Tuesday, March 16, 2010

High-Bar on a Five-Plank Wagon

I've been working with Oli at the Avon Valley Railway on the high-bar for this wagon.
We'd already made one high-bar on another, similar wagon and so had honed our skills in bending the pipe and getting it to fit the hinge brackets on the ends of the body.
My part in the process lay in measuring up and bending the tubular bar itself and the flat steel brackets that the bar is fixed to and which pivot to allow the whole assembly to fold down and lie along the top of the side body.

Bending the flat bars was an interesting process. We had to put two 30 degree bends into the bars. I didn't know anything about bending allowances so the first try ended up too short. We did the bending by heating the bar to a good yellow-red then clamping it in a vice, being sure to get it horizontal, and bending until it fit a 30 degree protractor.
We were working by eye, so I was very pleased that the bars came out almost perfectly straight. At most a 1mm twist, which doesn't affect the bars' performance or looks.
The round bar-ends were machined by Marcus, the railway's able and energetic apprentice. I think John the engineer did the welding.
They are a fine addition and finishing touch to the restored wagon and will do good service supporting the proper canvas tarpaulin that Oli's got for it.
I suspect I'll be called in to assist with re-making the high-bar on the first wagon. This one made according to the drawings Oli found for the wagon, the first one was a good approximation.

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