Bullet and Shell Civil War Projectiles Forum
Relic Discussion => Artillery => Topic started by: scottfromgeorgia on February 25, 2011, 01:05:40 PM
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What's the consensus on this - are these lathe dimples really indicative of Confederate manufacture?
http://cgi.ebay.com/Whitworth-Bolt-2-75-Confederate-Usage-Civil-War-/370486117205?pt=LH_DefaultDomain_0&hash=item5642b18355 (http://cgi.ebay.com/Whitworth-Bolt-2-75-Confederate-Usage-Civil-War-/370486117205?pt=LH_DefaultDomain_0&hash=item5642b18355)
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Hello Scott,
Unfortunately I cannot answer your question with any assurance of being correct. I have emailed Jack Wells who is very informed on the Whitworth. Jack Melton also is very knowledgeable on the Whitworth.
When I think of a lathe dimple and think of the 'dead center' of a lathe, that being said the nose end would also need some sort of support for the 'live center' (chuck end).
I am wondering could it be a stilt support during casting. Perhaps our experts can shed more light.
Regards,
John aka Bart
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Here is one I own that came out of a GAR Hall (apparently). The dead center of the nose has no dimple at all, but there is some kind of chock mark (?) off center.
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Scott,
I spoke with Jack Wells and he intends to reply when he gets the time. Busy man.
Live centers (Chuck end) do have cone shaped faws that could fit the shell or bolt nose in order to turn off the ridges between the flats to the correct diameter. But let Jack speak to this.
In my opinion, either side could have turned them.
Regards,
John
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None of my British Whitworths Shells ( 3,6,12, Pdr.) ,have lathe dimples in the base,however my 12Pdr.Bolt has a lathe dimple in the nose.I am unable to tell on my short 12 Bolt or 80 Pdr bolt due to condition.In an 1865/66 edition of the "Engineerting Journal" there are articles showing a Whitworth mold for injecting molten metal into in under pressure to make a more uniform,and with less impurities projectile,and a "Duplexing lathe is also shown for turning off any excess and to insure proper bore fit.This would required a centering pin in one end,so the projectile would turn "True",there by a lathe dimple would be on the projectile.Were these machines here during the Civil War,yes the Fayetteville Arsenal had a British Machine for producing Whitworth Projectiles ,and I would suspect there were others at various C.S. Arsenals. Also the Union,could have produced Whitworth Projectiles,as the first Whitworths were a six(6) gun Battery which was presented to the U.S. from U.S citizens living in England,along with the guns, was machinery for producing "Shot.Shell,& Shrapnel.".Having found my first Whitworth Projectile some 61 years ago and over the years having owned at least two(2) doz.Projectiles ,I do not think a lathe dimple,is any indication of the projectiles provedience. Charles.J.Wells (Jack)
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Wow, Jack. You've owned a significant number of all the ones around.
I did own a 12 lber bolt quite a few years ago (~16). It was purported to be from the Ft. McGilvery area of the battle of Petersburg, Va. and to be CS manufactured. I remember it had very distinct dimples in the nose and base as well as lathe marks on the outer circumference. It was a really nice nice dug one that I should have tried to keep.
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Thanks, Jack and John.
I note that Jack Melton writes on an online article (http://thomaspublications.com/civilwarprojectiles/articles/12pounder_Whitworth_Bolt.htm) that:
Authentic Whitworth projectiles will have most of the following features:
1. 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.
2. 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.
So some think the lathe dimple is a sign of the Confederacy, Jack thinks it is a sign of British manufacture, and you think that it does not indicate anything at all.
Interesting!
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If Colonel John Biemick is inclined to chime in on this subject, he has done a very thorough study on this. He has written an extensive paper on which is beyond theory and will probably be regarded as reference, once he releases it. Possibly he might be saving it for his encyclopediac book he is nearing completion on covering every known muzzle loading projectile known to exist.
I would like to share more, but I dare not take away his thunder for the hard work and research he has done, it belongs to him and is his property to release when he is so inclined. Suffice it to say, it is a multi page paper and detailed to the 'T'
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Thank you Dave for your very kind remarks and I will share some of the information that I sent you regarding your Confederate Whitworth. I have indeed done a very comprehensive examination of 2.75-inch Whitworth bolts that were manufactured by the British, replicated by the Confederates, sold by Bannerman’s and specimens that have been recovered from battlefields. My friends and I have actually made some battlefield recoveries so I know where they were found and I can certify their origin.
Sidney Kerksis and Tom Dickey were perhaps the first to document that the Confederate’s manufactured 2.75-inch Whitworth projectiles for the rifles they imported. John Bartleson further documented this in his epic book and Peter George and Thomas Dickey further acknowledged this in their great works. From my research and observation, the Confederates used two manufacturing methods.
The first method used bar stock to form the projectile. (Reference: Sidney Kerksis and Tom Dickey, Field Artillery Projectiles of Civil War, page 228). They cut bar stock to form a blank and turned the nose and the tail to achieve the correct shape. These projectiles have crude lathe marks on the nose and tail and lathe dimples on the nose and base. The flats were not lathed, but were brought to tolerance by a surface grinder. Don’t ask me how they did this, but you can’t lathe flats. In any event, this was not a cost effective method, must have consumed a lot of machine time and these projectiles are very rare. My research reveals that at least one gun was blown up by “homemade ammunition” at Washington, NC in 1863. ). Dickey and George show this projectile in later editions (Dickey and George Field Artillery Projectiles of the Civil War, page 292 and the revised edition [1993]), but drop the reference to being cut from bar stock.
The second method was far more sophisticated and used a precise casting as a blank. The flats were machined to final tolerances and there was no need to lathe anything. I have been told the Fayetteville Arsenal had this equipment and manufactured these, as confirmed by Jack Wells. Other experts have told me they were also produced at Tredegar and John Bartleson has confirmed that from his research. For a reason unknown to me, most of these projectiles have a lathe dimple on the nose and not on the base, but none have a lathe lug as they weren’t lathed. The dimple was likely to align the surface grinder to finish the flats, but was not to align a lathe. The base on these projectiles is flat and does not have a precise finish, as do British projectiles. The collector’s consensus is that most of the projectiles that are in excellent condition were sold by Bannerman’s after the war. They purchased most of the Union and Confederate surplus ordnance that was sold by the federal government after the war so this makes sense. Confederate bolts have slightly greater windage on the flats for safety purposes (they were not as precise as the British specification), but we can ignore this for now.
So having noted this, the question is where is the proof to back-up these statements? The most compelling evidence is in the weight of the cast iron, per square inch. British iron is so pure it weighs significantly more than Confederate cast iron, except for that produced at Selma using their air furnaces. Wrought iron weighs more than cast iron, but 2.75-inch Whitworth projectiles are not made of wrought iron, so we can skip that technical subject for now.
The bottom line is that typical Confederate cast iron weighs about 0.253351 pounds per square inch. British cast iron since 1759 has weighed about 0.2685743 pounds per square inch. It is very pure, very hard and is very heavy compared to any other service. Thus one pound of British cast iron weighs about 6% more than the average weight of Confederate cast iron (except Selma). While this doesn’t sound like much, it is a significant difference. It means 100 pounds of British cast iron weighs 106 pounds while the same volume of Confederate cast iron weighs 100 pounds.
Thus, if we compute the volume of a 2.75-inch Whitworth bolt and multiply it by the weight of CSA or British cast iron, we can accurately determine the weight of a new, complete solid bolt and identify each by their weight.
To compute an accurate volume, we must select the identical British Whitworth the Confederate’s copied. The British pattern copied by the Confederate’s is shown in Kerksis and Dickey (page 233) at 13.0 pounds; Dickey and George 1980 (page 291) at 12.625 pounds; Dickey and George Revised (1993), page 329 at 12.625 pounds; and Melton and Pawl (page 234) at 12.6875 pounds. Note that none of these authors’s noted a lathe dimple on the nose and all recorded the weight at over 12.5 pounds, closer to 13.0 pounds. This is because all of these specimens are actually British. A Confederate specimen of this pattern cannot weigh over 12.5 pounds.
The only way to accurately determine the volume of any projectile is to place it in water and compute the amount of fluid it displaces. The amount of water displaced in milliliters can be converted to cubic inches of iron. The author methodically conducted these delicate computations using actual specimens.
Without putting everyone to sleep, this writer took the British specimens noted above and compared them to what he determined was a Confederate reproduction. They were very close to being identical, with the Confederate specimen having slightly greater windage for safety purposes.
Liquid displacement testing by the writer revealed the volume of the British 2.75-inch bolt is 49.52 cubic inches. When this is multiplied by the weight of one cubic inch of British cast iron, it reveals a new specimen would weigh 13.3 pounds. The writer believed he had made a miscalculation until he noted General Abbot recorded an identical specimen weight in Siege Artillery in the Campaigns against Richmond, 1866, Plate 6, Figure 75. General Abbot noted his specimen weighed 13.3 pounds. This writer had previously thought this was a typographical error, but it became immediately clear that General Abbot was correct. When noting the British specimens quoted above, all were closer to 13 pounds than the lighter Confederate projectiles the writer has examined. We must note that all projectiles have lost weight due to either burial or oxidation (just exposed to air) because over a period of 140+ years, almost ALL specimens noted to date have lost some of their original weight.
The Confederate reproduction is about 49.2 cubic inches, but when this is multiplied by the weight of one cubic inch of Confederate cast iron (0.253351 lb), it produces a weight of about 12.46 pounds. As simple as this test is, relics that have been buried in fresh water soil or cleaned have often lost 4 to 8% (or more) of their original weight. This makes it extremely difficult to determine the bolt’s original weight, but we can get close enough to make some judgments.
Thus this writer’s conclusion is that any bolt that weighs over 12.5 pounds has to be British and those weighing less than 12.5 pounds are likely Confederate.
Further, any bolt that has a dimple on the nose is a Confederate reproduction. None of the British specimens examined to date had a dimple on the nose and without regard to their condition, have weighed more than 12.5 pounds with most approaching 12.75 pounds or more. To further confuse the issue, some Confederate specimens do not have lathe dimples on the nose, but they all weigh less than 12.5 pounds, suggesting the Confederates either modified the manufacturing process to eliminate the need for a nose dimple or Fayetteville and Tredegar had different manufacturing methods.
The Confederates also produced another bolt of a slightly different pattern and this can be identified by a slightly different nose contour. The writer recovered one at Petersburg, but unfortunately none of the books to date feature a picture of this projectile. This writer has done liquid displacement testing on his specimen and confirmed it is made of very crude Confederate cast iron.
This has been a very long-winded explanation, but this writer is confident of the conclusions reached. If anyone wants to discuss this further, please feel free to contact me at ColJFB@aol.com. Please put Whitworth as the subject so I don’t delete it as spam mail. I’m very sensitive to how controversial this subject is and I don’t want to get in a position where I have to contradict any of the information presented in the past by the true experts in publications, books or on this forum.
I genuinely hope this information will help in the future identification of Confederate manufactured bolts versus those imported from Britain. My experience to date is there are more Confederate specimens in collections than British projectiles. This is a tribute to the ingenuity of the Confederate Ordnance Department that managed to provide ammunition to an Army that was fighting against all odds. I have only found reports reflecting a need for replenishment of expenditures. I’ve not found a single report or read anything that indicated any battle was lost due to a lack of artillery ammunition.
I salute the Confederate Ordnance Department for accomplishing the near impossible.
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Thank you very much for your interesting research, and sharing it with us first here on the forums. We salute you !! DK
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Col. John,
A most comprehensive analysis. so dimples are out and true weight is in.
thank you sir for participating .
All the Best,
John aka Bart
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Colonel John, That is a wonderful post. Thank you for your research and hours of hard work. Your conclusion makes eminent sense. I would not have guessed that the quality of the carbon iron would make such a large difference in weight. Your statement that most battlefield Whitworths are actually Confederate manufacture is fascinating. As soon as I get home, I will weigh my Whitworths and reclassify them as needed.
Just a great piece of work. Scott in Atlanta
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Way back at the start of this discussion, Scottfromgeorgia wrote:
> What's the consensus on this - are these lathe dimples [on a Whitworth Bolt's nose] really indicative of Confederate manufacture?
The answer is no. The great majority of still-existing Whitworth Bolts were British-made -- and they have a distinct lathe-dimple on the nose.
ColJFB wrote:
> If anyone wants to discuss this further, please feel free to contact me at [_____].
Feeling the same concern my good friend ColJFB mentioned, about publicly contradicting well-respected experts, I contacted him privately to discuss certain points in my reply-post, below. So, readers, please be assured that he is not being "blindsided" by my reply.
He and I agree: We are "scientific-minded" Historical Researchers, seeking the Facts. We are pleased to work collaboratively to do so. The quest is not about ego or status.
Before I post the observations I discussed with ColJFB by telephone, let me also publicly congratulate him for his groundbreaking proposal to rely on a Whitworth Bolt's precisely-measured weight for distinguishing CS-made specimens from British-made specimens.
The vast majority of Whitworth Bolts sold by Bannerman are British made, not Confederate. Apparently, Bannerman's initial purchases (1870s) were mostly the captured cargo of Confederate blockade-runners. (The US Ordnance Dept. had decided not to use Whitworth cannons, and thus had no use for those blockade-runner projectiles either during the war or after.) Afterward, toward the the latter 1800s, the British government sold off its obsolete stocks of Whitworth cannon projectiles, and Bannerman purchased many of them. The latter is why Bannerman's famous annual mail-order catalogs contained Whitworth "detachable-nose" Case-Shot as well as Bolts.
About the greater weight:
ColJFB's diligent research that British cast-iron was heavier than US/CS cast-iron is impressive, and much appreciated ...but it is not relevant in this case. Whitworth projectiles were not made of cast-iron. According to Sir Joseph Whitworth himself, British-made Whitworth projectiles were of "mild steel."
The Specific Gravity of steel is 7.8, and "antique" cast-iron was 7.1 (see the US Ordnance Manual of 1861). Modernday cast iron is closer to 7.2 (see various "Specific Gravity of Metals" charts, online.)
When we precisely weigh various Whitworth Bolts to determine whether they are CS-made or British-made, any such tests must take into account the varying lengths of them ...which of course will significantly affect their weight.
Checking various books shows various Whitworth 2.75"-caliber Bolts, ranging in length from 8-&-7/8-inches (8.87") up to 9.5-inches. (One in the Melton-&-Pawl book says 9-&7/8" ...but I think that is a typo, which should have said 8, not 9, because its reported weight is almost exactly the same as the fully-1-inch-shorter 8.87" specimen shown in the D&G book.)
Apparently, the British-made Whitworth 2.75"-caliber Bolt came in two significantly-different lengths... 8.87 and 9.5-inches. I think the 9.5" version is the later of the two. Also, the later British model's flat base diameter is wider, being greater than 2.0 inches, whereas CS-made specimens' base-diameter is 2.0" or less. I posted that observation years ago, in an internet-forum which unfortunately seems to no longer exist.
Thus, in addition to ColJFB's groundbreaking proposal of relying on precisely-measured weight, the flat base's diameter may be another clue for distinguishing British-manufacture from CS-manufacture 2.75"-caliber Whitworth Bolts.
Also, in the 25 years before I read ColJFB's weight-measuring method, I relied on measuring the main body's diameter (across the "flats"). As I mentioned in the D&G 1993 book, on page 333, the British Whitworth artillery projectiles were made to be used as breechloading ammunition, whereas the CS-made ones were to be muzzleloaded. The CS Ordnance Dept. saw many incidents of Whitworth breech-locking failure, so it ordered the breeches to be locked down and ammo to be loaded from the muzzle. Therefore, CS-made Whitworths tend to be smaller in diameter ...from 2.69 to 2.72" according to measurements I've made over the years. British specimens I've measured have tended to be 2.73 to almost 2.74-inches.
In conclusion, I am asking this forum's members to perform (and report) precise measurements of their collection's 2.75"-caliber Whitworth projectiles in four ways (plus one other feature):
1- diameter of the main body (across the "flats")
2- diameter of the flat base
3- length
4- weight
5- presence or absence of a lathe-dimple.
Working collaboratively, we collectively can produce "the definitive guide" for reliably determining British-made and CS-made 2.75"-caliber Whitworth Bolts.
Regards,
Pete
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One thing that wasn't lost from the old forum were the articles.
Here is a good one Jack Melton wrote on Whitworths, albeit not this topic specifically:
http://thomaspublications.com/civilwarprojectiles/articles/12pounder_Whitworth_Bolt.htm
The rest of the articles can be accessed via:
http://thomaspublications.com/civilwarprojectiles/articles.asp
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This question is for Jack Wells or anyone that has more than one bolt. I was looking at my bolts today, and I noticed that the ends of the flats were different. I have one bolt that is crudely cast with air bubbles and divets in the iron [ or mild steel ]. I don't think Mr Whitworth would ever let his quality inspectors ship this out as crudely cast as it is, so I lean to think it is CS manufacture.
My other bolt is sharp edged and perfect without a flaw in the casting, this lends me to think this is British manufacture. Plus, I have a detachable nose 2.75 also, defiantely British manufacture. Both of these have very 'sharp' and pointed ends to the flats. In contrast, my rough probable CS bolt has rounded ends to the flats. Distinctly different.
So my question to Mr. Wells or anyone that has multiple bolts : do you see a difference in the flats as I do ?? By the way, both have lathe dimples in the nose..........
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I placed my projectiles ,except for a dissasembled "Shrapnel" shell in storage when we moved some 14 months ago and it's a five (5) drive for me to pick them up,but will try to get down to Wilmington,
and pick them up within the next two (2) weeks,when will be dependent on what ever Range or Museum dutys I may be task with,so bear with me
Jack Wells
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I posted the partial results of a study I made to determine whether a 2.75-inch Whitworth bolt is of British or Confederate origin based on its weight, the volume of the projectile as determined by liquid displacement and its comparison to the weight of British cast iron versus Confederate. I conducted this study because at one of the Richmond shows six of the most knowledgeable “experts” that I know were debating whether a 2.75-inch Whitworth bolt was of British or Confederate manufacture. The bolt had been cleaned up so measurements across the flats and angles were inconclusive. It had an alignment “dimple” on the nose, a rough base, was 9.4-inches in length and weighed 12.24 pounds. Based on my study, I made certain conclusions that Dave the Plumber ask me to share on this forum.
My good friend and distinguished colleague Peter George has taken exception to my findings. When I made this post I went out of my way to avoid a conflict of opinions and asked anyone that wanted to discuss my findings to contact me. I did this because I had genuinely hoped that I could avoid going on this forum and going head-to-head with the World’s experts on Civil War ordnance over a simple liquid displacement test finding. It appears that I have failed.
Pete is indeed one of the World’s experts along with Jack Melton, Jack Bell and a few other exceptionally knowledgeable individuals. I wish that I had their “hands-on” knowledge. In fact, Pete contacted me within a few hours of my post to express this friendly concern. I appreciate this as our friendship goes back thirty years to when he had his relic shop in Fredericksburg. In fact, he has made a tremendous contribution to my encyclopedia and I couldn’t be so close to publication if he had not shared his data base with me.
When he called we had a congenial conversation and I noted his exceptions and attempted to explain my findings. Unfortunately, it appears that I have failed.
While I appreciate his comments, I must reply to defend my displacement study as I’m quiet certain that it will survive after being put under a microscope and the “spot-light” of justice.
Pete said that the “vast majority” of Whitworth bolts sold by Bannerman’s are British made, not Confederate.” I cannot dispute this other than to note that most collectors believe pristine specimens came from Bannerman’s as I stated. Based on displacement testing, I concluded that those that have or don’t have “dimples” on the nose that weigh less than 12.5 pounds are Confederate because I haven’t found a CSA specimen that is about 9.4-inches in length that weighs more than that. They can’t because of the lighter specific gravity of CSA iron. You can’t get ten pounds of beans in a five pound bag. The volume of the Confederate bolt is a limitation. The British bolt of this size (9.4-inches) is significantly heavier, about 13.3 pounds when new. Page 329 of Pete’s revised 1993 edition shows a short British bolt (8.87-inches in length) that weighs 12.625 pounds, supporting my findings that British bolts weigh more than 12.5 pounds... even the short pattern. If the additional one-half inch was added to bring it to 9.4-inches, Pete’s specimen would weigh what General Abbot recorded in his book. Holley (page 34) states the 2.75-inch shell that is only 7-inches in length weighs 12.156 pounds (including fuse and bursting charge) illustrating just how heavy British cast iron is compared to other services. Unfortunately, I think the length is a typo and should read 9.0-inches.
In addition, I didn’t say Bannerman’s didn’t sell British bolts, because they did. But based on empirical data and the collections I have visited it appears most of the 2.75-inch bolts in pristine condition that I have seen weigh less than 12.5 pounds so you can draw your own conclusions as to whether these were sold by Bannerman’s and/or the ratio of their 2.75-inch bolt sales.
I didn’t say all 2.75 bolts are identical and I meant to be clear that the specimens that I conducted liquid displacement tests on were relatively identical in length and volume. I acknowledged the windages were different with CSA Whitworth’s having more windage for reasons of safety.
Pete states that “…Bannerman’s initial purchases (1870s) were mostly the captured cargo of Confederate blockade-runners.” While I cannot dispute this logic (they somehow ended up at Bannerman’s), my research has been unable to document whether they came off blockade runners, from surplus federal stocks, from captured Confederate stocks, from Whitworth’s worldwide sales as the system became obsolete or a mix of all sources. I would appreciate it Pete, if you could provide the references supporting your conclusion that Bannerman’s stocks were mainly from captured blockade runner cargos and not also from captured Confederate stocks or from federal or foreign sales surplus. I would like to include those references in my encyclopedia.
Pete also states “toward the later 1800s, the British government sold off its obsolete stocks of Whitworth cannon projectiles, and Bannerman’s purchased many of them.”
“A Treatise on Ordnance and Armor, by Alexander L. Holley, D.Van Nostrad, London, 1865, reveals the British government adopted the Armstrong system as standard, tested the Blakely and Whitworth systems, but never adopted either of them. Whitworth was strictly an export rifle, sold world-wide to multiple nations. This is documented on pages 46-47 and pages 863–870. Page 36 specifically says, “…neither the gun nor the rifling of Mr. Whitworth’s have been yet adopted by the British government…” Numerous other sources state the British Government rejected Whitworth’s design as well (check Joseph Whitworth in “Wikipedia,” The Gun, W. L. Ruffell, and other sites). Since the British government rejected Whitworth’s design in the early 1860s, I would be curious how Pete concluded the British government sold off stocks of a projectile they never purchased for a system they never adopted “toward the later 1800s.” I would again appreciate it Pete, if you could provide the references from your research to support your statements as I would also like to include them in my work, as previously undocumented Whitworth sales to the British government.
Pete agrees with me that British cast-iron was heavier than US or CSA cast-iron, but he states “…it is not relevant in this case.” In my view, IT IS THE MOST RELEVANT FACTOR IN MY STUDY! How can you make an absolute conclusion of provenance unless you identify the origin of the cast iron (or steel), given they are so different?
There are many 2.75-inch bolt variants due to replication of the pattern, manufacturing techniques, quality control, and production line changes. It’s difficult to sort them out without using the known weights of British and Confederate cast iron. The weight of British cast iron is unique, fully documented and is not the specific gravity of the metals that Pete mentions.
Pete states British made Whitworth projectiles were made of mild steel. I won’t dispute this, but my tests confirmed the specimens I examined were made of British cast iron at 0.2685743 pounds per cubic inch. Mild steel is even heavier than British cast iron and weighs up to 0.284 pounds per square inch.
I think Pete’s statement makes my case stronger. Both British cast iron and mild steel weigh more than Confederate cast iron. A British bolt made of mild steel, the size I studied (49.52 cubic inches) would weigh up to 14.06-pounds, making it even easier to identify by weight. How can we say weight isn’t relevant? These projectiles have volume limitations due to their size and weight becomes the critical factor in making difficult identifications.
Again, one must examine the weight of the projectile and divide it by its volume in cubic inches to determine the origin of the metal. It just happens that the patterns of Confederate 2.75-inch bolts that I’ve measure do not weigh over 12.5 pounds because of their size. Furthermore, I’ve not seen one with an “alignment dimple” that weighed over 12.5 pounds. If someone has one, please let us know. This would be significant information.
Pete’s post goes into the various lengths, diameters, and diameter of the flats of British and Confederate Whitworths. I have these measurements in my Encyclopedia for the various variants, with the proper references. I most note that Pete states “…later British model’s flat base diameter is wider, being greater than 2.0-inches, whereas CS-made specimens base-diameter is 2.0” or less.” Some of the Confederate specimens I’ve seen, including the one I found at Petersburg have a base diameter of about 2.15-inches, indicating some exceptions exist.
Conducting accurate measurements are a good indication of the pattern and origin and are sufficient for the collector that doesn’t want to conduct displacement testing. I don’t dispute the value of measuring bolts and weighing specimens. I do it and it’s very informative. Holly states the British specification (page 34) for the 2.75-inch bolt is 2.73635-inches across the flats and 2.97735-inches across the angles.
Unfortunately, this is not absolutely conclusive because many specimens have been over-cleaned and are smaller than their original measurements across the flats and angles. It’s easy to remove 0.02365 inches during cleaning, or increase the projectile’s diameter by applying a protective coating.
At no point in Pete’s post did the word “displacement” appear so I must assume he places no value on displacement testing. My conclusions are based on the weight of the cast iron per cubic inch and this can only be determined by liquid displacement. I developed very accurate mathematical formulas to computer model projectile weights, but they aren’t totally accurate on small projectiles because of slight variances in projectiles. The only way you can accurately determine the volume of a projectile is to carefully determine its volume by liquid displacement.
Let me explain how to do this. Take a container just larger than the projectile and place the projectile inside. Add water using a scientific beaker and measure the exact amount of water (in milliliters) it takes to flood the container to the top of the bolt. Carefully record this value and put a mark on the container so you can refill it to that mark.
Remove the bolt, empty the container, dry it to remove all water and refill it with water to the precise mark. This value is greater so we deduct the first value (projectile in water) to determine the volume of the projectile in milliliters of water. This liquid value is converted to cubic inches to reveal the volume of the projectile.
The projectile is then weighed on a scientific scale or postal scale and its weight divided by the bolt’s volume, in cubic inches, to reveal the metal’s weight per cubic inch to five digits.
Now I repeat. If that value is approximately 0.253351 lb per cu inch or less, it’s likely Confederate cast iron. If that value is about 0.2685743 lb per cu inch, it’s British cast iron. If the weight is over 0.2685743 lb to 0.284 lb per square inch, it’s a form of pure cast iron or steel, but both are British. If the measurements and weighs are correct and the mathematics is done correctly, it produces an indisputable weight per cubic inch of iron! This isn’t “rocket science.” It’s pure physics and it’s difficult to argue with the numbers these tests produce.
I haven’t found any 2.75-inch bolts made of steel, but I don’t doubt they exist. But if they do, they will be even heavier than the 12.5 pounds that I have used as the general rule for determining whether the origin of the bolt is British or Confederate.
So based on the density of Confederate cast iron and the volume of a 9.4-inch, a Confederate 2.75-inch bolt cannot weigh more than 12.5 pounds and a British bolt of the same caliber and pattern has to weigh significantly more. General Abbot’s was 13.3 pounds. Based on this information, I rest my case.
So I agree with Pete’s request for measurements to study this further. However, I ask members to conduct liquid displacement tests on their 2.75-inch Whitworth bolts, if possible, to determine the projectile’s volume. This would be a more positive proof of origin.
If that’s impractical, I ask anyone with an accurate scale to find a 9.4-inch, 2.75-inch Whitworth bolt that has an “alignment dimple” on the nose that weighs more than 12.5-pounds. I don’t know whether the British used an alignment “dimple” and this test will tell us if they did.
If one can’t be found, it might indicate this was unique to Confederate production methods at one of the facilities that made them. Worse yet, it could indicate Bannerman’s purchased 2.75-inch bolts abroad from the countries that phased the Whitworth system out as obsolete. There is no reason to discount the idea that countries that purchased the Whitworth system didn’t produce their own ammunition! Based on the specific gravity of the cast iron they used it could produce results completely inconsistent with the weights of British and CSA bolts. Whitworth specimens that have no Civil War provenance continue to be imported to the US because of their high value and regularly show up on the collector’s market.
I only ask that you make certain that your scale is accurate because we are at the stage where we are “dynamiting mouse turds” and accurate weights are required to evaluate British versus Confederate 2.75-inch Whitworths.
Respectfully, John B.
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1- I think Pete may have seen some copys of an Army publication,that I sent the late Tom Dickey
ref.Bannerman buying surplused Whitworths,that had been captured on "in bound
Blockaderunners" along with other items being sold off.
2- If my ancient mind remembers correctly the inf. was in an 1870's "Army Navy Journal" which I
found in the National Archeives back in the early 1970's. Again I could be wrong on the ref. I've
listed.
3- Not "Dimple" related,butwhat happened to the six (6) Btry. of Whitworth Guns and mmunition,that
were sent to the U.S. Gov. by U.S. Citizens living in Enghland ? Abbot took four of the Guns to use
as countery Btry. weapons,were the Guns and remaining ammo. sold as surplus?
4- Have enjoyed everyones post on the subject.
5- Now to find an accurate scale to find the weight of my Bolts.My bath room scales are off as I
couldn't be that heavy.???
Jack