Thursday 15 March 2012

How to make an ashpan (4) - Getting in a flap!

In ashpan part 3, I'd got as far as making the pan section of the ashpan. Now there is a 'flap' to make which allows the ash to be emptied (hopefully only when intended!). It is an odd-shaped fabrication with a hinged panel and sides to prevent spillage when Sentinel 7109 is in motion. The picture of Sentinel 9622's below shows the general design idea.
9622's Ashpan Flap
I started with the flat sheet cut out from the pan base and welded 2mm mild steel sides shaped to fill the gap when the flap is raised.
Sides in place and ready to weld the cross-piece
I added an angle iron cross-piece to provide some reinforcement and prevent the flap from being raised too high when closed. A good exercise for the Tiggling Stick!
Cross-piece welded in place
Despite Sentinel 7109 being 28 tons, these welds are really quite small. I used TIG welding because it is much gentler where space is tight. Stick welding can be a sledgehammer adding extra metal where it isn't wanted.

I needed to add a pair of ears to prevent the flap dropping out when opened for ash clearing.

Ear clamped ready to weld (sounds painful!)
Pair of ears
At this stage, I concluded that, whilst adequate, the harsh environment that an ashpan lives in would soon cause it to fall apart and that extra reinforcement would be essential for it to have a long life.
Side reinforcement
I welded two rectangular pieces between the sides, the flap plate and the angle iron. Now it feels like a rigid structure capable of the abuse it will receive in service.

Nearly complete: Screwing it all together, add the fixing brackets and a raising and lowering mechanism and apply a coat of smoke-box paint (which I doubt will last very long in service but it makes me happier with the end result!).

To be continued.

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