There was a related post and Jim B gave a good answer about extension cords, but wanted to ask a case-specific question.

I have a 240v jointer and just bought a 240v dust collector. Both 20 amps. I had a sub panel with 240v outlets installed but still need to use an extension cord for both.

Is a borg 12 gauge, 9’ oven extension cord (that is about 5’ too long for each machine) acceptable, or should I get one of the thick rubber bulk cords and build a shorter diy cord with the appropriate connectors?

If the latter, what gauge, and should they hang between the outlet and the machine so the don’t touch the concrete?