Making a lantern for the lamppost engine.
The lamppost engine has sat on display for years and gets run on compressed air every now and again.
It was always designed to have a lantern on the top to finish off the design, I had also played with the idea of running a generator from the flywheel to power a small LED.
Basic Dimensions
I worked out the basic dimensions from an image of a street lantern that I found online.
Best to print the image in black and white, wash out the image and then draw onto it using brighter colours.
This immediately showed me the angle of the lantern was 14°. This also clearly shows that lines drawn on the edges meet at a point. This point and hence radius allows the complete 3D lantern to be drawn easily.
Marking Out the Brass Sheet
Marking out using arcs and radial lines. Adding straight lines and marking internal windows. Roughing out the brass. Using holes as access for the fretsaw blade. Carefully fretsawing the brass out of each section.
Filing the Lantern Panels to Size
The brass panels had been cut out roughly, but I needed to accurately file them. For this I made up a simple clamp using 1/4″ mild steel beams, fixed at each end using 6mm bolts. The edges of the mild steel were hardened using a case hardening compound.
A brass square was cut for the bottom with a 6mm hole through the middle. This hole was used for a simple screw to fix the base to a piece of wood, thus holding the base square.
A thin copper wire holds the folded lantern closed whilst I soft solder.
Offering up the lantern to the engine.
The original top green pip had an oil hole through the middle. This unscrews and in it’s place I needed to fit the upper part of the lamp post.
Soldered Lantern Frame
The upper section has a post at 90° with a bearing machined at the end. This will be used for the swing arm to which the generator will be fixed.
I have the basics of the Lantern for Lamppost Engine. I now need to finish the top finial, add a bulb, glaze the lantern and oh, add a generator.
Plans for this engine are now available as a downloadable pdf. Check out our lamp post engine plans.
In these plans we fully describe how to mark out and assemble the lantern as part of the overall lamppost project.
on page 8 of the plans Valve & Eccentric Strap what is the distance from the bottom of the Valve Rod to the centre of the 8BA brass bolt pivot, any help would be greatly appreciated.
Hello Duncan, apologies for this error. I just measured this off my engine and it is 70mm as measured from the bottom of the sliding valve.
Best regards, Nigel
what voltage of motor and bulb do i need
Hi Duncan,
I used a small 3V motor: Dynamo for Lamp Post Engine
Just looking on ebay this is similar to what I used: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=ebay+3V+solar+motor&_sacat=0
The lamp was a small yellow LED, I found this lit up the easiest. Test rotational direction of motor and attachment of LED before soldering.
Hope that helps, this part of the model I found to be a bit hit and miss. Best regards, Nigel
Hi Nigel,
Your ver novel Lamp Post engine as created a lot of interest on the MEW website. Lots of comments about its interesting design and many forum members looking to reproduce it, myself included. If you managed to detail draw the parts as you went along, I would be interested in having sight of them and making a start on producing it. No worries if you have sorted out an article for MEW, as I’ll wait for that. Cheers, Jim
Hello Jim, I have some parts dimensioned, not all yet, but trying to make a start on a simple set of plans. Will see what I can get together and will send you an example page to see if they’re on track. Thanks, Nigel
Hi Nigel.
Thanks for getting back in touch. Look forward to seeing some drawings. Maybe I could proof read them ? Best of luck producing them from the ideas in your head ! Jim.
Hi Jim, a proof read would be great as they will be old fashioned hand drawn plans. My CAD skills are very very basic at the moment. Also, I’m drawing and making a 1/20th scale Burrell traction engine at the same time and so this will be a good test. Cheers, Nigel