Model 9A Head Stock Runs Hot

Good Day all,

I rebuilt my 1951 Model 9A several years ago and used it very little. I followed the information published in the South Bend (Ilion) guide entitled 'A GUIDE TO RENOVATING THE SOUTH BEND LATHE 9" MODEL A, B & C & MODEL 10k HORIZONTAL DRIVE, as well as advice from this forum.

Now that I have a need for the lathe and started using it, problems have arisen. Before I start disassembling things and using up my very limited and precious free time, I thought to seek some advice form those who know a lot more than I about these machines. My issues are as follows:

1. The head stock heats up when running, even with the belt tension adjustment set quite loose.

2. Even when the head stock is very hot, I can turn the lathe off, un-tension the belt and the chuck/spindle turns with no drag.

2. The new serpentine belt slips and the chuck slows down significantly even under light loads. I can easily slip the belt and stop the chuck by hand after it runs for awhile.

I changed the spindle bearings and wicks during the rebuild and set the cap bolts according to spec. I've loosened the cap bolts since then with no decrease in the head stock temperature. I am using the specified spindle oil.

I first thought that the spindle was seizing in the bearings, but as stated above, even when the head stock heats up significantly, I'll turn the lathe off and can then turn the chuck by hand with no significant drag.

Any Ideas?

take up collar too tight?

Is this one with the bronze split bearings? It certainly sounds like a bearing issue....it's easy too get false readings for the clearance.

Add a .001" shim to each side and see what happens.

I think you have 2 separate issues.

Hot headstock, What spindle oil are you using? Sounds like the oil is too thick

Slipping belt under low load, either something is slippery (wrong side of the belt perhaps, should be the ribbed side against the pulleys) or the belt is too loose.

CarlBoyd

belt slip likely misalignment....countershaft not parallel to spindle.....or if glue or laced belt misalignment could be the belt itself

If one piece "serp" belt then what Carl said...I have no idea how the inside outbelt thing came to be...one of those Internet things that is wrong and got spread around....its goofy...totally defeats the purpose of using a poly v belt.

When you're check your bearing clearance mount the indicator directly to,the headstock casting...otherwise the bed clamps can flex an give false reading.

only talking .001" so it doesn't take much to throw things off.

iwananew10K said:

take up collar too tight?

Is this one with the bronze split bearings? It certainly sounds like a bearing issue....it's easy too get false readings for the clearance.

Add a .001" shim to each side and see what happens.

Click to expand...

I think a few shims will help decide if it's too tight. If it's too tight, it's not getting oil everywhere in the spindle either.There needs to be just the right amount. if you make it too loose you'll get a quick validation that it's too tight. It will run normally but may chatter on certain cuts. if that works, work it back until you have the right amount of tightness. DONE WITH A ROD down the spindle you should have some amount of play. Can't remember.