The Coffee Mill: A Cracker, a Grinder and One Screw to Set Them

"This invention relates to an improvement in that class of grinding-mills commonly known as 'box or hand mills,' and in which the runners are mounted on a vertical spindle provided with a crank for turning in a horizontal plane, and specially to that class in which two runners are employed with the different shells, the upper as a cracker and the lower as a grinder." "In this class of mills the runners have usually been formed upon independent spindles, the two spindles coupled together and supported upon a bridge below". "The object of this invention is to unite the two runners upon a single spindle, whereby the bridge may be dispensed with, and the adjustment made at the upper end of the spindle". "By turning this screw in one direction or the other the crank is raised or lowered relatively to the upper end of the sleeve L, and accordingly raises or lowers both the runners. The usual hopper T is provided, through which the material to be ground passes, first to the cracker, and then to the runner, in the usual manner."

Weigh 20 g of whole beans three times. Grind the first at the mill's coarsest setting, timing the turns; move the adjuster half a turn finer and grind the second; half a turn finer again for the third. Put each grind through the graded sieves, coarsest on top, shaking for one minute. Weigh what stays on each sieve and plot the three size spreads. Brew each the same way and note which tastes thin and which bitter: that is the notebook's surface area at work.

**Dexter W. Parker** of Meriden, Connecticut, assignor to **Charles Parker**, filed US 187,898 on 22 November 1876; it is dated 27 February 1877. **Honest limits.** The patent gives no pitch, angle or particle sizes. The screw pitch, runner angle, density and sizes in the notebook are examples; your sieve weights are the measurement.