I bought a lot of NMTB30 tooling for $1,000, drove over 300 miles (each way) to get it and to my surprise the seller included an Erickson QC spindle which he'd swapped out of his Bridgeport for an R8. (Gunsmith, only does one-off jobs and already had an Ultra mill with R8.) Never mentioned that in the Craigslist ad or on the phone.
Got back home and got to looking at my old Acra and got to wondering if the spindle might fit. After figuring out the nut on it was left hand thread I had it out pretty quick. Hopefully I've found where the noise in the head is, the bottom bearings were real bad. Still working on the CNC refit, waiting on another VFD to replace the one that was going on the mill but ended up on my $400 junkyard rescue Monarch 12CK.
After comparing sizes, I figured all I needed to do was remove the bearings and install the left hand nut onto the BP spindle. Went in place just fine! Some of those Taiwan BP clones are real close copies.I'll be *extreme* happy if the noise is gone, won't have to take the VS drive apart.
Scored a $1,700 spindle and 47 assorted pieces of tooling for $1,000, gas money and one night in a motel.