For this crazy build we are going to take the ER2 and create a 6 shooter, not because it makes any sense but because it will be a fun challenge.
The first challenge deciding how the cylinder would cycle with each pump. Contrary to most revolvers, particularly paintball, I decided to go with a zig zag cylinder as simpler to design and incorporate in the normal pump stroke (or at least that was the theory).
So the first version of the cylinder was created and printed, the depth was determined by the depth of a single round and the plan was to have a portion of the pump stroke to not engage the cylinder.
This one was sized too small as tests in a prototype body made the pump stroke nearly impossible. This heavy pump stroke was due to the angled "zig" being too shallow. But it was proof of concept, that a zig zag could be printed.
So round 2 was a deeper cylinder which allowed the zig to be less shallow and thus easier to pump/rotate. The length of the new cylinder and its rear stroke is the same length as the full pump stroke.
To go along with the cylinder we need to redesign the bolt. The ER2 bolt is bore drop and thus will not work well with a cylinder "breach." So after copying the profile of the bolt and adding a spring loaded cam to engage the grooves in the cylinder. The design includes a portion which will project into the cylinder at full forward position to both lock the cylinder into position as well as ,theoretically, reducing lost pressure through the rear of the cylinder.
But even with the "lighter" pump stroke it was still horrendously heavy and rough. So this means this will not be a pump build so lets grab some pneumatics out of the parts bin.
With this pneumatics, bolt and cylinder we now need a body to incorporate everything for the cycling of the new front end. To attach the ram and 3 way to the body a bolt and brass threaded ring are captured in the print. At the rear of the body we have holes to attach the valve.
With the addition of pneumatics we have complicated the trigger pull with added need for timing. The nelson valve train gives us an advantage over a cocker valve train in this respect because the auto trigger mechanism means at the end of the bolt travel we can trip the sear without needing any interaction with the trigger itself. So a few iterations of the base plate and we have an adjustable mechanism to trip the sear. Because our prototype body has the 3 way a bit higher than we would like we also add a support bracket for a timing rod and add 2 inserts for bolts to attach our trigger frame.
All assembled we have the current state of the "six shootER2", the frame and asa are also from the parts bin. A timing rod and coupler are printed to get the pneumatics up and running.
Next Steps:
1. Get a pipe adapter fitting to change the 12gram pierce pin to a 1/8th female fitting. This is to keep the valve as stock as possible.
2. Determine how I will run the air to the ASA and Regulator
3. Confirm everything airs up and we can get playable velocity, this may take some testing with springs and potentially an O-ring or two on the breach faces
stretch goals
1. Design and print new cylinder. Current cylinder is good if I want to keep it a 6 shooter, but if I want to add a feed tube to the front/back I will need a "detent" inside the cylinder to prevent double feeding.
2. design a final body to be more astatically pleasing and incorporate a feed tube
Lessons learned so far:
1. Nelson valves are super easy to 3d print bodies for
2. for testing pneumatics a quick disconnect and an airbrush pump works wonders
3. I am not great at eyeballing distances, this lead to the adjustable baseplate.
The first challenge deciding how the cylinder would cycle with each pump. Contrary to most revolvers, particularly paintball, I decided to go with a zig zag cylinder as simpler to design and incorporate in the normal pump stroke (or at least that was the theory).
So the first version of the cylinder was created and printed, the depth was determined by the depth of a single round and the plan was to have a portion of the pump stroke to not engage the cylinder.
This one was sized too small as tests in a prototype body made the pump stroke nearly impossible. This heavy pump stroke was due to the angled "zig" being too shallow. But it was proof of concept, that a zig zag could be printed.
So round 2 was a deeper cylinder which allowed the zig to be less shallow and thus easier to pump/rotate. The length of the new cylinder and its rear stroke is the same length as the full pump stroke.
To go along with the cylinder we need to redesign the bolt. The ER2 bolt is bore drop and thus will not work well with a cylinder "breach." So after copying the profile of the bolt and adding a spring loaded cam to engage the grooves in the cylinder. The design includes a portion which will project into the cylinder at full forward position to both lock the cylinder into position as well as ,theoretically, reducing lost pressure through the rear of the cylinder.
But even with the "lighter" pump stroke it was still horrendously heavy and rough. So this means this will not be a pump build so lets grab some pneumatics out of the parts bin.
With this pneumatics, bolt and cylinder we now need a body to incorporate everything for the cycling of the new front end. To attach the ram and 3 way to the body a bolt and brass threaded ring are captured in the print. At the rear of the body we have holes to attach the valve.
With the addition of pneumatics we have complicated the trigger pull with added need for timing. The nelson valve train gives us an advantage over a cocker valve train in this respect because the auto trigger mechanism means at the end of the bolt travel we can trip the sear without needing any interaction with the trigger itself. So a few iterations of the base plate and we have an adjustable mechanism to trip the sear. Because our prototype body has the 3 way a bit higher than we would like we also add a support bracket for a timing rod and add 2 inserts for bolts to attach our trigger frame.
All assembled we have the current state of the "six shootER2", the frame and asa are also from the parts bin. A timing rod and coupler are printed to get the pneumatics up and running.
Next Steps:
1. Get a pipe adapter fitting to change the 12gram pierce pin to a 1/8th female fitting. This is to keep the valve as stock as possible.
2. Determine how I will run the air to the ASA and Regulator
3. Confirm everything airs up and we can get playable velocity, this may take some testing with springs and potentially an O-ring or two on the breach faces
stretch goals
1. Design and print new cylinder. Current cylinder is good if I want to keep it a 6 shooter, but if I want to add a feed tube to the front/back I will need a "detent" inside the cylinder to prevent double feeding.
2. design a final body to be more astatically pleasing and incorporate a feed tube
Lessons learned so far:
1. Nelson valves are super easy to 3d print bodies for
2. for testing pneumatics a quick disconnect and an airbrush pump works wonders
3. I am not great at eyeballing distances, this lead to the adjustable baseplate.
Comment