SJSoane

I just experimented with Fusion 360 after working with TurboCad Mac for a few years (the latest upgrade for TurboCad includes CAM, I understand; my version does not). Fusion is definitely more elegant and powerful. It is still not clear to me from the website that the free license is renewable, and so I am a little hesitant to invest a lot of time into creating models with this if it eventually goes away. It has extensive and free training videos. Mark

Hi Alan, I just sent a PM.

Hi Paul, Now that is an interesting idea. The highest quality one would cost $26.40, maybe an interesting investment to see how it could turn out. I have heard that the best still have slight lines where the layers are formed, but cleaning up just one for a master would not be as dreary as cleaning up 74! I will reflect on whether this gives me anything better than just manually turning a master on the lathe, as I did before. Mark

Thanks to the members on the CAD threads, I tried using Autodesk's Fusion 360 software to build a second version of the cannon, and it was very high quality; I also converted the earlier model with the insignia to the STL file type needed for 3-D printers, as shown below. But, it all came to nothing when I got the quote for 3-D printing at an online service. For the 74 guns it was going to be $556 for the lowest level of refinement, up to $1950 for the highest level of refinement. Way too much for a retirement budget, especially since I have been told that they will still show the layers as they build up. 3-D printing is no longer an option. On to other ideas. I realize that I was attracted to this because the digital model shows all of the wonderful, nuanced detail of the cannon itself, at a scale that looks real. But when this is shrunk down to 3/16" scale giving a 2" long cannon, most of the nuance disappears. I was disappointed to lose what I know should be there. Perhaps the best thing is to print out a large image of the digital cannon and pin it on the wall of my shop, to remind me what the model cannon represent! Mark

I played with Fusion this weekend, tried drawing my cannon project. It takes a little getting used to, but it did create a high quality model. Mark

a little more research on STL files today, and I found a much finer setting. I put all setting at 0 except normal deviation which I put small at 2.25. Putting this at 0 really messes it up, for reasons I don't understand. But this file size is 24 MB. I will have to find out the max resolution for the printing company tomorrow. Mark

I just came across this thread while posting another topic in this area. After struggling with some of the idiosyncrasies of TurboCad for Mac, I am intrigued by the videos for Fusion 360 a number of you have pointed to. But I don't find on the Autodesk website how much the subscription is after the free trial period, for hobby use. Has anyone subscribed to this, and can you tell me how much it costs you? Mark

Good suggestions. Here is a screen shot of the higher resolution file. Mark

Nice, Alan, I upped the surface deviation from 0 to 45. Much better. Thanks for the suggestion! It turned into a 2.2 MB file, so too big to show here. Mark 32 gun for export deviation surface to 45.stl

druxey, I was thinking the same thing!

I just converted the file to STL, which is what Shapeways asked for. But it is quite faceted. Is this the best I can expect for a 3-D file? I saved it as a Binary file, although there was a choice for an ASCII file. There was also a choice for number of facets in the Binary option, I have shown the default that I chose. Apologies for the dumb questions; this is my first ever effort at 3-D printing, not quite sure where I am heading. Best wishes, Mark

Thanks to great help from our colleagues on the CAD section including Alan, I managed to create the king's insignia in the digital file. I will try getting a 3-D print of this, just to see the quality. Although I have heard that 3-D printing is not quite up to snuff at this scale. And while waiting for that, I will continue with the duplicator... Mark

Aha! Got it. Not quite sure how. I had to create a cover skin of the line drawing, then pull the skin into a solid, then subtract from it a female mould of the barrel shape + ¼" radius. Then add to the barrel. druxey, if I can figure out how to profile this with rounded edges, I will come out of retirement and start a CAD business!☺️ But thanks for the photo; it is great to see what we are trying to approximate here. Mark

More work, it seems I have projected the walls, but not the top surface. At least I figured out how to make a female mould of the curve above the insignia, which I used to subtract from the top of the insignia. Now I just need to find out why I am not creating a top surface...

Thanks, everyone, for these helpful suggestions. I am making a newbie mistake somewhere. However I try to extrude or project the insignia, I get an ill-formed solid, as seen below. Turbo Cad Mac is not very good at identifying the problem areas. When I first attempted to create a solid out of the line drawing, it said there are duplicated or overlapping curves and will not proceed. Unfortunately, sometimes it showed me where the offending problem is, sometimes not. I thought I had fixed them all when a tool like extrusion allowed me to proceed instead of calling an error. But when I proceed, I get these ill-formed solids. This image below is based on a drawing of control point splines. I have tried converting this drawing to interpolate splines, simple curves, etc. but the solid is still ill-formed. I will keep trying edits to see if I can at least get a clean solid from which to try the good suggestions above. I just wanted you all to know where I was with this.... Mark

Pat, thanks, I was wondering about that. I will have to see if I want to invest in an upgrade. I am not sure how far down the road I am going with this 3-D printing quest as it gets more complicated and expensive! I will contact TurboCad and find out more. Thanks again, Mark

Thanks, Alan, I will look for something like that in TurboCad... Mark

I am working on a digital file for 3-D printing cannon for my Bellona project (in the scratch-built section). I am using TurboCad for Mac Deluxe version 10. I have made the insignia a solid, as you can see below, but I can't figure out how to curve its upper surface to match the curve of the cannon. Also, how to merge the insignia into the cannon so there are no gaps or intersecting solids between the two. I assume this would be a bad thing when creating the file for the 3-D printer. Can anyone help with this? Best wishes, Mark

I am proceeding with fabrication of the cannon. I decided that this would be a good time to try a couple of strategies, to see which one gives the best results, and also to build my skills in a few new things. I will try duplicating from a template, reworking the casting I tried earlier, and 3-D printing. I have started making the the duplicating template, as seen below, and also creating the digital file for 3-D printing. Regarding the digital model, I am struggling with how to get the king's insignia to curve to the gun surface. I am using TurboCad for Mac, if anyone has a suggestion for doing this. I will also post this question in the CAD part of this website. Mark

Hi Alan, You are quite right. I went down this rabbit hole purely out of historic interest. The actual fabrication cannot likely reproduce the finer points. I have drawn my lathe duplicator cutter and follower to the size of the actual barrel, as below, and I can see that some of the moulding profiles will not be captured. But I guess like everything else in this model, at least I will know what SHOULD have been there! Mark

Hi everyone, Thanks to all of you, I now have a more sophisticated (that is, confused in a thoughtful way) understanding of the guns. Below are the guns I have tried drawing, starting with the Borgland gun in 1716, then the Armstrong pattern described by Muller in 1768, then the 1732 regulation based on Armstrong, and then Landman's 1788 instructions for an Armstrong. Let's compare these to the drawing in Falconer's Dictionary of the Marine, which I have taken as the closest image I have to the Bellona's time. The Bellona was launched in 1760, and the Falconer book was first published in 1769--although I have only seen editions from the 1780s, and so I cannot be absolutely sure that these drawings were original to the 1769 edition. Has anyone seen the 1769 version of Falconer, and are the drawings the same as in later editions? Assuming the Falconer drawings date from the 1760s, how do the various patterns compare to this? The Borgard has a cascable with two ovolo mouldings (half circles), but the Falconer has an ogee (S shaped). So the Bogard is out. The Landman has too fat a neck and button on the cascable; and the chase is too slender. So the Landman is out. The Muller version of Armstrong and the 1732 regulation based on Armstrong seem very similar. But the 1732 drawing shows a more complex cascable than the Falconer; the Muller version of Armstrong looks more like the Falconer drawing. And the Muller version has a longer, more slender neck than the 1732 pattern, more like the Falconer. I am therefore settled that the Muller version of Armstrong is closest to what I think the guns would have looked like in 1760. Siggi's excellent photos do challenge these drawings a bit. If I read Siggi's photo relative to the text correctly, the two cannon closest to us in the second photo are labeled as Armstrong patterns; but their muzzles have a more gradual slope than either Muller or the 1732 pattern is showing. Could these all be from a later date, like Landman's instructions from the 1788? The beautiful cannon on the red carriage looks a lot to me like the Landman instructions, with the more slender chase. I think this is the most handsome cannon of them all, but I will faithfully follow what I now think is most historically accurate for the Bellona, the Muller version of Armstrong. There is one last puzzling question, as I finish up drafting these cannon. The Muller instructions give the same width for all of the reinforce rings, ogees and astragal mouldings, no matter what the caliber gun. This doesn't seem consistent with the 18th century reliance on proportion relative to size, and they seem outsized on the smaller guns when I begin to draw them. I think I will proportion these down as a function of their relative calibers. Mark

hi everyone, After a break for the American Thanksgiving, I got back to the guns. Siggi, that link you provided above is very remarkable. It gives very precise instructions on how to draw an Armstrong pattern gun, quoting Isaac Landman's instructions from 1788. For those who haven't seen it, it has an interactive section where you can choose a gun size, and it will draw the gun for you. Well worth having a look at it. It gave much better information on details like the muzzle and cascable, so I tried his instructions. Interestingly, it creates a slightly different profile than the one I previously drew based on the one in Adrian Caruana's English Sea Ordnance showing the 1732 Regulation. Below, the one at the top is based on the Caruana drawing, the second is constructed from the Landman's instructions. Both purport to show an Armstrong pattern. But notice a couple of differences. The cascable is longer in the Landman, with a broader ogee (the S shaped curve) and the button has a larger diameter. Also, the chase tapers at a somewhat sharper angle than the two reinforce sections, giving the Landman gun a more graceful profile in my opinion. And the muzzle flare is a touch longer. It is beyond my research skill at this point to know which is the real Armstrong pattern, or whether it evolved over time while keeping the same name, or were these various authors looking back to different periods of development? The Landman profile does look like an effort to slim down the gun, which I understand was a desired effort through this period. I have appended the Falconer gun from the date of the Bellona, for comparison. Each step forward raises more questions! But that is the fun of this project. Mark

Bill, Thank you so much. This was a treasure to find. As it turns out it reproduced the diagram from the Muller treatise that was obscured in the Goggle digitalization. What a great magazine, looking quickly at some of the other issues and articles. Another day's research and drawing, and I discovered several interesting anomalies. First, as best I can tell, it appears that M.V. Brewington sometimes used shot diameter, and other times caliber, in calculating dimensions. So Hahn was following him. But the Muller description of the Armstrong proportions clearly works everything from caliber. Second, Muller's description of the Armstrong proportions does not correspond always with his own drawing to which he refers. He quotes the length of the cascable from the hind end of the base ring as 2 ¼ calibers, but the drawing is clearly shorter. And the drawing shows a ring on top of the neck, which I believed came much later in the century. So the more one digs into documents, the more mystifying it all becomes. All is finally laid to rest thanks to druxey, who was able to show me a drawing of the 1732 regulation, which I believe would be the guns on the Bellona in 1760. The shape corresponds to the guns shown on Falconer's Dictionary of the Marine, from the mid 1760s. So, for better or worse, this is the pattern I drew today. Now on to how I am going to make these. Mark

Alan, Very nice! Did you extrude the king's emblem? and how did you get it to curve? I am impressed! Mark

druxey, Something more like this? For the life of me, I can't remember where I found this years ago, to work from... Mark