I lost an m7 set screw. What do I do?


M7 set screws are impossible to find in hardware stores. So instead of paying out the wazoo for a single screw online, is like to find another way to safely hook up the power cable on my amp. (I found an m7 bolt in lowesb afraid it'll arc and cause a fire if I use that)

Is there a way to solder this 4 gauge wire to the amp?

Its for a class D monoblock subwoofer amplifier in my car.
thirdeyethirdear
Thanks for the advice! I ordered a good kit for this amp. The only thing missing was that one set screw. When I wire it this week, ill use the bold (unless I can find a new m7 set screw) to the ground terminal.

Its a jbl BP1200.1 mono amp (for car audio). I feel confident in my skills here, just wanted to get some extra input.
Thanks
Worst case scenario, would be to cut the bolt you have to the proper length and cut a slot in one end that would allow a screwdriver tip to fit. Do you have a Dremel tool? That would make life easier.
I found metric screws (especially set screws) at the "big box" stores are located in the hardware department in the "specialty" drawers. Just ask someone for what you’re looking for.
That's a really good idea. I thought about cutting the bolt. Ill see if my old dremel is in the garage. 

And ill keep my feelets out for an original in the mean time

(Fyi bdp24, my ace has metric too. But the m7 set screw is "antiquated" says the ace rep)
Thanks to all for responding.
I made my own m7 screws. I took Theo's advice, and I cut the hex heads off of some m7 bolts.  I put each screw in a power drill, then used my hack saw to get through each screw. 10 minute job.
Next step it to cut some flat head slots, and file off the one bur on each screw.

Thanks Theo.