Hi, If anyone in interested, I uploaded some jpegs to http://moosedog.home.mindspring.com/.
The pics are three views of a 3d CAD model of the Boxpok driver that I am modeling for one of my G1 live steam projects. The driver shown is a 72 inch, #1 axle, for a 4-8-4 (Northern). The wheel face, spoke holes, rim and hub are all scaled from the prototype. The tire profile and thickness are modeled to G1MRA IF standards (sprung). I still need to decide on how (or if) to add the undercuts inside of the spoke holes that don't go all the way through (as with the prototype). This will make it more difficult to produce the casting but it may be necessary for the wheel to look right. My intention is to produce a set of 74" dia. (2.3125) wheels for myself and for others that may be interested (it's going to be a while before I get that far as I need to do a lot of research on casting, I may have these cast professionally in stainless). I still need to resize the model from 72" to 74" and re-size the spoke holes to accommodate. I used the 72" driver as the basis for the model as I have a prototype that I can photograph and measure nearby. It appears from the references, that I have, that there are several "styles" of Boxpok drivers with spokes that have slightly different visual weights. So I will need to reconcile the look of the model and the photos as a change wheel sizes. Most of the photos that I have show a lighter (larger holes) looking wheel than what I have modeled. I have also included a jpeg of the American project that I am working on as well but is currently on the back burner. The weather has been nice for the past few weeks so I went to the CRRM the get some measurements that I needed to complete the Boxpok driver model. The half cylinder "casting" and the crosshead are "placeholders" and will be redesigned and the frame needs to be lengthened slightly. I am debating on if it would be worth it (or to difficult for the advanced beginner) to spring and equalize the main drivers. This would mean machining axle boxes instead of round bushings and some other parts. I am currently thinking (keep it simple, like with the Dee). I think that the cylinders are going to be "built up" by silver soldering machined sub-parts together which will bring the difficulty up already. Any comments would be appreciated. Ken Vogel
