Dual Proportioning Valve

    This is a proportioning valve with dual variable orifices.

    While this part did not require us to build or modify a machine it was still a challenge to make.  The OD of the cylinder was made by using a 2 axis tracer mounted on a Logan lathe.  The OD profile had a total tolerance of .0009.  The 2 axis tracer was, at the time, the latest in machining technology.   The ID took a little bit more creativity.  We traced the ID, but we used a manual tracer.  We forged our own boring bars out of high carbon tool steel, and ground the tools to shape.  Using a Logan lathe we manually moved the boring bar along a cam to generate the ID profile.

    The spool was fairly straight forward.  We turned the OD profile using a 2-axis tracer on a Logan lathe, and also turning the small grooves.   The variable metering detail was done on a 3D pantograph.  Again we made our own milling cutters to generate the correct geometry for the spool.

    Both parts were then hard anodized.  We then ground and lapped both parts and fitted them in a temperature controlled environment to a diametrical clearance to .00003".