I didn't feel like milling the side pieces to get the 1/8" lip, especially as I only had an oversize lump
available. So I filed the edges of two pieces and mig welded them together and then milled off the surplus
which appears to be OK. To match up the stud holes, I used superglue to hold them in place and drilled the
centre block first, then the other side. The glue holds long enough to get the position and a few turns
of the drill before it gives way. The final stage after bolting together is to finish off all faces on
the linisher. The drawing gives the die block as bronze, but as the assembly is mild steel, I'm going
to use cast iron.
The centre part of the assembly is held on the weighshaft with a 3/16" pin which is hidden under the side
pieces. The drawing omitted to say at what angle the assemblies are fitted in relation to one another. I
checked with another loco using the same gear, and of course they are in the same plane to each other.
When I assembled everything I immediately realized that something was out of square. I had done another
milling job and as sometimes happens,
at the end of a stroke the mill decided to climb all over the job
which wrenched the head of the mill just slightly out of vertical. Not enough to notice, but it showed up
on the next job. So, only one thing to do; rebore and sleeve. Here was the problem of how to hold the two
parts for reboring when the sides are sloping. I solved it by super-glueing them together in opposite
directions, as in the photo. I haven't as yet discovered why there is a slit necessary, but it gives
problems when sleeving as when the sleeve is cut, it springs to a smaller size. However, I eventually
managed to fit it all together to my satisfaction.
Having completed the fitting together of the blocks
and assemblies, I didn't like the design of the open ended housing. I'd heard tales of the die blocks
coming out under extreme driving conditions. I looked up the drawings for a 'Sweet Pea' in EIM and found
that the design it used stopped this from happening. So I rebuilt the housing. Bit of a waste of time
probably, but at least I know no die block is going to come out accidentally. I did consider one other
modification which I might do one day; to eliminate wear in the housing I have seen a design which uses
a ball race, and hence no wear. I'll see what it's like at the end of a running season first.
I found I spent a fair amount of time getting the lengths of connecting rods just right, particularly the
reach rod and the pivot point on the reverser. Hopefully, I've got it right but I won't know until I test
it on air; that is, if my compressor can supply enough.
I'm not too keen on the appearance of the rod connecting to the valve rod because it has to be a swan neck
and it would have looked much better if it had been straight. I now have to decide on what if any, part
to be painted and what colour. Many Romulus have rods painted red, but I'm still thinking about that.
I've left it rather late to order a boiler, but I was waiting to see what would happen about the new regulations on boiler construction. Nothing seems to have changed and shopping around, I couldn't find any boiler maker constructing Cat 2 boilers, which is what a Romulus is. So I've ordered a steel boiler. It is being made in a batch with 5 others; popular loco! One thing, it's much cheaper than copper. The boiler maker is quite happy with the changes I want made to the boiler which differs from the original. It is a little longer in the smokebox (the boiler and smokebox are made it one when it is made of steel). I want other changes, like the blowdown moved and the steam dome set back etc. In copper, I could have had a kit and made my own, but I wasn't too happy about that as Oxy-acetylene is a must and its weight meant lifting gear and a big tank of acid plus washing tank.
When I finished the other side, I
found that there was nowhere near enough travel on the valve rod. I knew that all the pieces were the
same as they were made in pairs. So, the only thing that could be wrong was the angle of the eccentric rod.
I removed the pin having set the piston in full forward position, and gently tapped the end of the
eccentric. I was surprised to find that a matter of 1 degree was enough to cure the problem. This meant
reaming the pin hole larger, so to avoid it slipping, I used loctite first, then a tapered reamer and made
a suitable cotter pin. Hopefully that's cured the problem. Anyway, I rotated the wheels through 360 degrees
several times and each time both sides of both valves were just as they should be. If I've finished all I
can and I'm still waiting for the boiler, I will make new crank arms and this time without the split end.
That's as far as I've got this month.