The two flanges on the columns are joined by a ‘link pipe’ which happened to scale out quite nicely to UK 15mm OD plumbing copper pipe. It’s not easy to bend this to a very tight radius as its quite a thin wall so I tend to buy a full crossover plumbing fitting and cut the two ends off. Add two turned steel flanges, a bit of pipe and two internal sleeves to keep the pipe/bend joint inline, and solder.
When machining the flanges on the columns I made a note of the centre co-ordinates and calculated the exact distance between the two, it was then a simple matter to drill a couple of holes on each PCD at the right spacing in some angle iron to make a jig to hold the parts while soldering.
And here it is in place after a clean up.
To keep the valve balls in place requires a cover to the access holes, a couple of bits of cast iron were sawn off and machined to overall size.
The 4 mounting holes were drilled and the centre spotted so it could be clocked in the 4-jaw. Then a spigot was turned to a good fit in the hole and then holding by that a recess was cut into the outer face with a rounded tool to keep the cast look.
I'll make the studs at the end of the job. There is a small length of 1/8" brass fitted to the middle of the spigot that limits the amount that the ball can lift off its seat.
The valve seats screw in from below so a piece of brass was turned down to 18mm and a 1mm pitch thread cut. As it would have been hard to test fit the thread in the completed columns before chucking the brass I turned and tapped a test gauge which is what you can see perched on top.
Next a 1/2" hole was bored to get a good round hole and then the seat cut back at a 30degree angle before parting off.
A screwdriver slot was added to the other end and thats the pair done.
