As expected, as I’ve been using my lathe, I’ve run into some issues. The first issue I mentioned in my last post. During drilling with the tail stock, the spindle would seize in the conical bearings. My Hendey employs two conical bearings for the spindle to run on. The face of the front bearing runs against a spacer that presses against a flange on the spindle. Over time this spacer and the bearings will wear. As a result the spindle can contact the bearings instead of riding on a cushion of oil. Shims can be added to the spacer (or a new spacer made) to maintain the correct spacing between the bearing and spindle. Thanks to the folks at Practical Machinist I knew why I was having this issue and expected to run into it.
The first thing I had to do was get the back plate off the threaded nose of the spindle. To do this I removed the chuck from the adapter plate. The adapter plate is held on with three screws with recessed hexes. Unfortunately, the screws had somehow been damaged to the point where I couldn’t remove them with a hex key. I ended up drilling out the heads enough to where I could remove them with a screw extractor.
With the adapter plate removed, I had access to the back plate. Though I’d tried to get this off before, I was able to finally. After seeing the idea in a post on Practical Machinist, I wedged a tapered piece of wood under the bull gear to immobilize the spindle. Then, with a piece of mild steel and a hammer, I struck the shoulder of the cut outs on the back plate. After a hand full of moderate blows the back plate broke loose and I breathed a sigh of relief.
Here’s the nose of the spindle. It looks to be in great shape.
From posts on Practical Machinist, I was able to determine what size shim for the spindle was required. The method to determine the proper spacing first requires you to remove the spindle, wipe the oil from the spindle and bearings. Then, remove the stock spacer and reinsert the spindle using firm hand pressure to seat it. Next, measure the spacing between the front of the bearing and the inside of the spindle’s flange. For my lathe the space was 0.129″.
Next, you need to measure your spacer, as I’m doing in the picture below, and subtract this from the gap size. Then add about 0.006″. I say about because there was a small range I saw discussed and this was in the middle. The 0.006″ provides the correct spacing for the bearings. Doing the math says I needed a 0.011″ shim.
I ordered some 0.012″ shim stock from McMaster and went to visit my friend Gill to cut it out on his Bridgeport. Try as we might, we were not successful. In the end, I picked up a piece of 0.01″ thick brass locally which we were able to successfully cut. I didn’t get a picture of the shim because my camera was dead but you can see it installed in the picture below. Brass will probably wear faster than if I’d used steel but I think it will last a long while under the light use it’ll see from me.
Once I had the shim taken care of, I reinstalled the chuck. To replace the screws I had to drill out, I bought some from the store and then turned the heads down to fit on Gill’s superb Monarch lathe.
Next up, is the issue of the rear bearing leaking oil profusely. As the machine is running oil is picked up by a ring and carried onto the spindle. It then runs out both ends of the bearing into a flanged section of the bearing and then back into the reservoir via a small hole. As you can see below, a piece of the flange was broken before I got the machine which lets the oil leak out.
To take this back to factory would require making a new bearing which is something I’d like to avoid right now. Instead, I cut a piece of flashing and formed it to the shape required. It is held in place with a metal band clamp. The back side of the flashing was covered with a thin coating of RTV sealant before putting it on to keep it from leaking at the edges.
With the guards back in place the bandage on the rear bearing doesn’t stand out that much.
The last thing I did was to replace the key in the tail stock. The original one had been worn and allowed the tail stock spindle to rotate slightly under load. This key fit tightly into the tail stock and took some filing to fit correctly.
Once the lathe was back together, I tried drilling steel with a 1/2″ drill bit like I’d done previously. This time the drilling went well and produced some nice chips. Yay!
Now I can get back to making stuff on the lathe.