My second Hardinge lathe, bought around 1980, was like yours, but had the original wood top and pipe leg bench. Mine dated to 1936 and the serial number was on the steel plate covering the brake linkage adjustment port on the rear of the headstock. Your tailstock is a later 1940's model which is a better design than the original.
I took the spindle out and soon regretted it. I could not get it out without destroying the cork washer-shaped seals around the bearings. Making new cork washers did not go well. Anyway, leave the spindle and bearings alone if they are at all still good enough to use. It is very common on these old Hardinge enclosed head lathes to find a previous owner installed link-type V-belts. That type of belt can be installed without removing the spindle.
Tony has a good cross section of the 1936-1939 headstock. Cataract Lathes
Here are pictures of my 1936 lathe, which I no longer own, and the cross section from Tony's site. The pipe leg bench is excellent, but was probably cheaper than the desk-bench. Too bad the back of your desk got that big opening cut out.
I've had an enclosed headstock like this apart before and what Larry says about leaving the spindle and bearings alone if they are at all good enough to use is surely true. Those cork washer seals are usually in bad shape and easily destroyed in taking the spindle out. I've made new ones like Larry and had the same result. Getting the fit between them and the rotating parts is so picky I gave up. It was either too tight and made the spindle get quite hot or they leaked. I even tried increasing the ID of hole in the 1/4" thick cork seals by .001" at a time and couldn't get them to work the way I wanted. Imagine doing that on your mill.
I was rebuilding the headstock of my friend's BB4 mill, which uses the same internal design as this headstock. The previous owner had replaced the front bearings with a pair of sealed bearings, so I just removed the front cork seal, which wasn't needed since that set of bearings didn't need oiling. Plus the front cork seals were destroyed. That previous owner had also lost the metal snap ring that holds the cork seal at the outside of the rear bearing, so I made another snap ring along with the seal. When I couldn't get the rear seals to work without heating up the spindle, I ended up making a set of shields for the open rear bearing. It luckily lent itself to that and worked out fine. I filled it about 1/4 with grease and then the entire headstock had grease filled and sealed bearings. It's running up to 3000 or 4000 RPM just fine.
Now to what I am really writing about - using a link belt to drive the spindle. I made a drive system for the BB4 mill and used a 3/8" wide link belt to drive the spindle. I only used a single belt because I wanted to use all three pulley grooves for different speeds. The single belt was OK since the mill wasn't going to do heavy work. The link belt worked really well. And it's the only way to go with an enclosed headstock - you don't want to be pulling the spindle every time you change out a belt. If you're wondering why the pulley that connects to the spindle has the steps arranged as large, small, large, I don't remember why I made it that way but I must have had a reason!
I don't know how well 3 link belts will work side by side. If not, the maybe just 2, spaced at the 2 far grooves. And I don't know how the lengths of 3 separate link belts will turn out to be the same. It may work OK since the tension will tend to stretch them to the same distance, close enough.
How did you take the spindle and bearing out?
When I removed the oil caps the wicks were rotten, so I have to see what the bearing look like, replace the wicks and install 3 matching belts.
I made a special wrench to unscrew the nut from the left end of the spindle. The wrench is a steel tube with two steel dowel pins in one end to fit the holes in the nut. The tube has a hole through the wall for a hook pin spanner to apply torque. I have no respect for people who use a hammer and punch to work on this type nut. They leave proof of their incompetence behind.
Oil wicks should be 100% natural wool felt or yarn with no dye. They should last for 100 years or more.
Where would you put three matching belts? My lathe and the cross section drawing used two.
Ser. No. 59-14086 was built late in 1939, probably in December, which means the three belt drive was a late development. It could have simply been to make the belts last longer, since they are so hard to replace.
Where would you put three matching belts? My lathe and the cross section drawing used two. Larry[/QUOTE said:Here is a picture of the spindle and pulley in the BB4 mill, which is the same as the one in this lathe except for the nose. It doesn't come out this in this configuration, though, because the second seal from the front bears on the area between the bearings and the first pulley groove. The spindle itself has to slide out of the pulley. You have to keep the pulley inside by engaging the "stop pin" on the side of the headstock to hold the pulley in place while pushing the spindle out of the front. Of course, you have to remove the front bearing retainer. Then you have to "surgically" remove the snap rings and cork seals that bear on each end of the pulley before it can be removed. A set of long snap ring pliers will be handy!
The way the spindle looks when it is removed - pushed out of the front. There is a long key that either stays in the spindle or the pulley, I don't remember which. The rear bearing stays in place and is removed out of the back. I used a long piece of threaded rod and a plate that rested against three long rods threaded into the bearing retainer holes in the headstock to pull the spindle out the front. I also gave the rear of the spindle a few light taps with a dead blow hammer (plastic face) to help it along. As the spindle assembly came out, the bearing retainer slid along the three long rods. When I got it out far enough, I could just hit it with my hand (in a glove) at the far end to move it.
And a picture of all the components except the cork seals and steel snap ring seal retainers. I did include one of the snap rings in the picture for some reason, though.
I forgot to mention that the mill headstock I was working on, and showed pictures of, didn't have the brake unit in it. The lathe headstock I have did, and the first thing you have to do is unscrew the little cap on top of the headstock that has the brake spring under it and remove the spring so the brake isn't pushing on the pulley.
Since you're using the original bearings, be alert for loss of preload in the stack, caused by wear. This will show as axial play once the spindle is assembled.
Any play at all means the preload in the bearing pair has 'gone away' and ideally those bearings should be replaced. You really cannot tell this has happened by visual inspecting the bearings.