What are these drill bits called?

[KatieandDad]

I've never had to sharpen any of mine. I only cut alluminium and very thin plate steel.

They are over 10 years old now and working fine.

[simon7000]

Originally Posted by KatieandDad

I've never had to sharpen any of mine. I only cut alluminium and very thin plate steel.

They are over 10 years old now and working fine.

Try it and see if you notice a difference. Aluminum sometimes leaves a residue on the edges that makes punching slightly harder. Steel does dull punches, but it really depends on thickness.

Some of my machine tool punches are expected to be able to punch 300,000 holes before needing to be replaced. I am on my third set for some!