Making a simple punch and die

Gentlemen,

I'm about to make a suspension spring for a clock I have recently purchased out of spring steel, the spring will be 24.32mm long x 6mm wide and 0.06mm thick, it will have a hole 1.3mm dia and a rectangular hole 3.7mm long by 2mm wide.

The round hole will be drilled with a 1.3mm drill and I intend to punch the rectangular hole, I'm going to make two plates which are bolted together with the suspension spring trapped between the two, the two holes will be repeated through the two plates, my question is I intend to make a punch from silver steel to replicate the rectangular hole, heat treated will the silver steel be strong enough to do the job.

Thank you,

Martin P

You could make the punch from mild steel and it would work. Silver steel left soft also works. Do the round hole with a punch too. These little tools are usually only used once or twice so hardening is optional but to answer your original question yes silver steel heat treated is strong enough.

regards Martin

Yes, Martin's spot on. You only need to go to abrasion-resistant tool steels like BD3 if you're doing a pierce- or pierce-and-blank tool intended to output many thousands of components.

You will probably get away without making a die., Using a piece of hardwood end grain as an anvil will work. I have punched holes in stainless steel rulers this way and it works fine.

To amplify Norman's suggestion, if you use a punch and die, you need the two parts in precise alignment such as by a jig or the bolster system on a fly-press, so the punch goes through the die properly as it shears the spring blank.

Making a punch and die for a 1- off rectangular hole 3.7mm long by 2mm wide is a lot of work. Why not just drill a hole and use a small file to make the rectangle ?

Paul.