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What do you do when replacement furiture becomes too expensive/rare?

12K views 47 replies 9 participants last post by  Mongo 
#1 ·
So there is an effort to make semi auto Stoner 63 guns from cut up parts from Uncle Sam's Chompers. Unfortunately no stocks, handguards or pistol grips survived and those that can be found are becoming increasingly expensive.

Even original parts used by owners of transferable Stoner 63 guns are subject to breakage due to age and the more brittle type of plastic used in the 60s.
So I set out to make reproduction parts for my use and for others. The extruder 3D printers to me have not been accurate nor do they generate a high enough quality of print to use. A colleague found a place that does Selective Laser Sintering of plastic parts. The use a powder and you can upload your model and get an instant quote.
So I started off reverse engineering the pistol grip of the Stoner 63. This took 3 generations since it was the first time dealing with the process.

Here is the 3 generations pictured. They are printed in nylon 12 and typically are white but you can have them dyed to the color you desire.
I am very please with the results. The first generation you can see the carving I had to do on it to get it to fit. I hit this thing with a 3 pound sledge and did not hurt it. The dye job has slightly faded as I left on my desk in direct sunlight for several months to see what would happen. They can be re-dyed if you desire or painted.

From left to right: Final pistol grip with trap door, Final pistol grip w/o trap door, second generation in the white to verify the required changes to generation 1 which is the one to the far right.




Closer picture of the trap door version


The model for the trap door pistol grip

 
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#2 ·
So the "window" butt stock is the most sought after stock for the stoner 63. If you can find an original they will go well over $1K for one. The window in the stock is used as the take down tool for the Stoner 63 bolt group and is not a sling mount point. This was my next item to try and duplicate. I actually own an original as well as a reproduction one that is made of solid thermoset plastic. Now the stocks have more parts, that include a metal shoe at the mounting point int he front, a butt pad, and the bar in the "window" as well as the blind spline nut located in the stock.

I started by making a soliworks model of each component.




As you can see I had to make a method to make the bar in the window captive so I designed a glue in piece that captures the bar in place. The print of the stock came out great and here it is next to the original. The original is smooth where as the exterior of the printed on is more of a modern flat finish. I believe you could wet sand the printed stock to mimic the original if desired. The butt pad was printed in the same material as the stock since printing it in rubber is 3X the price and is done via a different method. Other options are being explored for the butt pad currently.


Showing the socket where the plug goes to retain the bar in the window.

Plug in place holding the bar in place. The 3D print is so accurate it would stay in place even without glue though I intend to glue it to make sure.

Stoner 63A in rifle configuration with the 3D printed stock mounted.
 
#3 ·
NWM/Mauser obtained the rights to produce the Stoner 63A in Europe. They created some unique items for the Stoner that are extremely rare in the USA. One of them was a stock that I liked the look of and wanted to give it a try to copy.


The stock had less parts than the windowed one but I only had the picture to design from. Here is the model I came up for it. It uses the same butt pad as the rest of the Stoner stocks as well as the same shoe metal. Otherwise its hollow inside.


Once again the stock printed great. Since there is not a window in the stock the stock tends to be a little to squishy in the middle but the plan for all the stocks is to use spray in foam to deaden the sound and give it a bit more rigidity. I have since changed the model for this one to include a reinforcing ribs inside.Picture of both 3D printed stocks.
Stock mounted on the Stoner 63A in rifle configuration.
 
#4 ·
The butt pads are the part I'm still working on.

Here is the picture of them in different positions. The butt pad on the far right in the pictures is a reproduction one done in a rubber like substance by an unknown maker. It is thicker looking than the 3D printed ones since there were two different thickness ones used in the Stoner 63 stocks.

As you can see, I miss counted the number of horizontal nubs on the original when i made my model. The test is a bit off as well and is too thin to be effectively 3D printed. I have corrected the deficiencies in my model and the next generation will be correct.

As for printing the next generation, I'm working on that with a different print place for a test as well as possibly pulling a mold of the 3D printed pad and molding them myself.



 
#5 ·
The last part I have had 3D printed is the handguard. These are also rare and expensive when found. The 3d Print once again came out very nice and is strong.

Solidworks model.



The 3D print compared to the original. As you can see there is some rivets and metal that need to be sourced to finish these off.



 
#8 ·
the answers




I will be selling them sans the metal after I am finished with the set.

I have been playing with this stuff a bit too. How much are the prints costing you when doing a single prototype? I too have found that 3D printing was not giving me the results I needed.
The one stock piece is less than $100
 
#9 ·
...necessity..

...'is the mother of invention...' Well done...!! If not for folks who try to make better stuff for less cost,there would not be many 'hobbies' we could afford. A classic gun like the Stoner 63 deserves such attention....wish I could afford one...
 
#11 ·
My next little project fun. 3d printing is addictive as hell

The original drums for the Stoner 63a are now in the 10K range and they are thin aluminum so I don't take the drum out to the range to shoot it much since a simple drop of the gun could cost me a lot of money, specially since my drum is NOS. So I decided to design one that is inspired by KAC recent LMG one for my Stoner 63A.

I am test printing the mount first for fit up checking before I print eh entire unit but here is what the design will come out as.





 
#14 ·
Here is the second redesign of the Stoner 63 ammo box. The first had issues due to a blown dimension on an assumption I made that was not correct. This one is designed to be restrained by the rear handguard mounting point and the magazine latch in the trigger group. It also uses the bottom of the receiver as a stop. The problem as you can see in the little crappy movie I made, show that the latch does not restrain side to side motion. I am debating how to design a restraint into the rear area. The mount does auto eject like I wanted when the latch is pressed. I am thinking about having the mount use the heads of the rear handguard take down screw as a mounting point so it gives a larger side to side load bearing area. The rear restraint method is an issue since I have to figure out which areas have a manufacturing tolerance and work with interfacing with them.




 
#19 ·
Here is some quick and dirty shots of the ammo box. I'll get better ones on the gun when there is better light here. You can see the white area on the rear is where I had to trim a little to get the catch to fit. The box is very strong, it does not deflect much even with heavy pressure from my hand. The text came out very nicely as well as the load indicators. I am thinking a few changes and it will be ready to use/sell.







 
#24 ·
Here is the next generation of my Stoner ammo box experiment. As you can see I have changed the latch positions and lowered the box a bit as well as enlarging it slightly so its easier to load. I added stiffening ribs on the top and bottom. The later pictures show the first generation box next to the latest.









 
#33 ·
Well here is the latest on the 3D repro prints. The rifle/carbine handguard and slotted LMG handguards came out great and are shown with the previous LMG/auto rifle handguard. I also printed the standard stock and as you can see I added a rib in the middle that makes the stock much stiffer and it does not make sound like an instrument when you tap it. The new butt pad is also shown and the lettering is now fully formed as well as the correct number of ribs on the butt pad.








 
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