Pulley Support

Fig_96The Pulley Supports .. or Station Pillars “support the intermediate pulleys of a compound transmission”. That last bit is taken directly from A treatise on belts and pulleys. It continues – “To support the pedestals for the axle of a pulley of this kind we may with propriety build up a frame-work of wood; it is, however preferable to use a solid pier of brick or stone, upon which are fixed either low or …high pedestals. … The pedestal-plates are fastened to the pier by means of four strong anchor-bolts passing through the pier into the foundation.”

The example from the book as shown here was made from brick and stone

With that in mind I cobbled together my own version from concrete.

Sketchup design
SW_turbine_OscaleI need the output shaft from the turbine drive a pulley .. that drives a belt .. that transfers power to another pulley, from which the output shaft runs into the powerhouse. Following the basic shape in the drawing above I made mine in concrete as I said. The book is from 1885 .. so by the time my structure was built, concrete had come into vogue.

This is a simple representation of what I wanted (the distance between the pulley supports as shown can be ignored as that is just for making a pretty picture).

master and pennyI cobbled together a master from styrene. In the pic to the left I have used some automotive spot putty on top of primer – waiting for the sucker to dry before sanding. The penny of course, is simply to show the size.
Mold Box
mold with masterI glued the master on a small 6″ sq. bathroom tile and then surrounded it with enough legos for a mold. Masking tape is quick and dirty to keep the RTV from getting away. The inner surface of the legos and the master were then coated with mold release.
Making the Mold
rtv moldI used OOMOO 25. This is an equal amount of parts A and B. To figure the amount needed I poured rice into the cavity – a great way to find this out. The RTV sets up in 75 minutes. You then final cure it by putting the mold into the oven at 150° for 4 hours.
Finished Mold
master and moldHere, the master and the mold that was made from it.
castingsA couple of casts from the mold. I used a Dental Stone for this. They came out pretty well with only one with a small bubble which will be easy to fix. The next step for these is to work on coloring the ‘cement’ .. to look like .. old, weathered cement!

I still have to create the ‘pedestals’ as mentioned in the book. For me they will be more like what I think of as bearing-blocks’ .. the only thing I have to be careful of here is that the center of these pedestals/bearing-blocks alings with the output shaft of the turbine.

stackedWorking on the Pedestals/Bearing-Blocks. This is the third try. The second iteration didn’t work as I used too large bits for the upper section .. which is fine except that one of the pieces flew off into who-knows-where and I still haven’t found it.
finished_1Pulley support, pedestals and pulley
finished_2With both pulley supports. When installed on the layout the rear support will probably be further back. I still need to come up with a belt.

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