This log will document modeling the rotary kiln 50′ long tube and tires pictured in the above photo.
1 1/4 inch code 40 PVC has an outside diameter of 1.66 inches, just a hair short of the diameter in the above takeoffs. The connectors that join two lengths are 1.97 inches, also a hair short of the diameter of the tires in the above takeoffs. I picked up a 2′ length of 1 1/4 inch code 40 at Home Depot along with three connectors.
I cut the 1 1/4″ PVC to 12.5″ (50′ in 1:1 scale) with my chop saw and cut the remaining piece in half, fitting the connectors on each end. Then I sliced off a number of sections of the connectors. From the bands on the tube I will select:
- One will hold the tube on the kiln hood end. I’m estimating the with of this piece to be 3′ at 1:1 scale, or 3/4″ in 1:48. That is the size of the longest slice on the tube. It is slanted slightly to counterbalance the fact the tube will be mounted at a slight angle to horizontal.
- Another will be hidden behind the hopper on the far end and serve as a bearing for that end. Width may be somewhat immaterial as it will be hidden inside the hopper. Of the four medium length slices shown I’ll pick one and sand to a slight angle to allow the end to stand vertically even though the tube will be slanted.
- I’ll pick the best two of the three narrow bands and sand appropriately so they can serve as tires.
I plan to make use of a trick I learned from David Fletcher for putting rivets on boilers. If I wrap the tube with thin brass sheet or thin styrene, I can press rivets in the sheet with my drill press from behind the sheet. Final alignment of these parts will be somewhat dependent on the solution used to handle the large gear surrounding the tube. So much of the work on this part of the kiln will need to be suspended until my gear source, the Spirograph, arrives.