20-Ton Bottle Jack Pressure Release Knob

thingiverse

This knob is designed to fit my 25-year-old 20-ton bottle jack for my press. The dimensions are different from the Harbor Freight bottle jack knobs, so I had to design my own knob. The shaft diameter is 0.35 inches The pin diameter is 0.15 inches The pin length is 0.92 inches The clearance between the pin and the base of the jack is only 0.09 inches. The amount of shaft that protrudes beyond the pin is 0.15 inches. I wanted the knob to be a snug fit and the finger notches of the knob to be rounded. The entrance for the pin seat is smaller than the pin diameter, so the knob has to be hit with the palm of the hand to seat the knob on the release valve. A picture is included showing the knob fully seated. I chose to design only 4 points on the knob for simplicity. The fit of the knob in the hand is very good. I hope this knob design can be used by others.