Building the Stuart boiler feed pump part 5

The valve and shuttle piston are strait forward turning jobs. The picture below shows the completed cylinder and valve chest mounted on the base.

The next job was to machine the piston and pump ram. This needs to be done on one setting to keep both ends concentric. The drawing shows the piston packed with graphited yarn. I chose to use an o ring which I hope will make a better seal.

There are a number of small parts needed to complete the steam end including the yoke which is clamped to the piston/ram and controls the vale events.

The dimensions on this part are critical to get a good clamping action on the piston rod.

I had to remake them yoke after testing as I found that it would come loose and the valve timing would be lost.

After the gland nuts were made it was time to test the pump on air, I was not very optimistic as I connected the air supply..........