I have almost the exact same lathe, except mine is not a gap bed. Yours is made to turn slightly larger bowls on the bed side, whereas mine has a rest on the outboard side for turning large diameters. My model was manufactured in 1950. Unless someone put some goofy pulley system on yours in the past, or Iím not reading your post correctly, Walker Turner lathes use a pretty beefy drive belt. I donít recall the drive belt being a quarter inch in any dimension.
Most belts are designed so the top of the belt rides flush with the top of a V groove pulley. The narrow dimension at the bottom of the valley is of no consequence. If a belt top runs sunken down into the groove, it is not correct and has probably been replaced with the wrong thing at one time or another. I'm not at home right now to look at specifics, so I cannot be sure of the cross section of our brand. But since you have an existing belt, all you need to do is measure the TOP width and the height of your current belt, then compare it to any V belt cross section chart on Google or Bing images (look up ďV-Belt Cross Section DimensionsĒ). Thatís the belt you need. Length is measured the same way; on the top cord of the belt. Or get a set of these to have forever:
As far as replacement goes, it is not always a simple process. The spindle shaft on these old machines is usually both dirty and rusty, and the spindle must slide through both bearings and the four-step pulley at the same time. If you can get the spindle clean and smoothed, youíre in business. Fortunately, you will only do this once since, unless you run it 24-7, a belt will last close to a lifetime. So, if you decide to go for itÖ
First loosen the (4) setscrews and remove the collar from the outboard side of the spindle. Then loosen the (2) pulley setscrews. A good indicator if the spindle is going to slide easily is to try to spin the pulley on the spindle after you loosen everything. If you canít turn it, it wonít slide either (Note: Iíve seen double setscrews on a couple of my older machine pullies. Occasionally they must have installed a second screw in the hole to retain the first one! Be sure you have actually released the setscrew that is securing the pulley to the spindle). Regardless of how hard you must go about it, drive the spindle out left to right. Catch the pulley and spindle as they become free to avoid dinging them.
Bearings removal is pretty easy to decipher- after the spindle is out remove the (6) cap bolts (three over each bearing), remove the caps and pull the bearings out. But again, remember that those bearings have been in there for a very long time. They probably wonít just fall out of their housings. Youíll more than likely need a puller.
Installation is simply the reverse of removal, though you want to make real sure that every trace or rust is gone from the spindle, and all setscrew gouges are filed clean to allow a smooth sliding spindle. The spindle should slide home by hand without a hammer needed. I used a light coat of Never-Seize on the spindle before re-installation.
Also, if you do decide to change bearings (and why not, they are old as Moses and you have it this far apart), I suggest buying permanently lubricated units. Otherwise you will need to feed the lubricators with 30 weight oil periodically, and it WILL seep out the ends and make a mess.
If the bearings are good, Iíd give the link belt another shot. Whatís to lose?
These old machines are just about bullet proof. Good old solid cast iron throughout. No plastic or pot metal here! Once you get it like you want it, there is no reason it canít last a hundred more years.