Updates Part 2: gun modeling (mostly) complete!
As mentioned in my previous post, the modeling of the gun is mostly complete after a lot of spread-out time nailing everything down. Some of this design may change a bit, but in general it’s mostly set. Additionally, the part I’m most proud of: all of the parts are designed to be easily 3D printable: minimal overhangs/support material required, all easily attachable, and they mesh with each other relatively well. The main thing that I’ve learned through this process is that wow, heat-set threaded inserts are your friend. They add so much more flexibility in how you can put things together, letting you add threads almost anywhere so you don’t have to have screws going through a surface, only too it. Technically on McMaster-Carr, they’re called “Brass Flanged Screw-to-Expand Threaded Inserts”, but at my local hardware store the exact same ones are called heat-set inserts. They look like this (albeit actually brass colored):
Basically, to use them, 3D print a hole slightly smaller than the insert. Then put this against the hole, and hold a soldering iron to it at a pretty high temperature (but not obscenely high, then it’ll start deforming the rest of the plastic around it). After a bit of pressure and time, the insert will begin to melt its way into the hole, and once cooled the plastic will set around it and make a very solid attachment point. Additionally, since they are technically "screw-to-expand”, it makes it even more solid because once you screw it in there’s more pressure.
Anyways, on to the gun!
Fully assembled gun
Well, first, a disclaimer: the color of these parts is by no means representative of how we'll paint it finally in real life: I just made them kiiinda close just for visualization purposes like this.
Now, there are a couple immediately missing things from these pictures. First, there’s no laser! I’ve yet to determine a lot of the more electronic parts of the gun, I was more set on the physical form of it, so I’m going to get to that part later. Second, there’s going to be a yellow tube running across the top of the gun, I just haven’t gotten around to adding it yet: that’ll probably be some sort of plastic tubing bent with a heat gun. Aside from that, however, most of the physical body of the gun is designed and theoretically ready to assemble. I’m currently, in a separate file, assembling it from scratch and writing down steps to ensure that it’s actually humanly possible to assemble (as I’ve discovered in my robotics years that “it works in CAD” doesn’t always mean “we can put it together in real life”, mainly because you can’t always reach nuts and bolts where you need them).
Gun back
The back of the gun is where 75% of my time was spent, because it has the most (read: only) moving parts of the gun, and is also the most intricate. The main “body” of the back consists of 5 printed parts, and laser cut wood or plastic for the handle and trigger.
Now, if there’s anything I’m really not happy with here and that I will mostly likely change again, it’s the cell locking arm. The first issue I encountered is that, in the game, there’s only one arm holding the cell in. This, at least in the current iteration, wouldn’t work well and the cell would probably just fall out if you flipped the gun upside down (and it would be loose even if you didn’t). So I added a second prong holding it in vertically as well, but this quite frankly looks horrible (in my opinion):
I am considering adding an inset in one end to fit the terminal of the cell, locking it a bit better, but we’ll see if this works as intended. Might even add a spring, making it funnily similar to current AA battery holders.
Moving on from this, I did do at least some future electronic planning, but only because it actually affected how the trigger moved as well: there’s a trigger switch inside the gun.
You can see here that the trigger has a little arm sticking through to the inside of the gun. When pushed to a certain point, it will encounter the spring-loaded arm of the micro switch, which both will serve to fire the gun and to provide some minimal recoil against the trigger.
Additionally, we also incorporated the dial from the back of the gun. For now, it’s simply just cosmetic, but we may eventually make it be a functioning dial and use it to adjust laser strength (or something else).
Gun barrel and front
The gun barrel actually is going to be vinyl fence post, which was a wonderful suggestion from the people over at Arts & Crafts Stack Exchange (https://crafts.stackexchange.com/questions/5559/mostly-off-the-shelf-or-at-least-quite-easily-fabricated-rounded-square-tubing/5561#5561). It’ll be mounted by 8 very long screws to an also very thick 3D printed block coming off the back of the gun. This will hopefully be enough to keep it mounted well, although I wouldn’t trust it for large amounts of force.
The barrel of the gun also has a grip on the bottom, which is where the user’s left hand will go (although I guess technically this is ambidextrous, so it’s just their off hand, whichever that is).
Moving to the very front of the gun, we have a multi-layered part (which as I wrote this I just realized wasn’t properly attached, so hey, who says blogging is pointless?). As mentioned earlier, I don’t have a laser in there yet, but I will at some point, or at the very least a red LED or two.
Underneath this part, we have a rod running along the length of the gun. This is a threaded rod with a few embellishments, and then the main part of the rod is covered in a plastic tube for cosmetics. This way we have a structural piece holding the length down, but it also looks good. It runs back and connects to the handle.
I could go on for hours about some of the specific parts of this gun, but to be honest, I don’t think anyone here is really that interested (although hey, if you are really interested in how I made this manufacturable and assemblable, hit me up and I’d gladly talk into your ears for hours). I’ll keep posting updates here as I make more progress. Now that band is winding down and break is approaching, I should be able to start really making headway, and I’ll keep everyone here updated as I do.
Thanks if you somehow read this far down, and keep an eye out for more progress!
