What is the way to check the bed wear,
-Bed wear is one of those things that can be checked at the headstock only or over the entire bed length. Checking over the entire bed length isn't easily accomplished with any real accuracy and most people will concern themselves with where most of the operations take place, near the headstock. Even with some wear most will simply compensate for the wear in the bed, that's what I did when using an old lathe. The simplest way for checking for wear on the bed is the finger/thumb nail test, dragging your nail across the "V" and flat part of the bed ways feeling for ridges that get wear from the years of sliding the carriage to/away from the headstock. A dial indicator can also be used to determine if the apron rocks in/out relative to the bed when changing directions. This can be partially compensated for with the carriage/saddle lock so make sure it's not partially on. Cross slide and compound should be checked for wear by the amount of backlash on the dials. Go one direction to get movement, then very gently reverse the direction and feel for how much "slop" there is before it starts to reverse motion. Setting "zero" on the dials gives you numbers to quantify the backlash in the lead screw/nut on cross and compound. There are also dovetails in the cross and compound slides with adjustable gibs to take-up wear in the slides themselves but we needn't go into that unless you have the lathe.
also if it only has one chuck is it easy to get one for desent price?
-That will depend upon what you consider a decent price and what configuration the spindle nose is. Sheldon had many options specified by the buyer so each lathe is somewhat individual. There was the collar, threaded nose, and cam-lock system of mounting a chuck. The collar was a PITA, the threaded nose meant you'd either have to have a threaded mount type of chuck or an adaptor plate. These two mounting systems are also prone to over-tightening and can be difficult to unthread when rust bonds everything together. This is what often leads to engaging the back/bull gear and stressing that gear to the point of damage/fracturing of the gear when attempting to remove the chuck. Contact me for a safer method than the wrench-and-hammer method. The cam-lock was and is the preferred mounting because it was easier to mount/dismount, considered safer by some, more consistent by some, and is more readily available today. I can't tell from the photos what you have as there's no photo showing the area between the chuck and headstock. I'll include a link below that documents a LOT of information regarding Sheldon lathes. For instance, the double lever QC gearbox and drive type indicated that this one is a later model. The "T" prefix to the stamped model number suggests either the drive type, a taper attachment, or the presence of tapered bearings vs plain bearings in the headstock. A lot of information about any particular lathe was only found on the build sheet paperwork. There were so many different options offered that the original build sheet was the only reliable source, without it you have to examine the lathe itself for configurations/options. The link below has all this info and several good photos, including one with a paint scheme that looks similar to your candidate.
-If the tooling is minimal I would have to ask what you plan on using it for. You stated that it was probably general type work but I'll hope that long shafts isn't one of them if there's no steady or follower rest. Unsupported work after a certain length becomes very vibration prone and difficult to machine accurately. The bed shows a number of dings/dents in the bed by your photo but that's to be expected with an older lathe, very careful selective stoning can improve things. I have a soft spot for the Monarch but would probably still opt for the Sheldon if things check out, the Monarch doesn't look like it was cared for very well.
I read that if the spindle bearing are bad replacement ones are like $400.
-Spindle bearings are a critical part of ANY machine whether it's a lathe, milling machine, or surface grinder. You'll want to listen for excess noise while it's running, crunchy or cyclic sounds are real bad. Excessive heat at the headstock isn't a good sign either. Slop in plain bearings can be determined by using a 2x4 under the chuck and GENTLY prying up while having an indicator on the chuck to check for deflection. Some owners would be horrified to see this but if done gently it's no big deal. Replacing bearings in the headstock will have very defined methods and I wouldn't suggest replacing them unless you truly know what you're doing so pay attention when evaluating any machine. If you think $400 is expensive you should price out what spindle bearings for a surface grinder are going for, even the bearing grease cost more than a nice restaurant dinner. I'd consider $400 to be a bargain for what they do. Metalworking machinery, tooling, or measuring instruments are expensive. If it's not expensive it's either used or not very good quality, either step up or step aside.
Sheldon were based, originally, at 4258 North Knox Avenue, Chicago, USA, and made a range of machine tools including millers, shapers and lathes using their own as well as
www.lathes.co.uk