I got my plastic order in yesterday and was able to get started on the girders for the bridge. I'm using 0.030" thickness for all my materials which works out to roughly 1.5" thick. This is about twice as thick as the prototype but 0.010" and 0.020" just looked too wimpy to my eye. All the other dimensions are close to correct according to the book "Bridges and Trestles" by Model Railroader magazine. For flange angles I'm using 6" X 6" (1/8" X 1/8") and for bracing angles I'm using 4" X 4" (3/32" X 3/32").
I'm still waffling on the internal support. I already have a wood buck that fits between the girders but I'm kinda tempted to dismiss that and go with the internal bracing. The wheel dollies are coming from Diamond Scale and will need something more substantial than plastic to attach to. I also haven't figured out how to mount the bridge to the center shaft. I've seen drawings of how the real turntables use a pivot bearing but that won't do here since I'm driving the bridge through the center shaft and not the bridge wheels. I've read a lot about making sure there is a slip fit for the center shaft so there isn't any binding so I just need to put a little more thought into how to build up that area of the bridge.
I don't think I'll be getting the wood order until January so the deck won't get done for a while. Guess I could start thinking about how to build the pit.
One question.....any good ideas out there on how to make rivets in O scale? I saw that Archer makes rivets (1.5") as resin decals but they're $18 a sheet. Same with Micro-Mark. I think I'd spend more on the rivets than the rest of the model. I could try blobs of paint but need to spend some time working with that. Anyone have a good technique for homemade rivets?
Low melt solder containing antimony (M Pt about 158 F) is the stuff to look for (not sure if it contravenes any U.S. EPA etc regs); it's still legal here in Britain. Or "specialist" solder for use on white metal parts.
Michael - both good ideas, thanks. Unfortunately the punch won't work for me since I've already glued up my girders. I like the dress pin idea for bolts. Pretty clever.
I'm going to order a sheet of rivets from Archer. I figured out that I need 40" of double staggered row and 54" of single row in 1" rivets. I worked out their spacing on paper and it looked too wide for O scale so I ordered for S scale. The O scale rivets were spaced at 8.2" and S scale they are about 7". Looked better to me. The book says prototype spacing was 3" and that looks way to close to me.
Last edited on Fri Dec 22nd, 2017 04:39 am by Tom Ward
John - The Grandt Line rivets would work. Thanks for tip on that. Their 0.032" size would be 1.5" in O scale and that's the perfect size for my bridge girders.
"Stick welded"......Ill hafta work on my gluing technique to draw a better bead.
Thanks Si. I'm having fun but progress is slow. I'm waiting until after the holidays to place my order for parts from Diamond Scale. The bridge wheels are needed to get dimensions for the pit rail, correct depth, etc. Working on carving out the pit now. I'll post more next week.