MONITOR ‘BALL HOPPER’ HIT N MISS ENGINE

Part 4 - Making bronze bearings 

by Jason Ballamy

With the crankshaft completed I could now make the bits that slip onto it to a known size. Starting with the split bearings, a piece of 28mm bronze was sawn down the middle, the mating faces machined and then soft soldered together.

This was then held in the 4-jaw to get the joint on centre height and then the outside machined to fit the bearing blocks.
As the bearings only had a 1/32" wall I did not trust the solder to keep things together while they were bored so I made up a sleeve from scrap aluminium to slip over the main section but allow me to hold the whole thing in a 5C collet while it was drilled and then finally bored to fit the crankshaft.



 
And a couple of shots of them in place, on the second you can see how recessing the housing has allowed me to move the bearings outwards to help compensate for the undersize crankcase casting.
With everything in place I could now confirm the lengths of the keyways which were cut with a 1/8" two flute cutter.
Part 1  part 2  part 3 Part 4  Part 5  Part 6  Part 7  Part 8  Part 9  Part 10  Part 11
 




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