The firebox door for the Burrell 1/20th scale traction engine is a challenge based on the size of the hinge and latch. The usefulness of the door is questionable as the prime route for firing this engine is methylated spirits. However, it needs to look right.
I searched for traction engine fire door images online and found a number of different designs. The curtain type sliding doors would look superb, but I think that would be too difficult. I came back to a simple door and latch as the easiest to make at this scale. This scale being 1/20th.
The opening in the back of the firebox was machined with a 4mm slot drill and so I have 2mm radius corners.
The hole is 20mm wide by 12.5mm high. The basic door was machined from 1/8″ thick mild steel. The step gives a 2.5mm overlap all the way round.
The rounded edges on the fire door that match the opening were filed.
The door is a loose fit in the opening, hopefully the overlap reduces the heat out.
Hinge
At first I thought I would make the hinges from brass angle. You can see the parts I roughed out in the top of this image.
The brass angle didn’t look right. Hence I thought I would machine the hinge on the door side from a piece of mild steel.
There is still work to do on the firebox door for the Burrell, but hopefully you will agree that this is a good start. The door side of the hinge was rivetted to the main door with two rivets.
The firebox side of the hinge was machined from a piece of 1/4″ square brass. A simple stepped part with a boss to form the hinge body and a thinner area that will allow it to be fixed to the firebox. This thin section was rivetted to the firebox. Once fixed to the firebox the hole for the hinged pin was then drilled. The brass part of the hinge was tapped 8BA. A brass 8BA bolt forms the hinge pin.
The latch is a piece of 1mm thick aluminium that pivots on the door. The firebox side of the latch was again machined from 1/4″ square brass with a 1mm slot. A thinner section was made to allow for rivet fixings. The rivets were countersunk to allow the latch to clear them.
door ajar door latched closed
This door ended up being moved 11.2mm higher to allow it to clear the rear axle. Well, actually to clear the axle cover.