Grease gun or grease injector adaptor

This is an adaptor to fit a 3oz Super Lube grease tube to a Dualco grease gun. It may also fit other grease tubes, but see the FYI note below.

A grease gun or grease injector is useful for applying grease to a precise area. With the long tip, it can apply the grease to places where it might otherwise be difficult to apply with your finger. A long time ago, the bicycle component company WTB sold their Goose Grease with an adaptor to fit the refillable Dualco grease gun, which in turn fit the grease fittings on some of their bicycle components. I no longer have the bike parts, but I still have the grease gun, but the threading on the Goose Grease tube is different from the new tube of grease I just bought, so I wanted to make another adaptor.

Dualco now makes a grease gun that will fit squeeze tubes of grease, but I already had this one, and I figured I could still use the refillable metal grease chamber if I need it in the future.

FYI: The threading on the grease injector is 1-1/2"x20TPI. I made it to adapt to 14x1.5mm, though the aforementioned squeeze tube grease gun is designed for a 9/16"x18TPI grease tube. The two threadings are close enough that the few threads should probably fit interchangeably, and the Super Lube really looks more like 1.5mm pitch, not 18TPI (or 1.4mm pitch), so that's what I designed for.

I haven't had this adaptor long enough for it to be a problem, but you will probably want to seal the top of the piece to keep the oil in the grease from migrating out. This may happen because grease is usually an emulsification of an oil and a soap. That means that in some instances, the oil may separate out. Because filament style 3D printers are sightly porous, the oil can wick away, leaving just the dried out soap which may clog things.

The plastic might still be porous enough that the grease tube will pull some air in with even the slightest bit of vacuum- even from the tube trying to snap back into shape after some grease is squeezed out. It should be easy enough to squeeze the tube while pumping the injector to prime it again.

The tall version of the part is intended to take up more volume within the head of the grease gun for less waste when you get to the last of the grease and also to decrease the amount of stagnant grease. However that extra bit increases the area of material that the grease might wick out through. The short version has fewer inside surfaces to seal if you are using brushed on solvent or heat.