SAM Hit ‘n Miss Ep. 3

The cylinder head is one of the more complex parts of the engine. It required a number of set ups in the milling machine, using a dividing head.

SAM16 (800x716)SAM17 (800x602)SAM18 (800x599)SAM19 (800x600)SAM20 (800x761)SAM21 (800x600)SAM22 (800x600)

The crankshaft is next. It is built up from individual parts. To insure a true running crankshaft, we machined the crank webs as pairs. Here, the holes for the crank pin are machined, using a boring head.

SAM23 (800x557)

The crankshaft finished assembled:

SAM24 (800x600)SAM25 (800x598)

The connecting rods being machined:

SAM26 (800x600)

Here a shot of the two rods, almost finished. The only thing missing are the chamfers on the big end, which are needed to clear the crank case.

SAM27 (800x600)

The bronze split bearings being turned.

SAM28 (800x601)SAM29 (800x600)

The finished rod, piston and cylinder.

SAM30 (800x600)

The pistons are made to a very close fit to the cylinder. The piston is about 0.01 mm under size, which allows it to move free, but is still air tight. The groove in the piston is intended as an oil retention groove. No piston rings on this engine.

In the two short videos below, we are demonstrating the fit of the piston in the cylinder. Holding one end of the cylinder closed against the palm of the hand, the trapped air makes the piston spring back until it is released, allowing the piston to fall free.

We are making good progress, and will continue in the next episode.


Thank you for visiting my shop.

If you have any questions, feel free to leave a comment and I’ll get back to you.



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