Part eight by Jason Ballamy

Continuing with fabricating the cylinder, I also shaped the top flange, now you can see why I needed the corners, they will support the A-frames which help retain the beam.

Once all the parts had been machined I silver soldered them together, It went OK but not what I would call perfect as it was hard to get enough heat into the big lumps of bronze. Once cleaned up I spent a long time clocking the cylinder true in the 4-jaw both for concentricity and alignment to the lathe axis, changed the QCTP to the 4-way that came with the lathe so I could mount a 7/8" boring bar and just skimmed the bore with several very light passes followed by similar light cuts to the top flange.

On a safety note, don't try this unless you know what you are doing there is a lot of unbalanced metal hanging a long way out the chuck. If in doubt then don't.

With the top of the cylinder turned true to the bore it was a simple job to bolt that surface to the mill table and machine the bottom and to get the final overall length.

After that the flange around the valve chest was skimmed.

I then clamped the cylinder between two angle plates and finish machined the valve chest and drilled the ports. Anthony mount quite often uses drilled ports rather than milled slots which are a lot easier to deal with and seem to work just as well on engines that are unlikely to do any real work.

The exhaust passageway was then drilled through and the hole threaded and spot faced to 5/8". A similar hole was added on the other side for the steam inlet.

With the cylinder stood the right way up the centre was located and the two steam passages drilled down to the ports and milled through into the cylinder. These are a little closer to the outside edge than I would have ideally liked but not being 100% happy that the solder had flowed between tube and valve block I decided not to drill diagonally as this would pass through the joint line.

The other end was tackled next, first by clocking the bore.

Then with clenched buttocks I proceeded to drill the two 4mm holes through the bronze, as you can see by the amount of drill left in the chuck jaws the holes are quite deep!

While at this setting I milled the passages as per the top, added stud holes and the two gland holes for the valve rods with their associated stud holes.

The 5BA valve chest cover mounting holes were than drilled and tapped.

There are several odd bosses and flanges on the casting these were knocked up and fixed with JB Weld.

And after a bit of a clean up and drilling the pipe flanges I gave the cylinder a coat of etch and this is how it looks at the moment, The last photo will give an idea of the size. I have also bonded on two rings of moisture resistant MDF to help support the planking that will be used to lag the cylinder.

See part one here     See part two here    Part three here    Part four here   Part five here     Part six here      Part seven here     Part eight    Part nine   Part 10     Part 11   Part 12   Part 13    Part 14    Part 15   Part 16