19th Century Flour Mill Shaft Bearing Identification and Disassembly

[madeinta1wan]

Hello Eng-Tips,

First post.

Helping a friend to remove a cast iron drive shaft that has some missing teeth on a coupling and wondered if someone might know how this bearing is assembled (and disassembled)

Within the plate that has a grease fitting on the face theres a lower and upper brass bush that looks to me like it couples the shaft to the next shaft going up out of the photo.

The shaft at the base has some broken teeth in that we've had remade and will weld back onto the shaft when it is free. Currently the shaft presses down onto the shaft below it and is kept parallel with a shaft coupling (pictured). To me it seems that the assembly of this mechanism happened from the ground up and the drive shaft and gear that we are trying to move may have been pushed into the bearing housing and the next shaft above it fitted in with a similar type of toothed alignment/drive fitting.

The question I have is is anyone familiar with this type of bearing/bearing housing? I've taken the front plate off and I can see two brass bushes and a steel/cast iron segment in between.

If I were to lift the shaft and gear slightly allowing the base of the shaft to be disconnected and pulled out of concentric alignment with the shaft below, could the shaft and gear be lowered physically or is there some bolted/mechanical connection with that bearing assembly that centuries of grease is preventing the shafts from coming apart.

Thanks,

Nate

 

[MikeHalloran]

Photo 3 appears to show a rigid shaft coupling.
It is normally disassembled radially, after removing ~8 bolts holding the halves together.
Within it, I'd expect to find two, maybe four, shaft keys, seated in grooves in both shafts and in grooves in the coupling.

I'm not sure what to make of the radial stud/nut protruding from a coupling half near the end; it might be a setscrew intended to keep a key in place.

I would expect to have to massage the coupling halves off the shafts, because they normally fit tightly.

At the time that mill was made, it was fashionable to make bearings and shafts in sizes that were optimized for the torques to be carried, so there's a fair chance that none of the shafts, nor the coupling, are of what we could consider a standard size today.

The pillow blocks with the grease cups should disassemble radially, by removing the double nuts.
The apparent flanges/shoulders at the ends of the pillow blocks do not appear sturdy enough to support the entire assembly.

There must be a thrust bearing at or near the bottom of the stack.
All of the parts are probably quite heavy; be careful.




Mike Halloran
Pembroke Pines, FL, USA