Duclos Gearless Ep. 3

The valves are made out of 303 Stainless. The valve stem diameter is 4mm, head diameter 10mm, and over all length is 38mm.

Turning a long, small diameter can be tricky, as the tool pressure will deflect the work piece, causing a taper.

To prevent deflection, while turning the small diameter, I turned it in short sections. It is turned all the way to the final diameter, before starting the next section. The sections are about 8mm (2 times the diameter).


This method turned out a very accurate valve stem over its entire length, without any taper.

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Parting off the valve with allowance for the next machining operation.

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The valve is then turned over and chucked on the valve stem to finish the head.

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Last operation is a 1.5mm hole drilled for a pin and spring retainer. I’m using a sensitive feed drill chuck for this operation.

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Finished valves.

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Valves together with the valve bodies. The valve bodies (or valve chests) will house the valve and are mounted to the cylinder head.

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