Part 14 by Jason Ballamy
Pistons and plumbing

The governor is mounted on a T-shaped pipe arrangement where the bottom leg of the T allows any condensate to gather and is fitted with a drain cock so any water can be blown down. Not much to say here as its basically just pipes and flanges, the T-joint was formed by plunge cutting with an slot drill the same 12mm dia as the tube to the midpoint and the short piece had its end copied to the internal bore, again with an end mill.

The gears were cut on the end of a bit of 5/8" brass
The governor itself was made from 1.5" brass, starting with a lump for the main body this was drilled, bored and then a 1"x40tpi thread cut in the end.
The top section was then mounted up in the lathe and a matching male thread cut using the body to check the fit.
After which some of the outside was turned to profile
The body was then put back in the chuck and used to hold the top while the remainder was shaped and a hole put down the top.
The two parts were then transferred to the rotary table on the mill and further shape added to the top with a 1/2" slot drill that had its corners ground to a radius which creates the fillets to give the cast look.
The inside of the cut out was cleaned up with a long reach cutter. The next thing was to locate the cross hole for the governor drive shaft which I did my mounting one gear in the collet and checked the mesh against the other. With things running sweetly the R/T was turned 90 deg and the hole drilled as well as a slot to locate the stiffening web.
With the drive shaft tube soldered in I added the holes to take the inlet and outlet flanges.
And here is the main body ready to have the flanges soldered in place.
The parts for the regulator valve prior to soldering.
The profile of the valve handwheel was machined on the lathe before transferring to the rotary table to first cut the spokes.
And then remove the waste.
I decided to use commercial balls for the governor, these are 303 stainless and reasonably easy to drill in their supplied state. A split collet was used to hold them for drilling.
These were Loctited to the arms, I also made the small tee shaped legs that stop the balls dropping too far.
As this engine is only likely to run on air I added a finishing touch with some ‘Slaters’ letters, these are 2mm high.
And here are a few shots of all the bits fitted together. Notice the bracket to support the other end of the governor drive shaft.


Part 14 by Jason Ballamy

Building the governor