Clash of the Steam Threshers

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While reading through the June 1871 issue of a journal entitled
The Bureau: Devoted to the Commerce, Manufactures and General
Industries of the United States,
I found an article on page
508 on the ‘new’ Aultman & Taylor vibrating thresher,
which eventually eclipsed the Pitts endless-apron style of
threshing machine. On page 499 was an advertisement for the Aultman
& Taylor, and on page 535 appeared an advertisement for the
Pitts thresher. I thought the ads and the article would be a
meaningful contribution to Steam Traction especially since
the magazine is serializing a fairly complete history of the
Aultman & Taylor Company.

Agricultural Machinery Threshing Machines

Excerpted -from The Bureau, June 1871, Vol 2, No. 9

In accordance with our promise in last issue, we propose to
furnish our readers with some idea of the leading points in
controversy between the two principles of threshing or, rather,
separating grain.

The principle of threshing in all machines is so nearly alike
and effective as to preclude the necessity of any further remark.
The separating power is the great point of excellence to be
maintained. As stated in our issue of May, we select for
illustration the original Pitts and the Aultman & Taylor
threshers, inviting particular attention to the mechanical
construction of both; first in the order of its coming will be.

The Original Pitts

The grain is thoroughly threshed and beaten out of the heads, in
its contact with the cylinder, which forces or drives it down and
forwards. The bulk of the grain, estimated at 7/8 of the whole, is
stopped at the cylinder by reason of the guard-slats placed there
to protect the apron and the openings through the concaves.

This portion of the grain parts contact with the straw at the
cylinder and falls through the open concaves and guard-slats
directly into the troughs or cells of the apron. The remainder of
the grain, mixed through the straw, passes up together on the
apron, which is being agitated by a sharp jerking motion over the
friction pullies on which it rests, until it comes in contact with
the beater, ‘armed with teeth’ and revolving with great
rapidity, which passing through the mass of straw, tears the knots
and lumps to pieces and causes the greater portion of the eighth
remaining therein to fall through into the cells of the apron,
where it is seized hold of by the swift-revolving picker, and the
particles of straw are here pulled apart most effectually, and
spread out thinly on the slat-belt or rake, and whilst passing over
it, is again thoroughly agitated by a vibrating arm or rocker,
which motion fully dislodges the last particle of grain heretofore
adhering to or mixed with the straw.

Thus we see that the process of separation is constantly taking
place from the moment the sheaves are fed into the cylinder until
the clean grain is delivered into the usually attending
half-bushel. First, at the cylinder, when from 3/4 to 7/8 of the
grain falls through the concaves and guard-slats into the apron;
the remaining moiety of grain mixed through the straw, is got out
of it at the beater, the picker, and in the passage over the

Now for the modern reformer, with all the amendments:

Vibrator, or Aultman & Taylor

The separating portion of this machine is made in the form of a
long box, decked over at the top, open at the rear end and divided
horizontally into three portions or sections.

The upper portion or section is stationary. Below this are two
movable sections or troughs, each about 6 inches deep, fitting into
each other. The middle section has a bottom formed of transverse
wooden slats, with spaces between them to permit the grain to fall

Just above this open slat work are placed several sets of
finger-bars with long projecting fingers in each. These fingers
reach from one bar to the other, nearly the entire length of the
separator. To one end of each finger-bar is attached an upright
arm. The upper ends of these arms are connected with the stationary
frame of the machine by means of leather straps, which are
regulated by thumbscrews. The lower section has a tight floor to
hold the grain after it is separated from the straw, and falls
through the slatted floor of the upper one. It also projects under
the concave, which is grated, so as to receive the threshed grain
that goes through the concave and grate. It also projects partly
over the sieves, and is perforated at this end, so that the grain
falls through these perforations or holes, and is evenly
distributed on the sieve. The lower and middle sections are both
suspended on swing rods, so as to swing freely, and are made to
‘vibrate’ or swing backward and forward by means of the
crankshaft and connecting-bars. The two sections move in opposite
directions, one going forward while the other goes backward, and
thus counterbalance each other, so that the machine stands still
without blocking or bracing, and there is no perceptible strain on
the frame.

The operation is as follows: The machine being in motion, the
two sections are vibrated backward and forward and communicate an
eccentric motion to the fingers, which works the straw gradually to
the rear. As soon as the straw leaves the threshing cylinder, it is
deflected at once to the agitating fingers by the circular deck or
deflecting curve. The first rank of fingers toss the straw up with
a few smart rapid blows, and it passes to the next, and so on, over
the successive ranks of agitating fingers, each rank contributing
to the thorough and continual shaking, until the straw passes from
the machine. Meantime, whatever grain goes through the concave and
grating under the threshing cylinder falls into the lower section.
The grain remaining intermingled with the straw is thoroughly
shaken out in its passage over the agitating fingers, and sifts
through the open slat work into the lower section and is conveyed
to the fan mill. The upper section is large and roomy, affording
ample space for the tossing process. The ‘throw’ of the
fingers can be INCREASED OR DIMINISHED (even while the machine is
running) so as to give the straw ANY NECESSARY AMOUNT OF SHAKING,
thus insuring agitation in all kinds and conditions of grain.

Thus, so far I have given in full the claims made by both
parties, and know that the Aultman & Taylor has made a good
solid success, and that it is no longer an experiment. Whilst so
doing I also wish it to be understood that I consider that the
original Pitts, as manufactured by H. Pitts’ Sons, has not
suffered in its well-established reputation by the progress of the
Aultman & Taylor. The Pitts principle has always been right.
Its application by careless and egotistical manufacturers has been
the only wrong it has met with since 1837, the year of its

The coming season will find them in the lists contending for the
championship in the correct principle of separating. I wish all
parties a clear field and no favor.

Historian and author Robert T. Rhode is a regular
contributor to Steam Traction. Contact him at : 4745
Glenway Ave., Cincinnati, OH 45238,

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