Here are a few simple things you can do to check out a used 10L:
Look the lathe over realy well. If it is as-removed from service, so much the better. You will see how the lathe was cared for. If a dealer got it, he may have prettied it up with glossy paint and Scotchbrite pads polishing the ways and machined surfaces. This may hide some of the problems, so you willhave to investigate a bit deeper as I will expalin, below. If the lathe looks abused, it probably has problems. If it looks used but reasonably cared for, you probably will be OK with it.
HEADSTOCK:
1. Make sure the lathe is in a heated building so the oil int he bearings is not so stiff as to mask problems.
2. With the flat belt to the headstock slacked ( release the tension lever), try to roll the headstock spindle by hand. It should kind of glide to a stop. It should stop smoothly with no jerkiness.
3. If you own a dial indicator reading in tenths of thousandths, or even an indicator reading in thoustandths, bring it along with you. Bring a means of holding the indicator off the toolpost of the lathe or even a magneitc base and a couple of bars to hold it off the bedway so the indicator contact tip is at 12:00 ont he spindle.
Brink a hardwood hammer handle with you as well. With these items you can check headstock spindle bearing adjustment. Put the indicator on the lathe so the contact tip is hitting the spindle on the undtreaded (register) portion at 12:00. Take the hammer handle and inert is into the spindle taper bore, and push down on the handle. This will push the spindle journal down hard against the bottom of the bearing. Zero the indicator, then pull up on the handle, trying to get about 75 lbs of force. Bearing clearacne measured on the indicator should be under 0.001". If it exceeds 0.001", then you may be looking at:
- a simple, routine clearance adjustment to the
bearing(s) by removing shims.
- bigger issues like a scored spindle journal
and a badly worn bearing.
There is no way to confirm either of these without a teardown, so you have to assess the rest of the lathe- where it was used, who owned it, how it appears for overall condition/care. If the lathe is being sold by a owner/user who can tell the tale of what he did to use/maintiant he lathe, you may be OK. If at an auction or dealer's, you may be taking more of a chance. I had this happen with my 10 L that I bought from Dave Sobel about 20 years ago. Got it home and together and discovered the spindle bearings were shot and spindle was ridged. Dave Sobel did make god on it, supplying me with brand new spindle bearings, oiler wicks, and shims as well as another spindle from a used 10L which had far better journals. Seeing alathe under power is OK, but it is not an absolute about condition of spindle bearings.
4. Check every gear you can see. Put the lathe in back gears and roll the headstock pulley over by hand for a few turns. check that the bull gear pin lets in and out easily and doesn;t need to be pried with a screwdriver, but does latch where it is positioned.
BEDWAYS:
There will be a square headed binder screw on the RH wing of the carriage. this clamps the carriage to the bed. Bring the carriage up close to the headstock and gently snug that binder screw with your fingers so you can stillmove the carriage with the handwheel. Crank the carriage back towards the tailstock. If the carriage binds on the bed so you can;t move it, you are looking at a saddled or worn set of bedways. How worn is hard to say. How will it affect accuracy ? Less than you might imagine unless you are doing toolroom or instrument type work. If the bedways are a disaster with deep scoring (grooving running along the line of the bedways)and deep nicks, then you have a lathe which has seen hard service and may have a lot of other worn parts and problems.
CROSS SLIDE and COMPOUND: Again, check the dovetails for wear and scoring visually. Crank the cross slide and compound thru their full range of travel. If you find drasticaly different amounts of force ont he cranks required to move the cross slide or compoundover their travel, then you are looking at badly worn dovetails and saddles. The rigidity and accuracy of the machine depend on these being good fits. A little difference in amount of force on the cranks is OK and expectable on a used lathe with some wear. If you find a really radical difference in what you have to put on the cranks over the run of the compound and cross slide, you have some serious wear which will take some re-scrapign. Simiarly, if things are this worn, the screws and nuts for the cross feed and compound are probably worn knife edged. About 0.020" backlash on the compound and cross feed screw of a used lathe should be about average. Look at the front of the compound for gashing wher it has crashed into a running chuck or workpiece. If the front of the compound really is gashed and beat, then the lathe has been abused and should be suspect.
APRON: Lock the carriage binder screw and try to crank the carriage. feel how much gear lash is present. Look at the shaft ends where they come thru the front wall of the apron and see if they are hopping due to excessive wear. Unlock the carraige, put the feed selector lever in its neutral position on the carriage and engage the half nuts. Move the carriage genttly up and back and see how tight the half nuts close on the lead screw threads. A little play is OK, but if things feel sloppy, the lathe will not be so good for fine threading work.
Crank the carriage the full travle and be sure the pinion on the carriage is engaging the rack on the underside of the front bedway. On worn lathes or lathes which have been abused and tinkered with, this can sometimes be an issue.
TAILSTOCK: Check the fit of the tailstock quill (the movable "spindle" in the tailstock) in the body of the tailstock. Crank out about 1 1/2" of quill, put your indicator on and lock the tailstock to the bed. Do not lock the tailstock quill into the tailsotck. Try to move the quill up and down by hand and see what the indicator shows. More than a thousandth or two and I would be leery.
Stick your finger into the tailstock female taper bore and feel it. Any scoring ? Any nicks ? A 10L should have a hardened and ground tapered bore, but if someone has spun a tapered shank in it or jammed in a shank against a steel chip and then spun the shank.... the taper if likely NG.
Having made this inspection, ask to see the lathe under power. Try running it in low speed/direct (pin ont he bull gear "in", back gear disengaged). Feel the spindle bearings for heating up. After a few minutes, move the belt to middle step and then to smallest step (highest speed) and check for bearingsheating up by feeling them. At low or mid speed, try running all the feeds, then at lowest speed with carriage at mid-bed, put in half nuts and try letting them in and out on a running lathe. Any problems in operation- any "catching" or slop in the mechanism to work the half nuts is going to be felt.
Ask to take a cut if possible. see what the lathe does when taking a cut. If you brought a mike, take a cut, mike it and then take another cut and see how close to accurate the cross feed and compound are. Take a roughing cut and see how the lathe behaves, then take a finishing cut of a very few thousandths at fine feed. If the lathe is worn and sloppy, the tool will kind of "float" along the cut and the surface finish will be good with some scratches or grab marks. Run the lathe in every mode you can, under power, and with a cut on it, you will learn a lot about it. Under power and taking a cut, you will see/feel how the feed clutch int he apron lets in and holds, and how the overall lathe behaves.
You will have to use your judgment and sense on the matter of buying a used lathe. A Southbend 10L is an incredibly forgiving machine which can take a mauling and keep on gettign the work out. Despite this, you do not need to buy a 10L which is hanging on to being a good running lathe by a thread, only to have something wear out or let go not long after you start using it in your shop. The fortunate thing is there are LOTS of used and even some aftermarket parts avaiable for the 10L lathes. They ARE machines a person can work on with manuals in English and plenty of us who own and know the 10L's to offer advice based on experience.