South Bend Lathe 14 - Idler Change Gear Bolt and Bushing

[exphiveoh]

I have a South Bend Lathe 14 I finally found the time to start begin to learn to use. Running the machine the middle gear between the gear at the dop that drives the machine and the gear that turns the lead screw. I believe its the idler gear. The square head bolt broke and I'm trying to find a replacement. The SBL part number is PT24T1, however, SBL no longer stocks that part. In looking at the diagram of my lathe and what I think should be happening is that bushing in that gear is what helps hold the gear in place on the banjo to allow the gear to spin. As I said gear and bushing on mine are stuck so I think I need to have the bushing pressed out and figure out a way to make sure it spins or find a replacement. As I need to replace the square head bolt, I'm hoping to find the three parts, if necessary. Can someone tell me if I am correct, the gear spins the bushing stays put?

 

[benmychree]

Yes, the gear turns, the bushing does not turn; as to the bolt, why not make one?, or perhaps someone would make one for you. Yes, press it out, then figure out what is making it bind and remove burrs or whatever until it rotates freely. Make sure to not press againt the rim of the gear, only press against the hub, to avoid breaking it.

 

[exphiveoh]

Thanks benmychree. That makes sense. I that is likely when the bolt broke in the first place the gear and bushing turned and overtightened the nut. If I can get the bushing out and address why it's binding, I'll try to turn the bolt myself good practice project. I modified a similarly sized hex head bolt to work temporarily so I can get a square head machined.

 

[exphiveoh]

I was able to separate the bushing and gear with an arbor press. This machine must have it in someone's shop unused for a very long time. There was corrosion that fused the bushing to the gear in about the first 1/8 inch of the bushing and inside the gear. I put each in a three jaw chuck and cleaned them up with emery paper. Another thing that contributed to the problem is that when the bushing is inserted in the gear it is absolutely flush. That is, the washer with the nut that holds the gear on touches both the gear and the bushing. I clamped the gear on my mill table and used an end mill to take off about 1/32". Just enough for the bushing to clear the gear. It didn't seem like much but it did the trick. The gear is on securely with my temporary bolt and no longer binds. Now I just need to machine a new square head bolt.