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Let’s us 3D print a gun – Part 4- It’s alive!

Fun stuff first.

I took the 3D printed lower to the range and tested it out. Ran fine.

When I first was thinking about doing this project, I expected to 3D print a gun, then shoot it until it broke. After I printed the Gluty lower, I realized if I tried to do that I would end up shooting all my ammo, that would be kinda hard to replace right now.

I fired 190 rounds, I stopped because the handguards got very hot. I did have a couple of minor issues. The first mag I tried was a Lancer mag (I think they have a new generation, if so, this is a first gen mag). I over inserted it and had a hard time removing it from the gun. So I didn’t use the Lancer mags, and instead used a USGI mag and four Magpul 40 round mags. One of the Pmags did not have the follower come up completely causing the bolt to fail to lock to the rear upon firing the last shot. I would call this a mag problem, not a gun problem. I’ve previously reported about having these issues with my Magpul 40 round Pmags.

I have no doubt, that with quality magazines, I wouldn’t have had a single issue.


Now let us back track.

I was printing the Gluty 9mm pistol. It would use a Glock barrel and mags, and the bulk of the chassis would be printed. While the bolt is in a printed shell, it is mainly a big hunk of steel rod with a notch cut out of it and holes drilled though it. The work can be done with a Dremel and drill press, but most of my tools are packed away in my horder’s nest, so I decided to pivot to a simpler project. An AR15 lower.

There are a number of good options. I had a hard time picking which one to print, finally picked the “Aliamano Phobos AR-15 lower”, made by ArmaDelite, which is “based on the JT-Vangard and Phobos models”.

This one was picked because it looked like it would be easier to print than some of the other options. I don’t know if that is truly the case, but it is why I picked it.

I was able to print it in a single piece, out of PLA+ filament.

Online, you can find many a person who says that ABS would be the better choice for printing a firearm. But when you read reports of people who are printing firearms using FDM printers like mine, they talk about ABS been weak along the layers and needed acetone or MEK welding, or other reinforcements. I’ve never worked with ABS in printing, so I decided to try PLA. That is also what I had on hand and I wasn’t about to spend money on this project.

I don’t so much printing with supports, so I tried settings the support material to be printed at a 45 degree angle to the main part. I hoped that would make it easier to remove. That was a mistake. Instead of peeling off in large chunks, the support material came off in very small pieces and I spent about 8 hours taking this print from the state it was off the printer, into being an assembled lower.

Pretty much all the holes had to be drilled out to size. With the exception of the firing pin holes, those came out perfectly in spec.

After 6 hours of scraping and peeling away support material bit by bit, the lower was still covered with it.

The worst part ending up being the threading where the receiver extension (buffer tube) goes. Some of the support material at the top would not come out at all. I finally had to take a sanding drum for the Dremel, melt away much of the plastic, and use a receiver extension to tap all those threads. That was miserable work, and I was afraid I was going to scrap the lower. I even got ready to print another one with different settings right before I finally got the receiver extension to screw in all the way.

I ran into a few other problems as well. The slot for the magazine catch printed undersize and I had to spend a while with a file to clean it out. Then I found the cheap old parts I had laying around were screw up.

I don’t know what brand that is, but it is a plastic mag release catch button I pulled out of an old AR15. It screws onto the match catch crooked.

So the mag release on this gun binds slightly. It works, but not as smoothly as it should. I could spent more time filing away plastic to account for this out of spec button and the tight slot in the lower, but it works. I’m not looking for perfection here, just functionality. “Anything worth doing, is worth doing poorly.”

The other issue I ran into was that when I went to tap the grip screw hole in the receiver, the tap I used just ripped the plastic out of that hole. Reaming it out over sized. I started to try a couple different solutions, finally decided to go an easy route and printed up an AR15 grip and glued it to the lower. I left out the spring and detent for the safety and I didn’t want to permanently leave them in this lower, and the safety is already quite stiff as it is.

A crummy fix, but it works, and that is the goal here.


Aliamano Phobos AR-15 lower

If I were to complain about this lower, I would have two main gripes. It is not compatible with an upper that has a forward assist, and the trigger guard is a little thin for something 3D printed, and I believe it would break under abuse. I feel like I could break it by hand. It wouldn’t stop the lower from functioning, but it could be much beefier.

A smaller issue is that the reinforcement make it a little harder to access the safety. I was able to quickly access the safety for rapid shooting drills, but it is no where near as easy as on a standard lower.

The massive reinforcement where the receiver extension screws into makes installing the receiver extension a major pain. I placed the receiver extension in a vise and use a wrench on the lower to turn it. Took a lot of effort. I was worried the lower would break. Turned out fine.

But the receiver is really wide in the back. You will want to use a larger, satellite dish sized, charging handle latch. I read that other people who have printed AR lowers tend to be fond of using side charging handles on them

“That just sounds like an AK with extra steps.”


This lower has a very cut away magwell. Over the years I have seen several ARs with cut away magwells and they have all functioned fine. This one is even more cut away. Inserting a magazine I found I could move it a fair bit side to side or tilt it forwards and backwards. So when shooting the gun, I tried tilting the mag back, forwards, left, right, and to the extreme diagonals, but I was unable to induce a malfunction during rapid fire.


I have no doubt this lower could withstand short term heavy use. But PLA degrades with time. Some like to push that PLA is better for the environment because it is biodegradable. Time, humidity, and high temperatures will all make PLA degrade faster. But it still is a plastic, and it won’t completely biodegrade any time soon under normal conditions.

I looked into the longevity of PLA printed parts, and I couldn’t find any hard numbers. I do know that stuff I have printed in PLA seems to get more brittle over time. So I am going to stash this lower away for a while and see how to holds up a few months from now.

It is likely that a PLA lower would hold up for several years.

Still for the time and effort involved, I think 3D printing firearms is more an exercise in novelty than a practical production. It does help show the futility of anti-gun laws.

Let’s 3D print a gun, Part 3

So you got a 3D Printer, and you went online and downloaded a 3D model of a gun. You upload it to the printer and hit print and a few hours later you have a gun, right?

No, there are a few more steps.

When you get a 3D printer, even if it is assembled, it needs to be calibrated. At a minimum the print surface (the bed) needs to be leveled to the print head.

The printer needs to be set to extrude the correct amount of material at a time, and the accuracy and precision can be adjusted.

I usually use my 3D printer to make decorate objects or toys, which are not precision parts. So I didn’t worry about much about those tweaks on my Tevo Tornado. Back when I had a Tevo Tarantula I spent countless time trying to improve performance and never really got it where I wanted it.

PLA filament goes bad when exposed to humidity. I live in Florida. You might realize what the problem is. While spools of filament are vacuum sealed, once opened they have a limited useful life span.

Various brands of printer filament may use different formulas, so you will likely need different print settings for different brands of filament. Even worse, you might need different settings for different color filament.

Running the printer at different temperatures also drastically affects the print quality. Ideally, when ever you switch filaments you would print a “temperature tower” which is a single print that is done at various temperatures so you can see what temperature provided the best qualities, usually focusing on layer adhesion.


Ugh, that is a whole lotta work. Screw it, I’m gonna skip all those steps.


One more important/boring bit of how 3D Printers work:

People use 3D modeling or Computer Aided Drafting & Design software to make 3D models of parts. Popular options for mechanical design include Solidworks, SolidEdge, Alibre, Fusion360, ProE, Creo, etc.

This software is used to make a 3D model which is then usually saved/exported into the .STL format, which is most commonly used in 3D printing.

A STL file has the data of what the model is, but omit details like scale or tolerances.

Then we have “Slicer” software. In CNC machining, we tell a machine to move along the various axis and make cuts, drill holes, etc. The code to do this is called “G Code”. Simple programs can be written by hand, more complex projects may use Computer Aided Machining (CAM) software to generate the G Code necessary to machine the part.

Slicer software takes that 3D model from the STL file and slices it into thin horizontal slices, then generates G Code to tell the 3D printer what movements it needs to make to print out that part.

When I ran a FADAL CNC Mill, our programs often had a few hundred lines of G Code. When I run my 3D printer, a print might require a few hundred thousand lines of G Code. No one would be writing a program like that by hand.


A render of the 3D printable “Liberator” pistol design.

I had initially planned to print a single shot .22 that would be mostly plastic. Figured it might survive a round or two.

Hopefully.

BUT, and a bit one at that, there is this law on the books about “untraceable firearms”.

The United States Undetectable Firearms Act of 1988 (18 U.S.C. § 922(p)) makes it illegal to manufacture, import, sell, ship, deliver, possess, transfer, or receive any firearm that is not as detectable by walk-through metal detection as a security exemplar containing 3.7 oz (105 g) of steel, or any firearm with major components that do not generate an accurate image before standard airport imaging technology.[1]

https://en.wikipedia.org/wiki/Undetectable_Firearms_Act

This law, like most of our stupid laws, came about because of stupid reasons. Idiots out there thought that these new and ultra evil Glock pistols could slip right though metal detectors.

Thus, while we COULD print an almost entirely plastic pistol, it would be illegal.


I’ve learned that some people have modified the “Liberator” design to accept a steel block epoxied (permanently) into the frame.

When I started this project I intended to print the “Gluty V0.2A” 9mm pistol. It is similar to a 9mm AR15, but uses a heavily reinforced printer upper and a Glock barrel.

The “Shuty” was the first 3D printed firearm I found interesting.

Picture of the Shuty pistol, found online.

The Shuty was designed somewhat like a 9mm AR15, but used a 3d printed mag and a Glock barrel. The Gluty was an upgraded Shuty that used Glock magazines.

There is a newer version of the design called the “FCG-9” which is designed to use as many 3D printed parts as possible so that people who do not have firearm parts available to them could build it. It still uses an AR15 fire control group, but it no longer uses a Glock barrel.

FCG-9 Picture from the internet.

I hadn’t used my 3D printer in some months. The better part of a year it just sat around getting dusty. I had a new sealed package of cheap PLA+ filament. So I decided I would throw that in the printer, dust off the print bed (I use an Ikea mirror for a smooth flat surface), and start printing.

Smart thing would have been to calibrate and tweak the printer for the filament. But what fun would that have been.

The Gluty lower took about 27 hours to print, if I recall correctly. As I said in a previous post, 3D printing can not print a cantilevered structure. If you would to try and print a T shaped object, the top of the T would collapse during the print and it would fail. So you would either print the T shaped object upside down, or use supporting material to provide a scaffolding to the part.

There are many different ways to set up the support material. As I have previously done very little printing with support material, I used the default settings. This was probably a mistake.

Hours and hours later of using a scraper, plyers, side cutters, I was left with lots of support material still in the lower.

While working on the lower, I went ahead and printed the upper.

It came off the printer looking like this:

I spent many more hours removing support material.

Finally, it was starting to look like something that might actually work.

So I went and read the instructions on how to make the Gluty pistol.

Turns out it requires a little more metalworking than I am set up to do in my little hovel of a home.


I could have continued with the Gluty project, but I was starting to run low on filament, and the monitor on my laptop (Surface Pro 2017), which I use to run my 3D printer, started to fail. I decided it was time to shelve this project and go in a different route.

I looked at a variety of AR15 lower designs that are printable. Picked one that seemed decent to me and printed it out. Since then, I have assembled it, and am about to take it to the range for test firing. We will go over that next time. I’ll also go into more detail about the Gluty design.

Let’s 3D Print a gun Part 2

Alright, where do I start?

I’m a Machinist. I’ve read several times that Machining is the slowest and most expensive way to manufacture a part. In my opinion, hand tools are slower, but I suppose that is beside the point.

3D Printing is a new, “additive”, manufacturing process that can be very cheap. But, it is very slow. Much slower than cutting a part out of a block of material.

There are a number of different types of 3D Printers. Some use vats of resin, other lasers to sinter together materials, and many other designs, but usually when people talk about 3D printing they are talking about FDM printers. A “Fused Deposition Modeling” printer lays down layer upon layer of melted plastic to build up the part.

Your average over the counter 3D printer feeds from a spool of plastic that looks like weed eater trimmer cable. It is a robot controlled hot glue gun. There are a large number of various plastics that can be printed by these types of printers including, ABS, PLA, PVS, Nylon, etc. PLA plastic is the most popular, but some people use ABS for increased strength, or PETG for food safe items, TPU for flexible parts, etc. The various plastics have different benefits and downsides.

FDM printing can be cheap, fast (compared to other forms of 3D Printing), and the wide variety of materials allow you to pick one best suited for what you are doing. But FDM printing tends to be less precise than other forms of printing or manufacturing. Printing parts in layers leave the potential for delamination and makes the parts less durable when under tension. These layer lines prevent smooth vertical surfaces and may require additional work (sanding, smoothing, filler, etc) to creature a smooth finish, when a smooth finish is required.

One of the best things about 3D printing is that you can produce complicated geometry that would be very hard or impossible to make other ways, and you can print parts like springs, hinges, gears, and similar movable components as part of a single print. An early example was printing a adjustable wrench in a single print.

Blah blah blah. You can find the history, and minutia, and more details on 3D printing all over the place online.


I get asked, “What 3D printer should I buy?”
First you should ask your self if you really should be buying one?

There seems to be this impression that 3D printing is push a button and get a part. If everything is set up well it is not too far away from that. But lots of work has to be done to get there. Unless you only plan to print up stuff that other people have already designed, or you have your own 3D modeling experience and plan to design your own parts for 3D printing, it is probably not worth getting a printer.

Now if you only planned on printing stuff you found on thingiverse or already know how to do 3D modeling, then it might be worth getting a 3D Printer.

Personally, I tell people to buy a Prusa brand printer. Sure they 3-4 times the cost of many other perfectly good printers, but they are far easier to get running well and have far better support and a community to help you. Every time I run into problems with my printer I kinda regret I didn’t buy a Prusa i3. That said, the size the various Prusa printers can print is much smaller than my Tevo Tornado, so I do like having the larger print capability.


So what were we talking about again? Oh yea, Ghost Guns.

YOU WOULDN’T DOWNLOAD A GUN

Fuck you, I would if I could.

If we were going to make a gun from scratch found at the hardware store, a single shot would be the easiest and fastest to make.

Something that functioned like a bang-stick or a pop-gun could be made rather fast.

I learned about this kit last year, HERE. Single shot firearms are the easiest to make.

After that, an open bolt submachine gun is the easiest to make. Weird how that is. It is easier to make a full automatic only gun than a semi-automatic.

The “Improvised Special Purpose SMG” is suppose to be makeable in 2 hours with 20 dollars worth of supplies.

Open bolt guns can have a fixed firing pin and all the fire control mechanism has to to is release or hold the bolt. Semi-guns are a little more complex.


Humpth, I appear to have wandered off topic.

It is perfectly legal to build your own firearms. What could be more American than making your own guns?

There are some limits to what you can legally build. I’m no lawyer and I can not provide you with legal advise on the matter.

Generally, you can build your own gun for your own use with out a serial number or makers markings. The proverbial “Ghost Gun”.

A home built Glock 19 style gun with no serial number.

Big media would have you believe that terrorists and felons are clamoring to make untraceable firearms in their homes. In reality, these guns tend to cost more than a standard firearm, and have plenty of a paper trail. Unless you bought kit somewhere for cash, it can be traced back to you.

IMHO, it makes more sense cost, time, and reliability wise to just pick up a used gun locally for cash in a face to face sale.

But hey, this isn’t about what makes sense, this is about making our own guns.

Cause we are Americans, and we do what we want.

To be continued.