Beware that there is an obsolete line of plugs and sockets called NEMA 10, with angled pins. These do not have a safety ground and are fairly dangerous. These were banned in 1965 except for dryers and ranges (hobs) and were banned for those as well in 1996. However there are many legacy installations and the socket is still sold widely to fools, because Freedom (tm) lol.
Here are the 30-amp versions of each. Green you are familiar with. Blacks are your 240V, white is useless neutral.
You can use either of the other two families.
NEMA 6 does not provide neutral, which you do not need anyway. They come in NEMA 6-15, 6-20, 6-30 and 6-50.
You can also use the NEMA 14 family of plugs (hot-hot-neutral-ground) which come in 14-30 and 14-50.
Since our plugs do not have fuses, we size the circuit breaker closely to the tool's demands (not like Australia). We also use different plug shapes to prevent high-current appliances from plugging into low-current circuits. Take the running amps of the tool (disregard startup/LRA amps), multiply by 125%, and you want the next size up for that. So
0-12 amps uses NEMA 6-15
12-16A uses NEMA 6-20
16-24A uses NEMA 6-30 or 14-30
24-40A uses NEMA 6-50 or 14-50
Here are the smaller NEMA 6 sockets on the right, which use the same junction boxes and wires as our 120V sockets on the left. Note how our 20A sockets also accept 15A plugs, hence the T-shaped slots. That is a one-time exception for that size only.
If you want to plug a NEMA 6-15 plug into a NEMA 14-30 socket, they make adapters for that, and the adapters have 15A fuses in them as required by UL. We do not trust manufacturer self-certification (CE). Anything sold at retail in America must be certified to national standards (written by UL) by an independent testing lab - typically UL but others are also certified - CSA, ETL, BSI, TÜV etc.
Anything sold mail order bypasses our consumer protections, and Amazon Marketplace (like eBay, but blended in with Amazon search results) is the worst offender. They have made themselves a conduit for sneaking these dangerous goods around Customs. in fact 99% of the items listed on Amazon are dangerous cheap Cheese junk from sellers with no assets to sue.