Transitional Engine Eccentric Bracket

Bellcrank bracket

The transitional engine eccentric bracket supports the pivot for a bellcrank midway along the pushrod.

Bellcrank bracket

This is the part in question, machined from mild steel with phosphor bronze inserts.

As you can see, there were a number of machining operations on the milling machine to get to this final part.

This started with a rectangular block of mild steel that I machined a step into and then machined the rounded outside ends. The slot in which the bellcrank sits was machined next, but only after cross-drilling and fitting a phosphor bronze bearing.

I’ve not shown the stages and machining operations, but this has taken me a long time to machine.

All of the options required me to first disassemble the engine.

transitional engine
Some slight rust on the hidden face of the crankcase
silver soldering Bellcrank bracket

After machining a slot in the crankcase I then silver soldered the bracket to it. There really was no going back now as I’ve spent a lot of weekends making these two parts. As much as anything I was nervous about warping the crankcase with the heat and possible surface damage.

I silver soldered using a blow torch and my trusty homemade hearth.

Luckily the silver soldering worked fine and I now have a solid bracket and pivot point for the bellcrank.

Bellcrank bracket

Transitional engine eccentric bracket in place and the engine reassembled.

I’m very pleased with the overall looking. Although, I probably could have finished the bracket closer to the pivot point and then had the bellcrank sticking out.

About Nigel 247 Articles
Have been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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