of solution. Will you be able to get some solder work done either by you or some helper. How will you power the crane electro magnet?

 

No I would not recommend using the nail approach. In this thread posting 5.
http://forum.allaboutcircuits.com/showthread.php?p=396877#post396877
One of our more competent members SgtWookie, suggest taking the core out of a mechanical relay. And I think you will be far better of with that kind of solution. Will you be able to get some solder work done either by you or some helper. How will you power the crane electro magnet?

or just use the coil out of a relay. You could 'diffuse' the field by adhering a small ferrous disc to one end.

I used to work on the North American make of diesel electric rail cranes. I'm guessing that those were probably 5ton mags that the fellows would cast out after a rotating the boom some distance. More than once came in to find a whole rig lying on it's side.

 

or just use the coil out of a relay. You could 'diffuse' the field by adhering a small ferrous disc to one end

It was just what i ment. But I see now that i was not as clear as I should have been. My bad

 

I got your point, and completely agree. Winding coils can be exciting when it finally works, but really it's a lot of tedious work when you can find one so easily, ready-made. An old tape-based answering machine will often have several solenoids in it. Not big ones, though. A DIYer has a challenge to get enough length of a thin enough wire to limit the current while getting a decently high number of turns. Fifty turns of fat copper wire around a nail works, but draws a huge current for not much field. The optimum solenoid coil is nearly square in cross section; it's almost as fat as it is long.