johnsmachines

No big deal?  This “little” task caused me quite a bit of heartburn.

I had redesigned the flat face of the boiler, including the door and had not really thought through the door design and hinges.

Needless to say, the original hinges as designed by Tubal Cain and Julius deWaal, were quite incompatible with my redesign.

There are NO original drawings of Trevithick’s original designs of this face.  The Rees Cyclopedia drawings do not include this face, and it is hard to tell if the London Science Museum reconstruction is original in this respect.  I did read somewhere that the firedoor in his engines was a casting, so I did not feel bad about silver soldering components to build up the final parts.

In the end, after a failed effort at making a hinge, I decided to wing it, and make something which would work.

This is my interpretation of a Trevithick fire door hinge.  No idea if it approximates Trevithick reality, but I suspect that no-one else knows either.

The tricky bit was silver soldering the 5mm brass tube bits to the appropriate base, and not getting silver solder into the hinge itself.

It was tricky, but it works!!

The latch, the catch, and the movement restrainer come next.  The hinge pin is the cobalt drill which I could not release after the soldering.  Oh well…  cobalt steel should work well.   Incidentally, the stainless steel cap screws will be replaced with studs and square nuts when I around to it.    Now thinking about the propane burner and tubing.