Removing the spindle

November 18, 2011

After getting a handle on why my backgear doesn't work I felt it was necessary to remove the spindle and do some maintenance work on that part of the lathe.

This turned out to be a lot of work and took all of a day. Now this should be a one hour job (I can say this after having tackled it), but if your lathe has been abused and screwed up like mine was, you may be in for what I was.

The basic drill is this:

Sounds easy, eh? Well, I'll explain what I did in some detail, along with some photos.

I didn't start taking pictures until I got into the "spindle pulling" part of the process. To get to this point, it was easy removing the collar and gear, but the woodruff key was really stuck. The thing to remember about these is that they have a round bottom. If you take a pin punch and hammer on one side it will rotate in the slot and the other side will come up. Eventually it is "easy" to grab it with pliers or vice-grips and pull it out. Then the next collar slides right off and you are faced with the next challenge: removing the dust cover without bending it horribly. The trick is to find something to pry with, I used the head of a proper sized round headed bolt.

The service note on removing the spindle says to use wood blocks between the bull gear and headstock and to hammer (with a wood block cushion) and drive the spindle to the right. On the advice of some people on the Atlas-Craftsman list, I rigged up a puller with a 2 foot piece of half inch threaded rod and some odds and ends I had laying around.

I just happened to have this big piece of steel tube with a square foot getting in my way, and it seems almost custom made for this job. Notice the wood plank being used to protect the ways. The other wood blocks support the puller. Notice the wood strips to protect the headstock from getting marred during the pulling process.

The game is to pull (or drive) the spindle to the right until this key emerges from under the bull gear. Then you drive it as far right as you can and (in my case) struggle till you manage to extract it. A miniature set of vice-grips was extremely valuable. The key will need to be driven much further to the right before it can be removed. If there is an advantage to the use of a puller, it is that you can very precisely move this key to just where you want and then fight with it. It would be hard to be precise with a big hammer. On the other hand, hammering requires no special tooling, just a hammer and block of wood.

Once the key is out, you would think your troubles are over. Mine were just starting. I continued pulling and suddenly everthing tightened up and I was cranking for all I was worth and worrying about breaking things. It took me a while to figure it out what was wrong, along with removing the puller many times and driving the spindle back the other way. The story turned out to be that the shaft had been badly marred by some dummy (some prior owner, not me) cranking down the setscrew in the pulley cluster. What I had to do was to drive the shaft back, pry the bullgear and pulley apart and carefully file on the shaft to clean up the burrs. Then I cleaned and oiled it liberally and things were OK.

I made this cute little horse-collar thinking that it might help avoid busting the bull gear by supporting it right alongside the shaft when I was driving it out. But I was wrong; the real trick was to file off the burrs. I'll save it in case I remove the spindle again someday.

Success! Here are all the pieces laid out in order and each is flopped over to the left. Notice the piece of 3/4 inch PVC. I found this to be ideal to drive out the spindle once I dealt with the burrs and didn't have outrageous forces to deal with. Once the spindle was flush with the left side bearing, I switched to using this and tapping with a medium ball peen hammer.

I was told by Scott Henion on the Atlas Craftsman group that if I looked at the bearing races, I could find out what year my lathe was put together. He was absoluely right. The left race shows the date 8-14-51. The right race shows the date 5-10-51. Amazingly, this lathe is 1 year older than I am!

And the above photo shows the mess I need to clean up. The fellow that had this lathe apparently used it for some woodworking (though he was a machinist), and I think he also kept a cat in his shop, because the lathe is covered with a greasy felt like fuzzy mess (a combination of oil, cat hair, and sawdust).

Note on the bearings

My bearings look to be in great shape, but here is some info for future reference. I am told that the Timken part number is quite standard and was used by Chrysler Corp in some automotive hub assembly, any AutoZone would carry them. Either bearing sells for about $20 these days, so it should be possible to get the pair for somewhat less than $40 if needed.

The hole down the center measures 0.80 inches at the chuck end, and 1.0 inches at the other (left) end.

Note on the belts

While the spindle is out is a fine time to consider replacing the belt. I took the belt down to my local hardware store, where the guy put it on one of the belt measuring gizmos and sold me a 4L330 generic cooler belt, which is completely wrong!. After getting it home and comparing it to the old belt it is clearly too big. Doing some research, I find that what I really want is a 4L310 (1/2 inch wide, 31 inch long). The belt on my lathe is labelled "Atlas Press S7126" and apparently is the genuine article that came with the lathe. 60 years old and it still looks fine! Rather than just replace it with a $4.00 made in Mexico, bargain price swamp cooler belt, I am tempted to go to Grainger Industrial Supply and buy a Dayton 4L310.

The other belt is not so critical (and much easier to replace). It is the belt from the motor to the intermediate pulley.

Analysis

The reason for removing the spindle was to get my backgear working. Apparently the prior owner never used the backgear and just tightened down the setscrew (intended only to be an oil fill plug) on the pulley cluster. The bushings were quite dry, but seem in good shape and there is quite a cavity to hold oil between the bushings inside the pulley cluster. The small gear right of the pulley cluster is intended to be mated to the pulleys all of the time. The pulley cluster and gear run free of the spindle and should only be coupled via the pin on the bullgear when in direct drive.
Have any comments? Questions? Drop me a line!

Tom's home page / tom@mmto.org