Part 1
The guys over at FOSSCAD have challenged me to design a 3D printable revolver. Here are the goals that I set:
- Safe (failures will not harm the operator)
- Printable on a Rostock Max or smaller printer
- Minimum of type and number of non-printed components
- Double-action or double-action-only
- .22LR or larger caliber
- Ergonomic
- Simple operation
- Easy replacement of consumable parts
- Minimize resources required for consumable parts
- Durable frame
- 4+ shot capacity
- Easy acquisition of non-printed parts
That's a pretty long shopping list. I spent a lot of nights sketching on paper and modeling in Autodesk Inventor and came up with this, the PM522 Washbear revolver:
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It's a six-shot, 22LR, DAO revolver. All of the parts are 3D-printed with the exception of a roofing nail (to act as a firing pin), elastic bands (to act as springs), and the required amount of detectable metal in the grip. Here are some more views:
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Here's a look at the cylinder assembly:
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It's comprised of multiple parts. Each hole is its own rifled and chambered bore. The black bars shown are used to strengthen the assembly and help prevent delamination of the cylinder core (white).
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High-strength epoxy or acetone welding is used to bond these parts into a single unit. This unit is removed for reloading by removing a long pin from the front of the frame:
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Let's take a look inside the frame:
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Here we can see how the sear (grey) engages the striker (red). When the trigger nears its rearmost position, the bottom of the sear catches on a ledge inside the grip, which rotates the sear down and releases the striker.
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This cutaway reveals how the elastic bands are strung. It also shows how the firing pin is secured to the striker.
And finally we have the cavity in the grip to hold the detectable metal, in this case 8mm steel bars. After the metal is placed in the grip, the cavity is filled with epoxy and the grip cap is secured on top.
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Well there you have it. FP of FOSSCAD has again offered to print and test fire this revolver. I'll report back with the results.
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Questions? Suggestions? Let me know in the comments.
The guys over at FOSSCAD have challenged me to design a 3D printable revolver. Here are the goals that I set:
- Safe (failures will not harm the operator)
- Printable on a Rostock Max or smaller printer
- Minimum of type and number of non-printed components
- Double-action or double-action-only
- .22LR or larger caliber
- Ergonomic
- Simple operation
- Easy replacement of consumable parts
- Minimize resources required for consumable parts
- Durable frame
- 4+ shot capacity
- Easy acquisition of non-printed parts
That's a pretty long shopping list. I spent a lot of nights sketching on paper and modeling in Autodesk Inventor and came up with this, the PM522 Washbear revolver:
Hit the jump for a full breakdown.
It's a six-shot, 22LR, DAO revolver. All of the parts are 3D-printed with the exception of a roofing nail (to act as a firing pin), elastic bands (to act as springs), and the required amount of detectable metal in the grip. Here are some more views:
Here's a look at the cylinder assembly:
Since the firing pin is out of line with the cartridge when the trigger is not being pulled, this mechanism is drop-safe.
Let's take a look inside the frame:
And finally we have the cavity in the grip to hold the detectable metal, in this case 8mm steel bars. After the metal is placed in the grip, the cavity is filled with epoxy and the grip cap is secured on top.
Well there you have it. FP of FOSSCAD has again offered to print and test fire this revolver. I'll report back with the results.
Questions? Suggestions? Let me know in the comments.