johnsmachines

machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Tag: Bolton 7

May 25, 2015

BOILER PAINT

I am waiting for some new 2mm milling cutters to arrive before I tackle the steam passages in the triple, so I decided to apply some finishing touches to the Bolton 7 boiler.

The aluminium castings on the ends were removed, and painted with a high temperature engine paint.  While the boiler was in pieces I connected the steam exhaust pipe from the engine to the boiler chimney.

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The before shot. The engine and its boiler are sitting on a mantelpiece in our living room.

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It looks better with the ends painted matt black, yes? I suppose that I should have also painted the brass sides and copper boiler, but I really like those metal colours. 

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January 6, 2015

CNC Mill 11

CNC.  That is what started this post.  Today, I fired up the CNC mill, and made a simple fitting for my Bolton 7, which involved some accurate deep drilling in aluminium.  I LOVE CNC!!  Drilling 3mm diameter holes through 16mm material, automatically, centre drilling, then deep drilling  1mm peck at a time and automatically clearing the chips, with positional accuracy of  0.001mm.  Fantastic!  Cannot wait to get more into this.

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Image | April 19, 2014

Boiler for steam engine

Just a bit more finishing on this boiler.
At the chimney end there is now a removable cover to provide access to the smoke box (the round aluminium cover with the brass lever nut), and a sliding door to provide access to the firebox.
You can just see the Bolton 7 engine behind the boiler. They are both sitting on a marble shelf above the fireplace in our living room. I was amazed when SWMBO said that it could live there.
My 18 month old grandson loves to be lifted up to the “teamengine” so he can turn the flywheel.

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Video | April 12, 2014

Making a copper boiler

The boiler which powers the Bolton 7 steam engine is 250x100mm. The case is 1.6mm thick and the ends are 3mm thick. It has 7 x 6mm copper stays. The safety valve, pressure gauge, sight glass and valves were bought items. It operates at 60 psi but has been tested to 120 psi. Propane gas fuel.

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Image | April 9, 2014

Bolton 7 Gunmetal castings

Castings used to make the Bolton 7 engine. These are a hard wearing brass alloy called gunmetal. The next post is a picture of the cast iron castings.
Part of the expertise in making these engines is the technical challenge of accurately machining these lumps of metal.

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Image | April 9, 2014

Bolton 7 Iron castings

A lot of people who see my engines do not know what castings are, so here is a photo

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Image | April 2, 2014

Bolton 7 Boiler changes

The steam exhaust from the Bolton 7 now exhausts into the fire box, and ultimately up the chimney. I am not sure if this will work well. Concerns that the exhausted steam might interfere with the gas flame. Wait and see when I next fire it up! But that will not happen until I make and install a displacement oiler. Another week or two.

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Image | April 2, 2014

BOLTON 7 STATIONARY STEAM ENGINE CHANGES

In the earlier video showing this engine running with steam, there could be heard a knocking noise. Last weekend I did a tear down to identify and rectify the problem. I found 3 separate issues. First the con rod big end was a bit loose, and required some tightening. Then I found that the threaded join between the piston rod and cross head was a bit sloppy, so that was also tightened, then pinned so it will not move again. (see photo). Finally, and of most concern, the 3 bolts holding the cylinder to the bed were loose, allowing the whole cylinder to move slightly. I think that this movement was what was allowing the piston to hit the cylinder cap in use, causing the knocking. I replaced the BA screws with metric 5 cap screws. Much stronger. Much more permanent. And no more knocking.

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