Danish cannons for 3D printing

[Waldemar]

 

Again, Swedish digitaltmuseum, and again I am not able to provide a link for this specific plate, which I did not written anywhere when downloading, sorry. It must come from the Armémuseum resources.

 

 

[Waldemar]

 

I also calculated the weight of this barrel for possible verification of its dimensions. Reading the engraved weight markings as ‘XVI S(keppund) : X L(ispund) : [...] Markpund’ gives a result of approximately 2250 kg.

 

Admittedly, this is a fairly typical weight for a legitimate 24-pound cannon, yet this particular specimen, as a ‘drake’, is a relatively light cannon, being short and with thin barrel walls, so the result seems quite reliable.

 

Now, if you make a 3D model of this cannon (or even without it), you can calculate its volume and multiply it by the specific weight of bronze, which for a copper to tin ratio of 10:1 should be, say, between 8.5 and 8.6 g/cm³. This is actually the least reliable component of the calculation, as the actual alloy may have had different proportions and also other components as well. But these calculations are not difficult and are always worth doing in similar reconstructions.

 

[thibaultron]

Determine the length using the drawn bore width as a meteric.

[Nirvana]

Once I have my Elegoo resin printer up and running, I will certainly try out printing some cannons.

[TJM]

@Waldemar, it seems the canon is actually a 42 pounder: it is also depicted in the Grunth collection:

 

 

 

It is extremely short, only 13 calibres. Even a 24 pounder at 17-20 calibres would be longer overall, like it's neighbors on the page above. 

 

But it seems the 42 pound designation on the Swedish drawing is actually the Danish poundage.

 

The search for a C4 36 pounder continues! 😅

 

Edited yesterday at 06:09 AM by TJM

[Waldemar]

 

4 hours ago, TJM said:

@Waldemar, it seems the canon is actually a 42 pounder: it is also depicted in the Grunth collection:

 

No, please let me explain how Grunth converted a Danish 36-pounder cannon into a Danish 42-pounder cannon, or rather how he did not reconvert Swedish 42-pounder to the Danish 36-pounder.

 

First of all, Grunth's beautiful drawing is a redrawing of the barrel from the Swedish inventory drawing I showed earlier. However, Grunth completely lost track of his calculations because he took the Swedish barrel weight markings for the original Danish ones, and as a result, he also used Danish units of measurement instead of Swedish ones. And in general, he should have known, but did not know, that the weight of Danish barrels was not measured and marked in skeppund, lisfunt and pund, but just in pounds, then perhaps he would not have made his mistake.

 

The barrel is marked with the weight: 16 skeppund : 11 lispund (again: this is not the Danish way, but the Swedish way of measuring the weight of cannon barrels).

 

Correctly, according to Swedish units of measurement, this translates to:
16 x 136 kg + 11 x 6.8 kg = 2250 kg, or
16 x (400 markpund) + 11 x (20 markpund) = 6620 Swedish markpund

 

Incorrectly, according to Grunth:
16 x 160 kg + 11 x 8 kg = 2648 kg
16 x (320 Danish pounds) + 11 x (16 Danish pounds) = 5296 Danish pounds

 

In Denmark, skepppund and lispund were admittedly also used, but not in artillery to denote the weight of barrels.

 

Similarly, the calibre of 42 pounds written on the drawing was taken by Grunth directly without converting it to the Danish pound measure.

 

I believe that the same errors also apply to his other redrawings of Danish cannon barrels based on Swedish inventory drawings from 1670–1691.

 

 

[TJM]

I am not sure the logic holds. I agree that this is a possibility, but it relies on the assumption that Grunth copied the Swedish drawing. Do we know this is the case?

 

Grunth's drawing fits perfectly with a 42 pounder, from a bore size PoV. But of course that would be the case if the calibre is the only unit of measurement used to make the drawing. And he just assumed the 42 pounds was the Danish measurement.

 

Regarding the weight, I end up with close to 2500 kg based on the volume of a 3D modelled version. That is closer to Grunth's measurement for the weight, but somewhere in between your two calculations. 

 

I am not sure how to settle this definately.

Mind you, I am not saying you are not right here, I am just saying that I cannot prove it with the volume calculation.

[Waldemar]

 

2 hours ago, TJM said:

I am not sure the logic holds. I agree that this is a possibility, but it relies on the assumption that Grunth copied the Swedish drawing. Do we know this is the case?

 

On the first page of the 1860 edition, there is a note with the following content (but for some reason this note was omitted in the 1865 edition!):

 

In Danish:

 

Almindelig Bemærkning. Af de i denne Samling Tegninger optagne aeldre danske Metalkanoner existere ikkun de i Virkeligheden, ved hvilke saadant udtrykkelitgt er bemærket, uf de övrige haves der ikkun Tegninger, hvis Originaler findes i det kongelige svenske Krigsarchiv. Disse Originaltegninger, der skrive sig fra SIutningen af det 17de Aarhundrde, ere i Reg. Ien forsynede med Angivelser af Calibret, hvilke i det efterfölgende ere benytrede. De Angivelser af Godstykkelsen, Piecens Længde i Calibre og i Fodmaal samt Calibrets Störrelse udtrykt i Tommer og Linier, som nedenfor ere opförte, maae for de Piecers Vedkommende, hvoraf der kun haves Tegninger tilbage, kun betragtes som tilnærmelsesviis rigtige, idet de kun ere bestemte til at give er almindeligt Begreb om vedkommende Pieces Beskaffended.

English translation:

 

General remark. Of the older Danish metal cannons included in this collection of drawings, only those for which this is explicitly stated actually exist; for the rest, there are only drawings, the originals of which are found in the Royal Swedish War Archives. These original drawings, which date from the end of the 17th century, are provided with indications of calibre in the register, which are used in the following. The specifications of the thickness of the metal, the length of the pieces in calibres and in feet, and the size of the calibre expressed in inches and lines, as listed below, should be considered only approximate for those pieces for which only drawings remain, as they are only intended to give a general idea of the nature of the pieces in question.

 

Reproduction of the first page of the 1860 edition:

 

 

Nevertheless, for what I hope will be a final resolution, which I am also personally interested in, I will look for other drawings of captured Danish cannons in the Swedish artillery inventories from that period, and on which Grunth based his attractive drawings.

 

And there is still the possibility that I have been misled (again) by modern authors who, for the purposes of their publications, may have converted the weights of the earliest Danish cannon barrels into pounds, instead of leaving it in its original configuration or at least additionally referring to it.

 

 

[TJM]

40 minutes ago, Waldemar said:

 

 

On the first page of the 1860 edition, there is a note with the following content (but for some reason this note was omitted in the 1865 edition!):

 

In Danish:

 

Almindelig Bemærkning. Af de i denne Samling Tegninger optagne aeldre danske Metalkanoner existere ikkun de i Virkeligheden, ved hvilke saadant udtrykkelitgt er bemærket, uf de övrige haves der ikkun Tegninger, hvis Originaler findes i det kongelige svenske Krigsarchiv. Disse Originaltegninger, der skrive sig fra SIutningen af det 17de Aarhundrde, ere i Reg. Ien forsynede med Angivelser af Calibret, hvilke i det efterfölgende ere benytrede. De Angivelser af Godstykkelsen, Piecens Længde i Calibre og i Fodmaal samt Calibrets Störrelse udtrykt i Tommer og Linier, som nedenfor ere opförte, maae for de Piecers Vedkommende, hvoraf der kun haves Tegninger tilbage, kun betragtes som tilnærmelsesviis rigtige, idet de kun ere bestemte til at give er almindeligt Begreb om vedkommende Pieces Beskaffended.

English translation:

 

General remark. Of the older Danish metal cannons included in this collection of drawings, only those for which this is explicitly stated actually exist; for the rest, there are only drawings, the originals of which are found in the Royal Swedish War Archives. These original drawings, which date from the end of the 17th century, are provided with indications of calibre in the register, which are used in the following. The specifications of the thickness of the metal, the length of the pieces in calibres and in feet, and the size of the calibre expressed in inches and lines, as listed below, should be considered only approximate for those pieces for which only drawings remain, as they are only intended to give a general idea of the nature of the pieces in question.

 

Reproduction of the first page of the 1860 edition:

 

 

Nevertheless, for what I hope will be a final resolution, which I am also personally interested in, I will look for other drawings of captured Danish cannons in the Swedish artillery inventories from that period, and on which Grunth based his attractive drawings.

 

And there is still the possibility that I have been misled (again) by modern authors who, for the purposes of their publications, may have converted the weights of the earliest Danish cannon barrels into pounds, instead of leaving it in its original configuration or at least additionally referring to it.

 

 

Very nice information, thank you! 

 

This makes your theory quite plausible, I think!

 

 

[Waldemar]

 

Taking a closer look, I have found at least two dozen original drawings in the Swedish artillery inventory from 1670–1671 for the fortresses of Stralsund, Helsingborg, Malmö and Landskrona, on which Grunth based his redrawings. Here I show only some of the ‘duplicates’ I found.

 

Returning to the problem of determining the calibre of the cannons, and in particular the calibre of the Danish ‘42-pounder’ cannon: the original Swedish inventory includes cannons of various origins: Danish, Swedish, Imperial, from northern Germany, Russian and Polish-Lithuanian. All or almost all of them have their calibre marked on the Swedish drawings. However, it should be noted that these guns were not museum pieces at the time, but fully functional weapons currently in use. Therefore, the calibre of all these cannons must have been given in a uniform way, that is, in this case, according to Swedish units of measurement, and not according to the individual origin of these cannon barrels. And Grunth simply copied these calibres verbatim from the Swedish inventory without paying attention to this circumstance, i.e. without recalculating the values into Danish measurements.

 

Decide for yourself what you want to do with this information; I have just shown you the option available.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited 6 hours ago by Waldemar