The tug I've been working on, off & on, for a few weeks needed new bronze shells in one of the shaft bearings. It was an obvious move to say that I could do the job, there's nothing exceptional about it, but I hadn't quite realised how much it would stretch the capacity of my kit. It really was right at the limit at what I could have done unless I got involved in making special steadies etc.
Finished size is 5.5" bore, 11" long, it sits in 'saddles' in its iron housing of 6.5" dia with flanges at either end.
I'd ordered a piece of bronze 1" over length to give me something to get hold of, plus I could only get 5" bore without a wait of a few days, so it was a heavy lump of metal to hang off a chuck and I needed to get some weight off it ASAP especially as it was too big for my steady. Faced & skimmed out both ends & then supported the outer end with a rotating tailstock chuck:-
Then decided the extra inch could be managed without, so parted it off, & then rough bored from either end & then set up the 'blank' in the mill & sliced in two:-
Next soldered the two halves back together & started the finish machining. My 17" DSG lathe is not in its first flush of youth & wouldn't give a very good result on an 11" long bore (I can improve it when I get a chance to dedicate a bit of time to it!), so I decided to do this in the CVA.
Trouble was, I wanted to do inside and outside in one setup but the dia was too great to go over the saddle of the smaller lathe, so I managed to do the OD at one end & then it was back to a careful setup in the DSG to finish the OD, then a couple of minutes with a spring hone to smooth the bore:-
Finally, split the two halves, & put the top half in the mill to slot it out for the oiling rings:-
The final pic shows the bottom half in its final destination, waiting for the shaft. Unfortunately the block casting had been mounted on resin blocks cast in situ, this must have been done with a worn bearing so now it's a few thou too high, we've had to turn the block over and grind a bit off the resin and the next stage will be to shim it back to height.
Re-edited so that four images now show (the limit!) and the fifth can be seen by clicking on the link.