The Under-mounted Aultman

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Cover of the 1904 The Aultman Co. general catalog, describing 16 and 22 HP Double Star engines.
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An 18 HP 1908 Avery under-mounted engine at the 1984 Central States Threshermen's Reunion in Pontiac, Ill
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Sometimes, owning a particular engine prompts a collector to
delve deeper into the history of a particular manufacturer. With
nearly 50 engines having come and gone over the years, I’ve
learned a lot about many different companies, but sometimes the
information I received was incomplete.

Before I got my under-mounted Star from Bob Lefever, Lancaster,
Pa., I thought all under-mounted Stars were 22 HP, but I soon would
have reason to doubt that. When I acquired my engine, I pulled the
cylinder heads off to inspect the cylinders.

I had two Aultman catalogs at the time: A 1904 Aultman Co.
special catalog introducing the under-mounted engines and a 1906
Aultman Engine & Thresher Co. catalog. For no real reason, I
had ignored the 1904 catalog and used the 1906 catalog for
reference. I had been told (it was even in Jack Norbeck’s
Encyclopedia of American Steam Traction Engines) that my
engine was 22 HP, which I had no reason to question. Using my 1906
catalog as reference for specifications, I set my micrometer to
7-1/8-inch to check the cylinder bores, but the gauge wouldn’t
fit into the cylinders. Assuming I had made a mistake or
miscalculation, I checked the catalog and the gauge again, and it
still didn’t fit the bores measured 7 inches even.

Confused by this, I checked the engine’s other dimensions
against the 1906 catalog and found that nothing matched, not even
the size of the boiler tubes. I began to wonder, ‘What is this
engine?’ Then I remembered the 1904 catalog. I dug it out of my
files, and sure enough, every dimension of my engine matched the
specifications listed. My 22 HP engine was suddenly a 20 HP

A letter issued with The Aultman Engine & Thresher Co. 1906
catalog by the Chicago branch house. The Aultman Engine &
Thresher Co. was formed to liquidate the assets of The Aultman Co.
following its bankruptcy in 1904.

That made my engine older than I thought, as the 20 HP engines
preceded the 22 HP engines in Aultman’s advertising. I knew
that L.E. Mazilly, Starks, La., once owned an under-mounted Aultman
with a lower serial number than mine, so I dug out an old photo of
Mazilly’s engine. On the back, Mazilly had written, ’22 HP,
7-inch-by-10-inch bore and stroke,’ along with serial no. 6766.
I try to avoid assumptions, but I had to conclude that
Mazilly’s information was as limited as mine. If his engine
really had a 7-inch-by-10-inch bore and stroke, and considering its
earlier serial number, then it must also be a 20 HP I have not seen
that engine or measured it, so I will say at this point it is
‘probably’ a 20 HP engine.

Although many dimensions are different, the 20 HP and 22 HP
engines are similar in size and look very much alike. Further, they
are considerably larger and differently proportioned than the 16 HP
Double Star shown in the January/February 2003 issue of Steam
. The 20 and 22 HP engines are so tall that Dan
Gregor, Dayton, Ohio, has shortened the stack on his 22 HP engine
so it is not over height on a lowboy trailer.

Many of us can readily spot the differences in sizes of engines
built by companies with which we’re familiar. With over 40
years of owning, working on and learning about many different
engines, one look at the engine featured in Steam Traction
told me it was smaller than mine. Further, certain engine features
shown in Steam Traction such as the size of the two-speed
idler gear behind the crankshaft definitely confirm it as a 16 HP
engine. The idler gears on the larger engines are actually smaller
than on the 16s.

The under-mounted Double Star that appeared in the
January/February 2003 issue of Steam Traction. Alan New contends
this is a 16 HP engine. (Photo courtesy of John Spalding)

A postcard view of an Aultman under-mount pulling a plow built
by the Lowell Steam Plow Co. of Des Moines, Iowa. (Photo courtesy
of Robert T. Rhode)


For most Aultman engines, determining when they were built, in
what sizes and under what corporate name generally is not
difficult. The double under-mounts, however, present a problem as
they were designed, engineered and built in the final days of a
dying company.

Compounding the problem, it’s unclear whether Aultman’s
engine serial numbers were consecutive.  Russell & Co.,
which resided in the same county in Ohio, consecutively numbered
all its equipment. A number of separators, several hay presses and
a tractor might have been finished between two traction engines
produced the same afternoon, so two consecutive engines could be a
dozen or more numbers apart.

If this were the case with Aultman as well, there is no way to
tell how many engines of any kind were built. Consecutively
numbered engines would have included top-mounted Stars and Moguls,
which were being built at the same time and in greater quantities.
Given that only a few are known to exist, the number must have been


Judging by the three known remaining engines, it seems as if
every one of the surviving under-mounted Aultman engines was more
or less a prototype.

The lowest-numbered surviving engine, the former Mazilly engine,
has three rows of spokes in the rear wheels, a single flywheel on
the right side and long side braces running from the frame to the
sides of the smokebox. My engine, only a few numbers newer, has the
apparently standard two rows of rear wheel spokes and no braces on
the smokebox, but the crankshaft is extended on the left side and
has a second flywheel. Dan Gregor’s somewhat-later engine also
has two sets of drive-wheel spokes, but also differs by sporting a
single flywheel and short braces angling to the lower smokebox. The
16 HP engine featured in Steam Traction also has the short smokebox
braces, yet no catalog or advertising pictures I have seen show
these smokebox braces. The Aultman under-mounted engine was clearly
far from perfected. The smokebox bracing on some but not all of the
engines indicates possible boiler support problems, and my engine
has suffered problems with the stability of the front gooseneck.
Flexing of the frame under heavy load, which throws the engine
cylinders out of alignment, is also a real problem. Dan Gregor runs
his engine with the main bearing caps slightly loose to prevent
crankshaft binding when under load. The crankshaft in my engine has
been broken and welded back together several times apparently due
to flexing of the frame and is currently undergoing major

This advertisement for an under-mounted Avery appeared in the
November 1904 issue of Threshermen’s Review.


By late May 1905, The Aultman Co. no longer existed. Aultman
Engine & Thresher Co. was formed to sell off The Aultman Co.
assets, which included assembling what engines it could out of
parts stocks but not to build new engines. When Aultman failed in
1904, it had a new engine design, a design no other company could
build because Aultman held the patents. But as soon as Aultman
failed, that changed.

The Avery Co., Peoria, Ill., advertised a new under-mounted
traction engine as early as November 1904, less than two months
after Aultman declared bankruptcy. The depicted engine, though
definitely of Avery design, lacked some features of later
under-mounted Averys and showed a slight hint of its Aultman
origins. This may have been a prototype engine that Avery wanted to
get into advertisements as soon as possible, or it may have been an
engraving of a (as yet uncompleted?) new Avery engine.

During liquidation of The Aultman Co., Avery purchased the
patents for the under-mounted engine design from either The Aultman
Co. or Aultman Engine & Thresher Co. This blocked anyone else
from building under-mounted engines at least until Avery’s
patents expired several years later. Importantly, it’s not
clear when Avery bought the Aultman patents. Further, if Avery had
an under-mounted engine in development by November 1904, was it
designed independently or with assistance from Aultman? If it was
built with Aultman’s help, then Avery’s purchase of the
Aultman patents would certainly be explained.

Avery wasn’t alone in pursuing an under-mounted engine.
According to a catalog from 20th Century Manufacturing Co.,
Boynton, Pa., the Improved Traction Engine Co., Elk Lick, Pa.
(which later became the 20th Century Manufacturing Co.), had an
under-mounted engine in the field by early 1905. A.W. Stevens Co.,
Marinette, Wis., also had a new under-mounted design ready to go by
the summer of 1905.

Avery sued Stevens for patent infringement and effectively
stopped them from selling their new engine. According to a story
told by my dad, A.W. Stevens displayed a new under-mounted engine
at the 1905 Indiana State Fair. While the fair was in progress, a
court ruling favoring Avery forced Stevens to move the engine out
of the machinery display area and cover it with a tarp.

Built from the same patents, Aultman and Avery engines were
mechanically similar. The Stevens under-mount was mechanically
different, but the final design was very similar to an Aultman or
Avery engine. In fact, the under-mounted Stevens looked somewhat
like the November 1904 Avery engine.

As to what happened if anything between Avery and 20th Century,
I have no information. With the exception of its boiler, the 20th
Century engine was mechanically similar to the Aultman and Avery
engines. Yet, the finished engine except for the road roller looked
very different. I don’t know if Avery left them alone because
they were a small company in a different area of the country and
20th Century’s engine looked different, or if Avery might have
tried to sue them and lost. Regardless, after 1905 Avery and 20th
Century were the only builders of under-mounted engines in the U.S.
That is, of course, with the exception of the Daniel Best
Manufacturing Co. of San Leandro, Calif., which actually pre-dated
Aultman by several years, but whose engines were very different
than Avery’s.

20th Century Manufacturing Co., Boynton, Pa., introduced an
under-mounted engine in 1905. This 16 HP 1916 engine, perhaps the
last year of production, was photographed at the 1988 Farmers and
Threshermens Jubilee by Charles Harthy.


Sometime in late 1903 or early 1904, The Aultman Co. issued what
it called a ‘Special Catalogue 1904.’ The catalog described
a ‘Radical departure in the design of our heavy engines.’
With several engravings of the boiler, engine and running gear, the
new ‘Double Star’ was announced, and specifications were
listed for two sizes of engines with ratings of 16 HP and 20 HP.
The catalog also said the Mogul boiler could be placed on the 20 HP
frame, thus creating a Double Mogul of 20 HP. Nowhere does it say
this had been done and no engraving of a Double Mogul was shown.
Further, no other engine size was mentioned, and the only other
equipment advertised in the catalog was the standard top-mounted,
single-cylinder Star and Mogul engines, the largest of which were
20 HP.

Later, the company’s regular 1904 catalog appeared,
advertising Aultman’s full line of engines, threshers and other
equipment. Using the same engravings as the earlier catalog, it
listed a 22 HP Double Star along with the 16 HP. The 20 HP was no
longer mentioned, but the Double Mogul was shown and given a
horsepower rating of 22.

Of note was a new catalog cover engraving showing a head-on view
of a Double Star (no engine size given), but with no cab.
Importantly, Aultman tended to use the same engravings over and
over, as did many companies at the time. The cuts of the 20 HP
Double Star in the early 1904 catalog are used again in the later
1904 catalog, as well as in the 1906 and later catalogs, to
describe the 22 HP engine. The head-on view of a 16 or 20 HP Double
Star on the cover of the regular 1904 catalog is the same engraving
used in the 1908 catalog to illustrate a never-before-mentioned 35
HP Double Star.

It’s important to note that engravings are not photos: They
are artist’s impressions commissioned by the company to
advertise its products. I’ve seen engravings of antique cars,
trucks, tractors and many other machines that never existed. Some
were simply artist’s mistakes that somehow made it into a
catalog, some were of proposed but never built machinery and some
were placed in advertisements on purpose for one reason or another.
Many times, the engravings made for earlier advertised products
were simply used over and over again to represent newer versions of
the same or similarly sized engines, tractors, etc.

A.W. Stevens Co., Marinette, Wis., introduced its under-mounted
engine in 1905. Avery sued Stevens, forcing the company to halt
production of this engine.

No engines (or any other Aultman machinery) were supposedly
assembled at the Aultman plant in Canton after late 1905. So why do
later Aultman Engine & Thresher catalogs exist that show new,
larger engine sizes?

I have a 1906 catalog, and I know of a 1907 and 1908 catalog.
Aultman Engine & Thresher Co. sold off the remaining stock of
The Aultman Co. machinery fairly quickly, but the question is to
whom? Most likely, inventory was sold to the old Aultman company
branch houses, which were the primary customers of the
manufacturing company. Lorin Bixler believed the bankruptcy of one
of Aultman’s largest branch houses, the Cedar Rapids Supply Co.
of Cedar Rapids, Iowa, was a major factor that led to the demise of
The Aultman Co.

The branch houses were independent companies supplied by the
manufacturers. Aultman Engine & Thresher probably unloaded the
majority of its machinery to these branch houses, got its money
from them and left them to deal with selling it.

Perhaps to help the branch houses, Aultman Engine & Thresher
printed catalogs well into future years, knowing it would take the
branch houses some time to sell off the machinery, perhaps even
longer than Aultman Engine & Thresher Co. might remain in
business. My 1906 catalog contains a cover letter from the Chicago
branch house. Strangely, the letter makes no mention of the new
double under-mounted engines or any new machinery, despite the fact
a photo of a Double Star is on its letterhead. The catalog
announces the availability of a number of 12 HP and 14 HP engines
‘carried over from last season,’ and advises customers to
consider purchasing used or rebuilt machinery, rather than buying
new equipment!

Catalogs issued into the future to help liquidate equipment are
one thing, but what of the new engine sizes in later catalogs? My
1906 catalog gives specifications for a new Double Mogul engine of
25 HP, but it fails to mention the cylinder bore in its
specifications. The same engine is listed in later catalogs, as
well, yet the cylinder bore is never listed, making it doubtful it
was ever built, and the 1908 catalog mentions a mammoth 35 HP
Double Star.

Most of us are familiar with just how huge 35 HP engines are.
This would be an engine much bigger than my 20 HP engine, and one
that would tower over the 16 HP engine in the January/February 2003
Steam Traction. A Double Star of this size would be similar in
dimensions to the well-known 30 and 40 HP under-mounted Avery.


Could these engines have been built? With Avery’s hold on
the patents, no new under-mounted engines could have been designed
or engineered by anyone connected with Aultman after 1905. If they
had been under construction at the time of bankruptcy, however, and
the uncompleted engines only needed assembling, then they could
have been finished and sold. If that were the case, however, why
was nothing mentioned about them in any advertising until three and
four years after the plant was abandoned, and even after Aultman
Engine & Thresher Co. was dissolved?

Unfortunately, any answers are pure speculation. Maybe the
advertisements were ploys to make customers believe the company was
still going strong so purchases of remaining products would
continue. Maybe the engines had been planned but were never built.
It is anyone’s guess at this point. Never say never, but unless
one of these mammoth engines actually turns up, or a photograph
that can positively identify one, I maintain the 25 HP Double Mogul
and the 35 HP Double Star were, unfortunately, never built.

No dimensions can be taken from the January/February 2003 photo.
However, using the men in the photo for comparison, noting the size
of the two-speed idler gears plus other features and comparing the
proportions of the engine to the one I own and the one Dan Gregor
owns, that could not be a 35 HP

To the best of my knowledge, only three complete under-mounted
Aultman engines remain, and all three are Double Stars. One is a 22
HP one is a 20 HP and the third, if my information is correct, is
also a 20 HP. I have heard that the incomplete remains of a Double
Mogul of unknown size may exist, and I know of a few parts from a
16 HP Double Star that still remain.

I welcome anyone to come and look at my engine and, if you wish,
compare it to that pretty little 16 HP in the January/February 2003
issue. The engine really is a gem, and I’d love to actually see
one. Though it is known that 16 HP engines were built, but thought
unlikely that 35 HP engines were, either size would be just as rare
today. Aside from a few parts for a 16 HP neither sized engine is
known to exist at this time.

A Question of Numbers

Alan New’s research goes a long way toward setting the
record straight on Aultman’s under-mounted engines. However,
one issue not yet settled is the question of who designed the
under-mounted engine, and when.

Writing in the May/June 1972 issue of the Iron-Men
Leroy Blaker noted that Martin J. Hogan, Canton, Ohio,
was awarded patent no. 173846 on Sept. 19, 1903, for his design for
an under-mounted engine. Hogan was The Aultman Co.’s plant
superintendent from 1894 until the end of operations.

Further, Blaker said the 20th Century under-mounted engine was
built under this patent, and that Avery purchased the patent rights
in 1906. However, Aultman’s patents appear to have been sold in
1904, not 1906.

Unfortunately, Blaker’s notes only confuse the issue. An
online search at the U.S. Patent Office
( fails to turn up Blaker’s
referenced patent. In fact, it appears no patents were issued
between Sept. 15, 1903 and Sept. 22, 1903. If anyone knows more,
we’d like to hear from you. – Editor

Contact steam enthusiast Alan New at: 5389 W. 900 S.,
Pendleton, IN 46064.

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