[Brown and Sharpe surface grinder] one of the very top choices in SGs.)
Take your own diamond, a piece of mild steel, indicator, good like new (6 or 8" flat hone, dead flat bar, if possible a friend who is a grinder hand.to look at a machine under power ...
Tough to test a SG to tenths flatness. Buyimg from the owner/user is good so you can ask questions and hope for honesty.
To feel the chuck front long-edge and the cross-way edge to the right side edge with a known dead flat bar may tell the last chuck grind made flat.
Some may say grind feel or indicator feel a gage block set about the chuck...but if the chuck is belly or bow this check may feel good when the machine is a little off.
So perhaps these two test should be done.. know the chuck is dead flat from its last grind and then that moving under the chuck to find all places are the same..
Yes then to test the spindle with a sound rod and a test grind surface finish...using a hand spray bottle if the machine does not have coolant.
set the wheel on a wood block and test the down feel nut..a half hand-wheel turn means it need to be replaced.
Many a decent grinder will have considerable cross feed sloop and still be an ok/good grinder.
Give a side-way tug on wheel head to see/indicator it does not have a lot of side way sloop
Good to take a new/like new big fine hone to figure-8 hone the chuck ...Yes a Norton or better stone not a Harbor's frightfull stone. Yes ask before honing another mans chuck.
if the machine has been setting for a time then hand spin the spindle a number of times then jog start it a few times.( wait a bit between jogs so not to blow a fuse or kick out.
*look under to see oil flat ways have oil.. perhaps see scraping there. (if a scrape way machine)
*If you buy a surface grinder ->If you are not a grinder hand then don't be quick to grind the chuck..but practice grinding a big flat part to learn how to grind big stuff. Perhaps a 3/4 thick 6 x 10" mild steel plate.. such a plate is like a mini bench surface plate so will be very handy next to your grinder. Read up in how to grind a chuck/ what wheel and then do suck wet.
Once saw a big G&L that made a very good size part ..it having two chucks and the grind was a bow of about .002 low at each side of travel..Think is was about 96" travel..yes bought from a very good vendor so they paid for re-scraping/or helped pay for it (?). Two chucks spaced apart likely caused the wear.
*Good to post model and price.. like a lathe condition is important and to buy form a better market area is often worth the extra few bucks or transport costs,
Find here a good market area for SG prices.
detroit metro for sale "surface grinder" - craigslist