V0.21 1905 Gatling Gun with Carriage

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ppemawm
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V0.21 1905 Gatling Gun with Carriage

Post by ppemawm »

I have been working on this project off and on all summer and have finally finished it at least as far as the original drawings allow. Gatling guns have always intrigued me with their incredibly complex load, fire, and extraction mechanisms. Drawings for this project are available at https://archive.org/details/GatlingGunBlueprints and http://gunneyg.info/html/AOPCatalog.htm.

However, there are no assembly drawings or bill of material AFAIK so you are a bit on your own. I only had one part left over and one that I did not know how to model or assemble due to lack of detail. Other than that the model is authentic to the original from 1905. The model was created with V0.21 PartDesign and assembled with Assembly4 V0.12.4.

A few screenshots with brief comments are as follows:

This view is shown with the hopper and magazine in the open position with a transparent breech casing.<br /><br />The Assembly4 Model is composed of several nested sub-assemblies.  All of the individual bodies are saved in the Parts folder of their respective sub-assembly.  <br /><br />For this project I opted to have many more simple sub-assemblies with fewer parts each with more nesting at the top assembly level.  Seems like a simpler way to go as you are modelling.  The files shown in the Tree are all of the sub-assemblies, some of which are nested themselves.
This view is shown with the hopper and magazine in the open position with a transparent breech casing.

The Assembly4 Model is composed of several nested sub-assemblies. All of the individual bodies are saved in the Parts folder of their respective sub-assembly.

For this project I opted to have many more simple sub-assemblies with fewer parts each with more nesting at the top assembly level. Seems like a simpler way to go as you are modelling. The files shown in the Tree are all of the sub-assemblies, some of which are nested themselves.
Capture24.jpg (396.35 KiB) Viewed 1963 times
For an idea of scale the carriage wheel is about 54 in. in diameter.  The gun assembly alone weighs 245 lbs.  The total weight is reportedly about 600 lbs including the carriage and magazines.
For an idea of scale the carriage wheel is about 54 in. in diameter. The gun assembly alone weighs 245 lbs. The total weight is reportedly about 600 lbs including the carriage and magazines.
Capture24a.jpg (405.74 KiB) Viewed 1963 times
A close up of the breech, lock, and barrel assembly.<br /><br />The magazine holds 40 rounds of 50 caliber ammunition and weighs about 16 lbs.
A close up of the breech, lock, and barrel assembly.

The magazine holds 40 rounds of 50 caliber ammunition and weighs about 16 lbs.
Capture25.jpg (362.66 KiB) Viewed 1963 times
The lever on left allows you to extract each of the 10 lock tubes to inspect the firing pin, spring, and extraction mechanism.<br /><br />The center knob is for adjusting end play on the shaft.<br /><br />I am not quite sure what the knob on the right is supposed to do but it is attached to the cocking mechanism perhaps for fine adjustment or releasing it if jammed.
The lever on left allows you to extract each of the 10 lock tubes to inspect the firing pin, spring, and extraction mechanism.

The center knob is for adjusting end play on the shaft.

I am not quite sure what the knob on the right is supposed to do but it is attached to the cocking mechanism perhaps for fine adjustment or releasing it if jammed.
Capture26.jpg (369.37 KiB) Viewed 1963 times
This image shows the detail of the breech with its 10 lock tubes.  Each of the lock tubes contains a firing pin, spring, and extractor which grips and releases the cartridge.  The complete sub-assembly rotates. <br /><br />The stationary cam which positions each lock tube and cartridge axially as the hand crank is rotated is not shown.  The available drawings do not include enough detail for a good model of the cylindrical cam.<br /><br />As the lock assembly rotates, the cam also forces the firing pin through the cocking mechanism which compresses and releases the loading spring to fire the bullet.
This image shows the detail of the breech with its 10 lock tubes. Each of the lock tubes contains a firing pin, spring, and extractor which grips and releases the cartridge. The complete sub-assembly rotates.

The stationary cam which positions each lock tube and cartridge axially as the hand crank is rotated is not shown. The available drawings do not include enough detail for a good model of the cylindrical cam.

As the lock assembly rotates, the cam also forces the firing pin through the cocking mechanism which compresses and releases the loading spring to fire the bullet.
Capture27.jpg (385.04 KiB) Viewed 1963 times
'
You can find several YouTube videos of various antique gatling guns in operation. This one was especially useful to me to better understand how the the lock assemblies and cam operate: https://www.youtube.com/watch?v=t9qEToARkIM starting at 1:10.

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.21.30716 (Git)
Build type: Release
Branch: master
Hash: cbd19631428f1d9eb4faae30220551608a648589
Python 3.10.6, Qt 5.15.4, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3
Locale: English/United States (en_US)
Installed mods: 
  * Assembly4 0.12.4
  * fasteners 0.4.15
  * freecad.gears 1.0.0
  * QuickMeasure 2022.10.28
"It is a poor workman who blames his tools..." ;)
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M4x
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Re: V0.21 1905 Gatling Gun with Carriage

Post by M4x »

Wow, all those details! Thanks for sharing! I see a lot of ours invested in that model(s).

edit
I've two more questions:
  • Did you upload the model somewhere?
  • How do you color your models? Do you pick each color by hand or what's your workflow here?
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ppemawm
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Re: V0.21 1905 Gatling Gun with Carriage

Post by ppemawm »

Thank you for your comments.
M4x wrote: Fri Nov 04, 2022 4:35 am I see a lot of (h)ours invested in that model(s).
I downloaded the drawings July 30 and have spent about 2-3 hrs/day on FreeCAD since.
M4x wrote: Fri Nov 04, 2022 4:35 am
I've two more questions:

Did you upload the model somewhere?
How do you color your models? Do you pick each color by hand or what's your workflow here?
I have not. If you have any further interest in the model please PM me. There are 20 sub-assembly files plus the top assembly.
I probably cannot share the carriage model since those drawings are for sale and likely copyrighted.

I manually color the bodies (not the features) as I create each model using the View > Appearance feature.

My general workflow using The Assembly4 and PartDesign workbenches is as follows:

1. Create an Assembly4 file, Model, and Body(s) in the Parts folder which includes a default LCS in each Body for assembly.
2. Double left click the Body which takes you to PartDesign to create first sketch.
3. Locate first sketch on an mating interface which automatically locates the LCS for the body for assembly. Create features.
3.1 Add LCS's and/or Hole Axes at each additional assembly interface as you model. Attach these to the sketch that creates the assembly interface.
4. All bodies are located at the global origin while modelling. If drawings are not available I assemble the body before creating any features.
5. Assembling the body allows you to work in-context which I prefer, i.e. top down. Select the body link not the original body in the Parts folder.
6. I tend to put all bodies for a sub-assembly in one Assembly4 file since it is easier to manage and distribute the files for larger projects.
6.1 You can still re-use these bodies in other projects but the sub-assembly file has to be open. Or, you can save them to their own file for re-use.
6.2 If there are many purchased parts or .step files I usually put all those in one file in an Assembly4 part container for each.
7. All parts that must be able to move should be in the same sub-assembly which makes it easier (possible) to animate the model to check clearances, etc.
7.1 E.g. sub-assemblies for stationary, rotating, and reciprocating or articulating bodies.
8. I usually assemble the sub-assemblies in the top assembly as I create them in the same sequence as you might assemble them on the bench.

Other than that it is just patience and dogged persistence.
"It is a poor workman who blames his tools..." ;)
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mhalil
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Re: V0.21 1905 Gatling Gun with Carriage

Post by mhalil »

Excellent, I love it.
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