I don't have the one for the mini lathe, but I do have one that
someone made me for a South Bend 9A (which I no longer have)
It is mostly the same, just about 1/4" short so it would need to
be shimmed. Not open on the sides like the WC rest, this one
is a full circle. It's brand new, just a bit dusty. But if you ever
need to put it on a South Bend, it already has the notch for the
ways. Might be more than you're looking for, though.
Whichever you do, look into changing out those metal rollers
for something softer that won't mar the wood. Roller skate
wheels would be idea, but to big for that rest.. something along
those lines would work great though.
