Trevithick Dredger Engine Progress

by John

First day of summer in southern Australia today.  And it was very warm and windy.  Keeping my eyes open for snakes, but none seen.

I was pondering how to attach the crankwebs to the flywheel.  I had decided that I would not silver solder them together, because the heat would likely distort the thin flywheel.  And pressing them was not feasible because I had machined them to a sliding fit.  Whatever method was used, I wanted it to be reversible i.e. future disassembly possible.  So, in the end, I used small brass screws which will not be visible when the engine is painted.

 

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countersunk brass screws holding the assembly together.

 

I made 2 more U shaped bearing retainers to fit on the ends of the connecting rods (same as shown in last post).

Then made 2 shafts which will be attached to the cross head bar, to join to the con rods.  These are made from silver steel.

 

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The concave end had a radius of 10mm.  Fortunately, I had a 20mm end mill which worked well to produce the curve.  A bit of finishing required for these parts.  I will probably run them for a while in my gemstone tumbler to knock off the sharp edges and polish them.

 

 

 

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They will be pinned in place at the ends of the cross head bar.