I started by milling a hunk of square bar bearing bronze into individual blocks.
Next I milled the recesses between the two outside flanges to create a tight slip fit into the engine block bearing journals.
I milled the bearing blocks taller than needed in order to split the bearing down the middle on my bandsaw.
Back to the mill to finish the split halves.
Split bearings ready for their bores!
Using the engine block as a fixture to ensure good bore alignment for all three bearings, I center drilled and stepped up the drill sizes before the final size of 39/64s.
I then finished the bearing bore with a 5/8 reamer. This pic is of the center bearing being held in the end journal for drilling/reaming. Since it is a wider bearing, it was positioned as high as possible before machining as the drilling process would try to pull it up.
The final reamed split-bore bearing halves.
Machining an oil recess groove in the bottom half of the bearing using an 1/8″ ball end mill.
Bearing caps installed and after test fitting a 5/8 drill rod it appears that the bore alignment is very close to straight but super tight! It will definitely require some break-in time with the crankshaft once it gets fitted.
Hi Mark,
I am enjoying reading your construction blog for the 20 Ton Shay. Thanks for taking the time to photograph and post your progress. Great job!
A couple of questions:
1. Why are the end bearings split? Of course, the center bearing must be split. Was it simply so that you could mill the oil groove in the bottom of the bearing? A plenty good reason if that was it.
2. What is the width of the slot for the connecting rod on the Top View of the Engine Base from sheet E-105. The drawing shows the length of this opening as 3.000, but not the width. I am guessing about 1.1875 to 1.250.
3. In the End View of sheet E-105, what is the width from the center line of the crank shaft to the mounting boss? I would guess about 1.625. The E-105 shows nothing.
4. Had you considered line reaming all three bearings in one set up, in situ? It’s a pain to set that up in the lathe, but I would guess you could do it in your Bridgeport (clone?).
Thanks in advance for your assistance.
Be well & Best regards!
Larry