JOSHUA HENDY Stamp Mills
Photos of Joshua Hendy Stamp Mills manufactured in San Francisco as seen during the summer of 2009 in the Sierra Nevada Range. Specific location of these is omitted to preserve their integrity. (Someone has been dismantling historic items such as this and selling individual parts on the internet.) Please leave them in the field for others to find and enjoy.
Here are five illustrations of stamps mills produced in San Francisco by the Joshua Hendy Iron Works Company during the early 1900's.
Can you identify the parts of a typical stamp mill? A key is produced below these five stamp mill illustrations.
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Four Post Battery Frame Seldom used due to its increased overall height and cost over a three post stamp mill; the advantage of this stamp mill was it seldom had a broken camshaft
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| 10-stamp mill mounted on concrete mortar blocks; the ore bin was located
to the rear
Stamps could be ordered from 850 pounds to 2,000 pounds each; stamps heavier than 850 pounds were not recommended for pack animal transportation
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Cross-section of a standard battery frame with wood mortar blocks Can you name the components of this stamp mill? (a key is provided below)
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| The order of drop
in a stamp mill
The most desirable order of drop was usually a 1-4 or a 1-5 drop. the 1-4 drop was 1-4-2-5-3 meaning that stamp 1 dropped first, 4 was second, 2 was third, 5 was fourth, and 3 was last. This drop was also written as 1-3-5-2-4 which is the same, but written backwards. this drop caused the ore to build up on an end of the mortar resulting in an uneven distribution of labor on the dies. The 1-5 drop was completed in the order 1-5-2-4-3 or written backwards, 1-4-2-3-5. The drop became the favorite as it gave the most satisfactory results ever found. The illustration here shows 10 stamps which commonly used the order 1-6-5-10-2-7-4-9-3-8. |
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| Here is
a side-view of a four-post frame battery of a 10 stamp mill
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Main components of Stamp Mills as shown in the illustrations above:
A - mortar
B - chuck blocks
C - screen frame
D - filling in board
E - screen keys
F - rubber cushion
G - screen
H - shoes
I - stamp heads
J - stamp heads
K - tappets
L - cams
M - stems
N - camshaft
O - sleeve flanges
P - battery pulley
Q - camshaft boxes
R - camshaft collar
S - guides
T - jackshaft
U - jackshaft boxes
V - jackshaft collars
W - latch fingers
The illustrations here were from: Joshua Hendy Iron Works / STAMP MILLS, San Francisco, 1911.
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