I wound some stranded copper wire around an allen key about 15 windings and applied about 7 volts to it but it did absolutely nothing.

It may have been a steel allen key. Could that have been the problem? Or was the voltage too low?

 

I can almost guarantee it was a steel allen key. I've never run across any other kind. Steel is an alloy of iron and carbon, by the way. All room temperature steels are magnetic - except the austenitic stainless steels.

Try using a lot more windings.

(I trust the wire was insulated, yes?)

 

Yeah I guessed it was steel. Is there a big difference in flux between using an iron core or a steel one?

I stipped the insulation off the wire. Was that a mistake?

 

Yes, taking the insulation off the wire was a mistake. The turns just acted like a short, so no magnetic field got created.

Another thing that will help, besides using insulated wire - use a softer steel for the core. Something like a big nail will be more permeable than a hardened steel Allen key.

 

also try a lot more windings,
i remember long time ago when i made one i used a lot of windings and the book
suggested abt 200 turns.
use a thin enamelled wire (the one u wud find in small transformers)

 

With 7 windings you may experience magnetic atraction, but due to the excessive current. You will make a short for sure. Use wire until you have an appreciable DC resistance (20-50Ohm would do).