This adapter fits the Oneway Live center. The internal thread is 3/4inch x 10 TPI and the external thread is M33 x 3.5 (Metric). This thread fits into the most common four claws and clamping plates. This makes it possible to mount the four claw on the counter Center on a Oneway lathe.
This adapter is of course also used on lathes that have a 3/4 x 10 TPI axis. It is then possible to assemble all M33x3, 5 (standard in Europe) accessories on the lathe.