Pump Piston Question

[PeteS]

I am making an aluminum piston for my Silca track pump, since the original piston has broken after 30+ years of use. It is a nice pump and has some sentimental value as it was a gift from my dad so I want to keep it going.

I remember seeing a picture of a machined piston that had an o-ring in a wide slot and holes in one end so it acted as a one way valve, but I have not been able to find the picture again. I started to machine a new piston from aluminum, but would like to see pictures of a working one as a reality check before proceeding further. Can someone point me to a link or post a new picture, drawing, or sketch?

[Gippeto]

Not familiar with the one you describe, but I made this to replace the epoxy contrivance in my stirrup pump(easy stirrup pump). The original piston was still working fine....changed it "because I can".

[PeteS]

Thanks. That helps. I guess it could have slot(s), hole(s), or the edge ground/milled off like you show.

[jrrdw]

Several different styles in the 'Machinist' thread. You can also do a keyword search for 'aluminum piston'.