Part 6 by Vince Cutajar

The USS Monitor was an ‘ironclad’ steam ship which famously saw service in the Civil War in the early 1860s. The ship's engine was designed by John Ericsson as a "vibrating side-lever engine." He had created similar engines before and decided to use the design again because of its advantage for a small, low-riding warship.

Most steam engines of the time had vertical pistons, which occupied a lot of space and made them vulnerable to enemy fire because they were partially above the waterline. In contrast, the Monitor's 30-ton, 400 horsepower engine had pistons that moved horizontally, which reduced the height of the engine and allowed it to be mounted below the waterline.

Although a successful fighting ship the Monitor was not stable in rough seas due to its formidable rotating turret and sank in the early hours of January 1, 1863.

The engine was recovered from the Monitor's wreck site in 2001. It is now resting upside-down in an alkaline solution to inhibit corrosion. Over the coming years, conservators will continue to clean and separate the many different pieces of the engine to preserve them properly.

The first model Monitor was shown at Harrogate in 2014 by Brian Stephenson to the design of Bob Middleton. It was built without castings, like Bob’s other designs. Julius de Waal has produced these CAD drawings for both metric and imperial (see here) versions. A double sized version can be found here. Drawings can be downloaded for personal use only.

This one is built to Julius’ metric drawings.

Fitted the crank rods and other parts.

Everything operated smoothly without binding.

A choice had to be made about which material to make the cylinders from. I had these options available:

1)  Metric plans specify an aluminium cylinder with a brass liner and a cast iron piston.

2)  Imperial plans specify a steel cylinder and cast iron piston.

3)  A brass cylinder and cast iron piston.

4)  An aluminium cylinder with a cast iron liner and an aluminium piston.

Decided on making the cylinders from BMS just like the imperial plans show.  I will be using 60mm BMS round stock for these and also the cylinder covers.  Problem is that is going to involve a lot of sawing and I am not looking forward to do it with a hacksaw.  So, finally decided to invest in a bandsaw. 

Meanwhile, I started work on item 45 which are the Piston Rod End Links in aluminium with brass bushes.  Normally, I would press fit the ready made bush but as it is a thin walled bush I was afraid that I might distort it.  So this time I press fitted solid brass material in the holes.

Then I drilled and reamed the brass to make the bush and milled them down to the aluminium surface.
Links were rounded off and bolts made.
Started work on the Cylinders (item 16A).  Cut a piece of 60mm BMS with my new toy.
With stopping to see what's going on and going slowly, it took 16 minutes to do the cut.  If I had to do it manually it would have taken much much longer.  First one nearly ready.  Still need to reduce the length to size.
Finished cylinder blanks.

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