testing used surface grinder

HI
Im looking at an old Brown and Sharpe surface grinder

Ive read the posts on how to test a grinder to see if its worn out but honestly, a lot of the info was either conflicting or just didn't sink into my thick skull. Im not a machinist by trade, just a hobbist so im self teaching


I originally thought of grinding one side of a 1 inch square bar, then the opposite side and mic ing the length.
Ive now read that this wouldn't be very good . Next thought was use two 1 inch square bars, grind one side of each and lay them together and check for gaps.

Am I heading in the right direction or is there a simplier way?
thank you

[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

Thank you for the information
Seller says its a Brown and Sharpe AX186/1 model
Asking price is $750

I don't know all the models but $750 seems a good price. Is it from owner/user or machine seller?
Under power? Good to see it run because rebuilding a spindle is costly. In good condition will last for a very long time. Needing repairs perhaps a dead horse.

I passed on one last year not under power and needing a belt for $100...a basket case machine yes. so could have had other issued.

OT: I'm just back from Blind River/lake Matinenda ice fishing trip..Broke my snow machine...Dar.n

I just spoke with the seller and he says its a R1 from the 40's. Original motor is burned out, so it cant be seen working
Im thinking I should pass on this one...unless it was for scrap price

if it looked good and ran manually perhaps $200 value IMHO..Likely another $200 to move it.

Motorize spindle or belts drive/ you can use alternate motor if belts drive/I have a motorized spindle motor I would give for 300 or so.

But yes to pass on this one.

Two quick notes on old surface grinders.
First, it is quite common that the bottom of the chuck would rust, pushing the chuck off-level: chuck needs to be removed and cleaned before operations and any test-grinding done using the chuck could give very misleading results.
Second, if the machine is not under power, you can still test the flatness of the X axis with a parallel at least as long as the travel of the table, two blocks on which to rest the parallel and a test indicator.

Plot the readings every inch or two of the table movement and verify that they're on a straight line: any deflection from flat is the actual localized wear and it will translate on any grould part.

Paolo

Thanks Paola, the heads up about the rust tip is a good one

Im worried about spindle condition and if something that old is repairable

Or if a needed part can be found..