From Alemite to Zerk: The History of the Grease Fitting

Sam Moore gives a lesson on grease fittings, which seemed to be in every piece of machinery, especially before the days of modern bearings.

| October 2015

Anyone familiar with machinery of any kind, especially in the days before modern sealed and lubricated-for-life bearings, knows about grease fittings. My first job after high school was grease monkey at a Nash dealership. Back then, each car must have had 15 or 20 of the little things. I don’t think today’s cars have any.

You know what I mean: the little ball-shaped gadget at every place on a machine of any kind where two metal parts rotate, slide or otherwise move in contact with each other. A lot of people call these Zerk fittings or just Zerks, but they should more properly be called Bystrickys or Alemites (I’ll explain later).

Farm machinery made from the 1930s until the present day has always been a heavy user of grease fittings. With wheels and coulters, a plow might have only a few, but a threshing machine or combine seemed to have a hundred (especially when you were all but standing on your head trying to reach each one, wipe it clean and slip the nozzle of a grease gun on the thing straight enough so the grease would go into the bearing, rather than squirting out to the side). And this ritual must be repeated at least twice a day, more often in dusty conditions. Many a pure-minded farm lad has lost his religion trying to get to that one fitting that some diabolical engineer thoughtfully placed just 2 inches out of reach. But enough about me!

Necessity drives invention

In the early days of slow speeds and iron-on-iron bearings (sometimes with a brass or babbitt insert), open oil holes, into which a shot of oil was frequently squirted, sufficed. Of course, lots of dirt got into the holes, so spring-loaded, self-closing metal caps were added, and, in some cases, automatic drip or mechanically operated oilers. Bearings that required what was called “hard oil” (grease to you and me) had a grease cup. The cup held a day or two’s worth of grease and when the top was periodically turned down, grease was forced into the bearing. Henry’s Model T Ford used grease cups and oil holes exclusively.

Keeping all those cups and holes filled took a lot of time and, as usual, a guy who had to do the job thought of a better way. Early in the 20th century, Arthur Gulborg had to keep the oil cups full on all the die casting machines in his father’s Chicago factory, the Alemite Die Casting & Mfg. Co. In about 1916, he devised a screw-type grease gun and a straight, hollow fitting with a spring-loaded ball in the end to keep the grease in.

A flexible hose on the end of the gun had a slotted nozzle that was twisted onto the fitting and was held there by a small projection on each side, similar to the small automotive light bulbs still used today. After greasing, a small brass dust cap was twisted onto each fitting. Gulborg’s gun used a plunger on the end of a threaded rod at the end opposite the nozzle. A T-handle on the outer end of the rod was turned to force the plunger and the grease into the fitting and then into the bearing.