USS MONITOR

ENGINE BUILD

Part 10 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. Drawings can be downloaded for personal use only.

This one is built to Julius’ metric drawings.


Next, the Piston Rod Gland Nut (item 24).  Two are required and I made them out of brass.  I decided to make them slightly smaller than the plan, with a 13mm AF for the head and the threaded part will be 10 X 1mm.  Half way through the process of milling the hexagonal head, I messed it up.  So that went to the scrap bin. I attempted to do them again and was successful after the lesson I learnt yesterday.  Started with 16mm brass stock and turned and threaded it.  Also drilled and reamed the 5mm hole for the piston rod.

To the mill where with the help of the ER32 Hex Block I formed the head. 
Made a threaded fixture so that I can hold the nut in the lathe and face it off.
I did both the Valve Rod gland nuts but left them on the parent stock.  I will part them off when the Steam Chest is finished.

I also drilled the cylinders mounting holes on the frame.

Could not resist mounting the cylinders with temporary hardware to see how they look but most importantly to check for any alignment problems with the linkages.
No problems found and the crankshaft still turns smoothly by hand.


Made permanent mounting hardware for the cylinders and also the brass oilers for the crankshaft bearings.  The front oiler is a tight squeeze but fits.

After taking a long time to decide what material to use for the steam valve chest and the cover it was decided to use aluminium as per metric plans.  I was lucky to have a piece just enough for them.

Using the bandsaw, I proceeded to cut up the slab of aluminium for the steam valve chests (item 21A) and the valve chest cover (item 22).

And this is what I ended up with.


Part one here  Part two Part three  Part four Part five Part six Part seven Part eight Part nine Part 10 Part 11 Part 12 Part 13 Part 14 Part 15 Part 16 Part 17