With the brackets ready to fit, the first one was pushed in place. Using the DRO's PCD function, it was easy to set out the 6 holes for the retaining studs. Tapping holes went through both parts and the bracket was eased out and the holes in the crankcase tapped.
The metal is less than 80 thou thick so my intention was to fit lock nuts in the cavity. That was until the inevitable happened: I had either too much pressure or perhaps not enough pressure on the tap when withdrawing it and the thread stripped. Yes, locknuts are now a definite necessity! That was the first side done. The casting was unclamped and the parallels rotated to give clearance for the bosses on the front of the cylinder. Same procedure as before to line up the casting and repeat drill and tap. Well, darn me if the same thing didn't happen again and another thread came out 'rather loose'. Each housing and the crankcase was centre popped by the top hole: one pop for the front and 2 for the rear, just in case there is any discrepancy.
I now needed some studs to hold the three main bits together. Don't care what the purists might think, but I have some 7BA threaded bar that I'm going to use. Just need a quick way of getting 12 studs to the same 3/8" length easily.
How I did it:
Use any piece suitable of material- in this case a piece of HSS - in the front toolpost as a stop bar + the rear parting tool.
Move carriage towards the headstock so that the parting tool is Just
clear of the chuck jaws. Lock saddle.
Adjust topslide so that the distance between the cutting face of the parting tool and the piece of steel is 3/8".
Put the threaded rod in the chuck and wind the cross slide in so that the stop bar makes a stop for the embryo stud and nip up the chuck.
Wind the cross slide back out and the parting tool will come into play.
Cut off stud, withdraw parting tool, wind in cross slide cleaning up cut end if necessary and pull out the material from the chuck... And so on. Takes longer to write about it than do it. 12 studs in about 5 minutes. I held the stud material directly in the chuck, but there was no damage to the threads.
With everything ready for a trial assembly I discovered that there isn't sufficient room within the crankcase to fit locknuts; the holes are too close to the walls - not my mistake I hasten to add!
A peek inside the crankcase will show what I mean with a potential locknut alongside an inserted stud, so a quick decision determined that two-component locknuts (JB Weld) will have to be used instead.
After having said elsewhere that the castings were undersize, a measurement over the crankcase flats showed that after machining they are 15 thou over! I'm not going to argue with that: I need all the metal there that I can get. I'm sure no-one will notice.
The crank brackets were temporarily bolted in place and I was very pleased with myself when the 10mm drill was pushed through to check alignment, and all did indeed line up.
The brackets now needed the bushes, so these were turned up from a suitable piece of bronze that was long enough for both parts. Taking note of what Brian discovered about wear in the bushings, I made sure I used bronze instead of ordinary brass.
The two bushes were pressed into the housings using the vice. A couple of pieces of padding protected the end of the bushing and the face of the housing. I just started the press and then put a drop of Loctite 638 in the housing as a' just in case' but the press fit was quite tight, so whether the Loctite actually did anything is moot.
The Emerald Isle