Shire Post Mint Workshop Tour
Here we see two of the working presses on the shop floor. The blue one is a manual screw press with a working capacity of about 40 tonnes. It was made by the American Can Company in Chicago Illinois, probably early in the 1900s. This basic screw press design dates to the 15th century, and drawings of the mechanism are seen in the notebooks of Leonardo DaVinci. This paricular machine weighs about 2500 pounds, (appx 1100 kg) and has just two moving parts. The heavy flywheel is affixed to a steeply threaded triple-lead screw three inches in diameter, which is threaded into a bronze insert in the head-frame and pushes a ram down a set of fixed ways. All the energy of the spinning flywheel is thus focused upon any object placed beneath the ram. The soft metal blank placed between hard steel dies provides a perfect vessel for that energy. All screw presses require an object to strike. Actuating a press without a blank on the dies results in a "clashing" of the dies, which will likely ruin them. All screw presses generate a strong torsion action upon striking, and therefore must be sturdily bolted to the floor to keep from walking during use. The blue press is manual, meaning that the operator must manually raise the flywheel, and accelerate it downward for each strike. It is an arduous and back-breaking labor if carried on for very long!
Typically, the upper die would be affixed to a holder on the ram, while the lower die would be stoutly held in a "die shoe" affixed to the bridge plate on the press bed. The gray machine on the right is a slightly more modern version of the screw press... a style dating to the late 19th century.
This 50 tonne power press was made by the Zeh and Hahnemann
company of Newark New Jersey. It is basically a screw press with a motor
assist mechanism effected by a spinning horizontal shaft overhead... fitted
with two clutch wheels. On pulling the actuation lever the shaft is shifted
longwise such that the right hand clutch wheel accelerates the screw downward
to strike the work. On release of the lever the other clutch wheel engages
and raises the flywheel and screw back up to the ready position. This press
was originally designed to be run from a steam driven line-shaft, but has
been retrofitted with a three horsepower three phase motor mounted on the
floor behind it. The major benefit of this press style is the lesser dependence
on pure muscle to operate it.
The operator is seated in front of the machine and hand-centers
each blank on the lower die.
A further evolution of coin-press design is represented
by our Waterbury Farrel 150 tonne knuckle press, weighing some 10,000 pounds
(appx 4000 kg). This design dates to the mid 19th century and rapidly became
the most popular type of press for large mints. The action of the press
is based on a large sidemounted flywheel with an eccentric behind. The
eccentric actuates the knuckle mounted above the press-bed, moving the
ram a fixed distance with each stroke. Unlike the screw presses, a knuckle
press does not require a target object and may be safely actuated without
a blank present. Knuckle presses, due to the double leverage nature of
the mechanical connection, are more powerful than a screw press of comparable
size. It takes more time and skill to set up a knuckle-press for a coining
run... but there is less risk of damage to dies from clashing. This press
was originally set up to be driven from a steam powered line-shaft, but
was expertly converted to electric power at some point in the past. It
is currently powered by the ten horsepower low-rpm three-phase motor mounted
on top. Knuckle presses have little tendency to jump or walk and therefore
it is not required that they be bolted to the floor.
Below is a panoramic montage showing what the workshop
looks like on a typical day. From left to right: The 13x40 metal
lathe used to prepare die blanks and make tooling for the presses, the
blue 40 ton manual screw press, the gray 50 ton power press, the milling
machine, the 5" x 40" heat treating furnace (looks like a gray barrel)
and a pottery kiln just in front of it, in foreground below is a tool grinder
for lathe bits, the green 150 ton knuckle press stands to the right, with
a small bandsaw below. Further to the right are three smaller manual screw
presses used for punching coin blanks. At far right is a rolling mill for
rolling down metal stock, while in the foreground at far right is a 20x
stereo microscope used while working on dies. Not shown in this photo is
the larger 14" bandsaw, 2 x 72 and 6 x 48 belt grinders, 2 pedestal buffers,
the Gorton 3d pantomill, the precision tool grinder, and the 320 ton hydraulic
press for doing large work.
Will Whitfoot, Postmaster,
Mintmaster
contact: mailto:willwhitfoot@shirepost.com
(Thanks to Daisy
Brambletoes for the above photo of Will in is younger days, and
the more recent one on the previous page with
his lovely wife Rosie!)
Our main activity is te creation of fantasy coins... coins from fantasy realms based on literature, or historical events in the "Real-World", or completely random times and places.
Online Store
...where fantasy coins and other items ar available to purchase
Shire Post News
...where fantasy coins and other items ar available to purchase
Coins
...detailing the early evolution of the Shire Post Mint
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We hope you enjoy perusing this site! Shire Post is devoted to the premise that fantasy is a useful tool in growing our own personalites. We dream of far away places and better times and imagine ourselves in heroic pursuits, and somehow this fantasizing makes us better people in real life, if we internalize the lessons. It further seems that small everyday objects, like coins and stamps and letters from friends, can bolster our "sense of place" and transport us more fully into these realms of thought.
Tom Maringer: MintMaster
contact: maringer@arkansas.net