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Stack repair

May 13, 2006

As I mentioned earlier I wasted the stack when trying to fit it to the frame. The stack is a key element in the assembly of the locomotive. It holds together the frame and footplate with the boiler and drivers cab. It fits through the smokebox and is attached to the footplate with a thread. This thread in the footplate was too small however and I exerted too much force on the stack, breaking it off at the top end of the thread.


I drilled out the threaded piece of the stack that was stuck in the footplate. That's were I left it until today

Today I have been to a fair and bought some parts to repair the stack.

I disassembled frame and footplate. I took 1,2 mm nut. I glued it to the bottom of the footplate (on the photo lying upside down) making sure that the center of the hole of the nut coincided with the center of the hole through which the lower part of the stack would go.

Next I drilled a 1,2 mm hole in the bottom part of the stack, were the stack had broken off. This was a delicate operation. The stack itself was 2,0 mm thick so there was little room for error.

Holding the stack firm proved to be a problem. It is cone shaped and will not stay in position in a vise. After some experimenting I found a simple solution. I pressed the hard turned steel stack between two scrap pieces of rather soft wood, thus making it unable to move away. After that drilling was easy.

After drilling I took a 1,2 mm bolt, cut the head off and glued it into the stack. In hindsight I could better have soldered it for a more sturdy bond.
A test assembly to see how everything worked out.
There was one small problem left to solve. The nut under the footplate was in the way of the frame. The frame wouldn't sit snug any longer to the footplate. This was a good excuse to do my first ever milling operation. YESS!!
I clamped the frame is a vise on the X-Y-table.
And milled a bit of the frame away, Size: about 4 mm long, 0,5 mm deep.
An now the frame is completely snug to the footplate giving some clearance to the nut.