I've confirmed that I have a brand new, never installed Cross Feed Screw & Bronze nut for a Jones and Shipman 540 surface grinder but can't remember who was looking for one !
I assume that this one is Imperial but I've not measured it yet. Open to offers - I know it was a small fortune at the time. I bought it when I got my 540 years ago, and although I have play in mine it's not bad enough to go to the trouble of changing it, especially as I have a Newall DRO on it.