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Identifying an Authentic Whitworth Bolt
By Jack W. Melton, Jr.
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Authentic
Whitworth projectiles will have most of the following features:
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- Lathe
dimple in the nose. This is not always visible or present
but is found on most, if not all, of the Great Britain manufactured
Whitworth projectiles.
- Machining
grooves on the sides of the outer ridges. These grooves
are not always visible due to exposure to elements. Some
of the weathered Bannerman surplus Whitworth projectiles are
salt & pepper pitted so these machining marks might not
be visible.
- Machined
flats that correspond to the Whitworth cannon's rifling system.
On authentic Whitworth projectiles these flats are slightly
concave, with a twist, and are not completely flat. Also,
they should be less that 2.74 inches in diameter.
- The
outside diameter of the ridges should never be more than 2.98
inches.
- Some
Gettysburg monument Whitworth replicas will have a hole drilled
into the nose, that is almost the entire length of the projectile.
This hole is the same diameter all the way to the bottom.
Post-war Gettysburg monument Whitworth's projectiles are slightly
larger in diameter and have holes in the solid cast replica's
so that they can be mounted in a pyramid. The replicas
were held together with a threaded rod screwed into the nose
of two facing replicas. A few monument or replicas maybe
around with no holes but have a vertical casting seam.
These replicas are always larger in diameter than the Civil
War period Whitworth projectiles. Also note: Civil
War period Hotchkiss, Absterdam, and real Whitworth shells were
also used on these Gettysburg monuments.
- Most
Whitworth projectiles were manufactured in Great Britain.
The Confederacy did manufacture a few Whitworth projectiles
but these are very rare.
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| United States Military Academy Museum, West Point, NY |
Great
Britain
Whitworth Pattern I,
Sub-pattern II
DIAMETER:
2.73 inches across flats
GUN: 12-pounder Whitworth rifle, 2.75-inch caliber
LENGTH: 9 7/8 inches
WEIGHT: 12 pounds 11 ounces
CONSTRUCTION: Solid shot
SABOT: None
FUZING: None
This is
the most common Whitworth bolt pattern recovered. Sir Joseph
Whitworth patented this projectile on April 23, 1855, Great
Britain patent #903. His patent information stated:
"...to
projectiles made in a spirally shaped form, so as to fit exactly
the interior of a piece of ordnance or fire-arm made of a corresponding
form."
He
later patented an improvement to his projectiles dated December
30, 1859, Great Britain patent #2990, which stated:
"...in
so forming the projectile that the rear part may have a proper
relation to the fore part with regard to their respective shapes
and weights. The shape of the fore part depends upon the purpose
for which the projectile is to be employed, and may be more
or less pointed or curved, or flat fronted. The rear part is
made to taper, and the weight, form, and degree of convergence
given to it must be determined by and adapted to those of the
fore part. The parts thus mutually adapted present their surfaces
to the action of the air under conditions most favourable to
the accuracy, velocity, and range of the projectile."
The
tapered rear is what determines this as a Pattern I, Sub-pattern
II Whitworth projectile. Click
here to see the 12-pounder Whitworth case-shot.
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| Click
to Enlarge |
Great Britain
Whitworth Pattern I,
Sub-pattern II
DIAMETER:
2.71 inches across flats
DIAMETER OF RIDGES: 2.966 inches
DIAMETER AT BASE: 2.10 inches
GUN: 12-pounder Whitworth rifle, 2.75-inch caliber
LENGTH: 9.39 inches
WEIGHT: 12 pounds
CONSTRUCTION: Solid shot
SABOT: None
FUZING: None
All measurements of this Whitworth were made with
a Starrett, No. 721, Digital Calipers; accuracy +/- .001".
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This
12-pounder Whitworth bolt pictured directly above and below was
purportedly an early battlefield picked-up from the 1863, Battle
of Gettysburg, Pennsylvania. There are numerous scrapes
and scars that would be typical on a projectile fired into the
rocky terrain around Gettysburg. Most of the scars are also
angled with a right hand twist matching the rotary motion of the
projectile when it impacted.
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Scarring from impact
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Machining
marks
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Lathe dimple in nose |
The base is flat |
In the
center of the flat base one can see
where the casting vent was removed.
Click
on images to enlarge
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For
additional artillery information please visit my website at:
http://www.civilwarartillery.com/
The
author welcomes comments and suggestions. jack@jwmelton.com
All Photo Publication Rights Reserved
Jack W. Melton, Jr./www.civilwarartillery.com
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