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Groove Piston & Bore Diameters For 112 Quad Ring

JBartlett

Student
Feb 28, 2025
7
Hello, would anyone be able to help me figure out the correct groove, piston rod and bore diameters to suit a 112 quad ring?

I've checked these recommended diameter charts for dynamic use O rings from Parker and All Rings but they all give me different diameters, see below.

Parker 112 O Ring Recommendations Page 129
https://www.parker.com/content/dam/Parker-com/Literature/O-Ring-Division-Literature/ORD-5700.pdf
Groove Diameter 0.502 inches 12.751mm
Piston Diameter 0.673 inches 17.094mm
Bore Diameter 0.675 inches 17.145mm

All O Rings 112 O Ring Recommendations
https://www.allorings.com/o-ring-groove-design-dynamic-rod-piston
Groove Diameter 0.511 inches 12.979mm
Piston Diameter 0.685 inches 17.399mm
Bore Diameter 0.687 inches 17.450mm

I have a feeling these recommendations only apply to pistons at higher pressures as the differences between the piston and bore diameters are very minimal.
I want to be able to push the piston by hand with a rotating stem without having to apply all my strength to rotate the stem to move the piston which might be solved by increasing the bore diameter but I'm concerned this will lead to a decrease in sealing performance.
 

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