number of teeth for soft metal?

I was thought the harder the metal the smaller the teeth. But no, aluminum requires smaller teeth than steel.

Hardened steel, like that found in some old bed frames, wears out my blades and drill bits very fast. Any suggestions?

randofo6 months ago

I don't think your problem is teeth count, but how you are trying to cut it. After some research, I found this:

It appears to be hardened and cut slowly through more of an abrasive process like an angle grinder. That should do it.

If you happen to have a dremel (or similar), you can get a reinforced cut off wheel to go right through it. That is the way I would go for something small like a bed frame.