On my Chinese vise. I bought it on sale from BusyBee (Canadian Grizzly)a number of years back to use on the drill press. When I opened the box I realized it was too heavy and awkward, so it stayed in the box until that someday mill. The mill/drill came with a nice Japanese 5" conventional milling vise, so it stayed in the box until I got the shaper.
-the swivel plate was uneven and out of parallel, it was trued?? on a shaper
- the down wedging ball was very rough and so was the socket it fit into
- one of the jaws varies .007 in thickness ,which I haven't trued yet.
- and jaw heights were different
-the screw isn't an acme ,rather just a metric? thread
I think I paid $79.99 but that was a while back. The vise bed itself is parallel to the bottom, within a thou or so. Which I would call good.
I drilled the swivel plate to use as an adapter and slotted the vise for when I just use it . They just fit. But they eat height.
A shaper vise is low and wide, with the screw being anchored in the stationary jaw, unlike a milling machine vise. They also use the table as the swivel plate.