Why rating capacity is different between hand and machine torch?

[Beetman05]

I am thinking of buying a Hypertherm powermax 600, the machine is rated at 5/8" maximum capacity with hand torch but with machine torch drops to 1/4" would like to cut 3/8" if I went with cnc table and use machine torch will this be a problem don't understand why the difference between the hand and machine torch capacity? Does anybody use machine torch with 3/8 thick steel with good results or do I need to go to a bigger model.

Garry

[Al_The_Man]

Usually to get the same capacity with a higher duty cycle, which a machine torch generally has, machine torches are water cooled over a certain size.
Al.

[DSL PWR]

What Al said and...

with a hand torch you can come into the plate, and\or angle the head slightly to get better piercing. A plasma in a machine application can't tilt the head, so the pierce capacity is lower. If you start the cut in a hole (no piercing required), and go slow you should be able to cut 3\8. Just remember the cut quality will suffer a bit.