BS Hardware – II

Gears
GearAssortmentSmallThis is Vector Cut’s HO set of gears and handwheels. I need to sandwich at least two to give a 1-3/8″ thickness. In the pic the larger two gears are exactly the dia of the large gears in my drawing. The two smaller gears are about a scale inch too large in dia. The teeth appear to be a bit long compared to that larger gear but a light swipe with some fine sandpaper will fix that if necessary. I hve one set of the HO gears so I need to order a second.

Note: I went ahead and dropped an order for another set – since the chances of purchasing a laser cutter any time soon is probably about the same as my car getting hit by a meteorite.

Vector Cut Gears
GearsI used the Gear Generator program to create the Vector Cut gears in Sketchup. These were then used in the model.
The Crane
working_3Pretty much the final design using stock styrene shapes.
working_4A close-up look at he gears and pulley. The gears will be from Vector Cut with the pulley needing to be built. As I said .. the other parts will be Evergreen Channel and I-Beam and various rods and tubing.
Sheave
HandChainPulleyThere are a couple of measurements that are critical. The rest aren’t.

  • The hub-diameter is 0.040″. This is to fit the 0.040″ rigid steel wire I will be using for the shafting.
  • The groove for the chain measures 0.025″ wide and deep. This is to fit the Builder’s In Scale 40-link per inch chain.

Everything is is – as best can be modeled. The hub dia I show as 0.082″. That is just an approximate sizing. I note that Evergreen tubing #223 has an O.D. of 0.093″ with an I.D. of 0.039″. This would be perfect. Trying to glue spokes to this hub would be somewhat .. chancy. In fact .. spokes are not completely necessary .. just thought they would look nice. A hub glued into a disk would be much easier. If I were going to build this thing full-size I would turn it on a lathe. The open areas .. possibly cut out with a bandsaw. It might be possible to turn this on a lathe – that would require turning one side, drilling the hole for the shaft, then flipping it 180°, mounting it on a 0.040″ dia shaft (securely) and turning the other side. I may try that just for grins.

Note: I was thinking about turning the opposite side of the sheave. Simply – a 0.040″ shaft with in the chuck with a flat surface for the turned face of the sheave and the end threaded. The sheave slide over the shaft and a small washer and nut to secure the sheave for finishing. The problem might be that the nut won’t hold the sheave from spinning during the machining process. When machining full size objects like this, a method of keeping the work from spinning might be a bolt through the web of the sheave into that flat surface or a lathe dog. That got me to thinking that instead of spokes the sheave could have round holes .. much simpler to do .. drill them. This would make the sheave look ‘cool’ .. and a simple pin on the jig would fit into one of these holes locking it for machining.


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