O.B. Bolton Marine Triple Expansion Steam Engine using castings by AJ Reeves, drawings by John Bertinat

[NMBROOK]

Not so much a progress update, but more an update on purchases needed to finalise the design of some additions to the original drawings.

I have purchased the three gauges for monitoring the valve chest pressures. There are three different ranges on the scales as pressure drops in each valve chest

I have also purchased six small Globe valves for the cylinder drains.Adapter pieces will need turning to connect to the cylinder blocks due to the tapering nature of the block.

 

[NMBROOK]

Bolton part twenty six

I am now on with machining an aluminium block to form a housing for the three gauges which will be screwed to the cladding. I came up with a design that disguised the pipe connections as I feel they spoil the scale fidelity of the gauges if left on show.
I have also drilled and tapped the drains for the cylinders.

As they say, a picture says a thousand words. The three holes behind the gauges are clearance for the projecting screw in the back of each gauge

 

[Roger Pellett]

I have trouble making the love button work. A great example of “cosmetic engineering” I always look forward to your posts.

Roger

 

[Namabiiru]

I have trouble making the love button work.

Story of my life

 

[NMBROOK]

Bolton part twenty seven

Kinda one step backward before moving forward for this small update ( currently working six days a week so progress has slowed)

I produced one of the extension pieces to take the cylinder drain valves but deemed the design too fragile and a light knock could result in breakage.

I decided to bore the six tapped holes out to take 1/4" Stainless extension pieces that would later be held in with locktite bearing retainer. This elevates the step in diameter and means I only have a threaded bore to take the valve, much stronger.

I have purchased some billet brass to machine the oil tank and lid that will be fixed to the cylinder block alongside the gauges. Pipes from this tank will supply lubrication to the crank main bearings simply by gravity. I have chosen to machine this tank from solid as it will give a much crisper appearance than folded soldered brass sheet, plus the tank will be tapered in plan to suit the tapering of the block so the outer face is parallel to the centreline of the engine.

 

[Roger Pellett]

Nice work as usual.

Full scale marine engines injected tallow into the steam to the HP cylinder to lubricate it. I have an indicator from a Great Lakes Steamship that still reeks of tallow.

Is it necessary to lubricate the cylinders of your engine, and if so, how is it done?

Roger

 

[NMBROOK]

Nice work as usual.

Full scale marine engines injected tallow into the steam to the HP cylinder to lubricate it. I have an indicator from a Great Lakes Steamship that still reeks of tallow.

Is it necessary to lubricate the cylinders of your engine, and if so, how is it done?

Roger

Hi Roger

Yes it is. Commonly a displacement lubricator is used inline in the steam feed before the engine containing compounded steam oil.
In this model I have plan to use a mechanical lubricator as the displacement lubricator looks out of place for a scale appearance. The mechanical lubricator takes a drive from an additional eccentric on the crank to operate a lever and ratchet which in turn operates a piston which pumps small amounts of steam oil into the steam inlet via a non return valve
I hope to purchase this item soon and will post pictures when I receive it

 

[Roger Pellett]

Nigel,

A brief post to show a real instrument from the age of steam. This is an indicator. Its purpose is to make a paper trace of pressure as the piston moves through the cylinder. This was used to adjust the “cutoff”; the point where the valve stopped admitting steam to the cylinder. It was used on a Great Lakes aSteamship and is in my collection.

Roger