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Stacy: Mag Fed Pistol F.A.R. - First Homemade, Advice Appreciated

homemade magazine pistol

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#1 TulipMama

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Posted 13 October 2016 - 01:12 PM

Hello,

 

This will be my first post on Nerf Haven, though I have been wandering around on here for the last couple weeks, so please be gentle with me.

 

I have been trying to design a nerf blaster with the following requirements in mind:

 

Compatible with standard purchased Nerf Magazine/darts

Easy to build ie, dremel and hand tools only

Low Cost

Mechanism easily modded between pistol/rifle/shotgun

 

With these thoughts in mind, I did my research and managed to come up with the following:

 

stacy_operation_by_the_tulip_mama-dakz51

 

stacy_exploded_by_the_tulip_mama-dakz519

 

The bolt (highlighted in green) is pulled back by a pair of screws that are slotted in the 1 1/4" pvc body. I'm using an F.A.R. trigger system that catches on a 1/2" washer built into the end of the plunger.

 

The bolt has to be pushed forward to seat the nerf dart in the barrel, and right now this end of the bolt is a simple tube (up-cycling the body of a bic pen) but I think I'll try and find a way to put in a hollowed out 5/8" dowel to push the dart and make a seal on the barrel.

 

When the trigger is pulled, the plunger is sent forward and the air is forced through the tube and up the back end of the dart. The next dart moves up into the chamber when the bolt is pulled back again.

 

 

I'm hoping to get some advice from people more experienced in making nerf blasters. The first design I tried to make failed horribly in part because I attempted to make something I didn't have the tools for, and partially because of assumptions I made in my design. With this, I'm hoping some noble members will be able to point out some design changes that can help that I haven't seen.

 

Thank you in advance,

 

Sincerely;

 

Tulip Mama


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#2 Meaker VI

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Posted 13 October 2016 - 03:54 PM

Welcome to the Haven!

 

The FAR is a pretty antiquated design, I'd recommend looking at more modern blasters (specifically the Caliburn that Slug just finished) for ideas.

 

However, here are some comments on this design:

 

1) You're using lots of dowels. Wood, plastic, or other? Before you head to the store, know that none of the pipes you'll be using are anything like the nominal dimensions they use as names. 1" Is something like 1.315" OD and ~1.05" ID. So your dowels will need to be lathed to exact fit if you want them to seal.

 

2) Your plunger is an odd design.You'll be on your own testing it, and if it's solid it'll be really heavy compared to more standard designs. IIRC, 1/2" PVC with a 1/2" PVC fitting on the end is what Boltsniper used to nest inside the 1" Plunger tube.

 

3) 1/2" PEX should work as a bolt-front/dart-pusher. It is 1/2" OD and has a hole in it already.

 

4) For simplicity being a design goal, you have a surprising amount of complicated-to-machine parts. Most builders have moved away from cutting slots in PVC as much as possible because doing it accurately without specialized setups is a pain in the neck.


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#3 TulipMama

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Posted 13 October 2016 - 04:19 PM

Welcome to the Haven!

 

The FAR is a pretty antiquated design, I'd recommend looking at more modern blasters (specifically the Caliburn that Slug just finished) for ideas.

 

However, here are some comments on this design:

 

1) You're using lots of dowels. Wood, plastic, or other? Before you head to the store, know that none of the pipes you'll be using are anything like the nominal dimensions they use as names. 1" Is something like 1.315" OD and ~1.05" ID. So your dowels will need to be lathed to exact fit if you want them to seal.

 

2) Your plunger is an odd design.You'll be on your own testing it, and if it's solid it'll be really heavy compared to more standard designs. IIRC, 1/2" PVC with a 1/2" PVC fitting on the end is what Boltsniper used to nest inside the 1" Plunger tube.

 

3) 1/2" PEX should work as a bolt-front/dart-pusher. It is 1/2" OD and has a hole in it already.

 

4) For simplicity being a design goal, you have a surprising amount of complicated-to-machine parts. Most builders have moved away from cutting slots in PVC as much as possible because doing it accurately without specialized setups is a pain in the neck.

 

I didn't realize that the F.A.R. was antiquated, it was the only bolt action, mag fed system I could find that I could adapt to my liking. I would have much preferred to use a Rainbow style catch, but couldn't reconcile the designs.

 

Also, I don't know how Slugs' Caliburn works, I can't tell from the pictures how the catch/trigger mechanism works, and while I can guess at most of the other features I can't be certain. Do you know if he plans on posting a more detailed explanation?

 

1 & 2) I realize the OD/ID differences of PVC and dowels, I have a little chart on my desk for me to reference when I'm trying to figure out what fits where. I have also thought of using a 1/2" cap, but it requires a fair bit of sanding to actually fit in a 1" PVC pipe, and the 1" dowel fits rather nicely, and I intend on fitting the dowel with O-rings to make up the slack in the seal. I see a lot of plungers with a sort of... suction cup looking thing on the end though, could you tell me what that is? I'll keep this in mind though, I hadn't really considered the final weight of the assembly and this could be a quick way to lighten the load. 

 

3) That's very helpful, I'll definitely keep that in mind. 

 

4) I have pretty steady hands, I've managed to make decent slots in my failed attempt, though I do agree it is a pain. I just don't know how else to access the plunger without a rear-pull plunger, which I can't really use because of the bolt.


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#4 Meaker VI

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Posted 13 October 2016 - 04:50 PM

I didn't realize that the F.A.R. was antiquated, it was the only bolt action, mag fed system I could find that I could adapt to my liking. I would have much preferred to use a Rainbow style catch, but couldn't reconcile the designs.
 
Also, I don't know how Slugs' Caliburn works, I can't tell from the pictures how the catch/trigger mechanism works, and while I can guess at most of the other features I can't be certain. Do you know if he plans on posting a more detailed explanation?

 
It's basically a rainbow catch blaster with a magwell on the front and a breech that pushes the plunger back. The breech is essentially a second plunger attached to the pump arms with a dart-sized tube on the front.
 

1 & 2) I realize the OD/ID differences of PVC and dowels, I have a little chart on my desk for me to reference when I'm trying to figure out what fits where. I have also thought of using a 1/2" cap, but it requires a fair bit of sanding to actually fit in a 1" PVC pipe, and the 1" dowel fits rather nicely, and I intend on fitting the dowel with O-rings to make up the slack in the seal. I see a lot of plungers with a sort of... suction cup looking thing on the end though, could you tell me what that is? I'll keep this in mind though, I hadn't really considered the final weight of the assembly and this could be a quick way to lighten the load.

 
You know what, I was thinking 200 PSI 1" PVC ("Thinwall"). That's what Boltsniper used. It's sometimes hard to find, but if you ask stores that carry PVC usually have it somewhere.
 
Suction cup is a skirt seal or some variation. It isn't mandatory, it's just an efficient plunger head seal. I ususally use superlative heads (neoprene washers sandwhiched between fender washers) or dash-216 orings (for 1-1/4" sch. 40 PVC plunger tubes).


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#5 CaptainSlug

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Posted 13 October 2016 - 08:12 PM

The 3/16" tubing is too restrictive based on my experience in trying to do something similar. And you don't seem to have anything that seals that small tubing inside the barrel. As such when the plunger fires the darts will be pushed a very small distance before the rest of the pressure is allowed to just vent into the mag well.


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#6 Draconis

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Posted 13 October 2016 - 11:09 PM

3) 1/2" PEX should work as a bolt-front/dart-pusher. It is 1/2" OD and has a hole in it already.


Small thing, but I want to avoid confusion. 3/8" PEX has a 0.5" OD. 1/2" PEX has a 0.625" OD.
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#7 Montymarks

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Posted 14 October 2016 - 11:14 AM

This looks a lot like a retaliator with a mucho grande plunger tube.
Also, that looks pretty nice intro to homemades, but that would proly need them xpensive tools to make it. There are much easier pistols that might not be mag fed, but are simpler to make, cost less, and could possibly run a small hoppidy hoppery doop.

Note: I am decently good at this hobby, I just talk like a retarded toddler.

Eye b0ss

-Montymarks

Edit: You should make it use artifact darts or stephans.

Edit 2: Nevermind, i'm just extra hyper today.

Edit 3: No, just as retarded as usual...

Edit 4: I've used the word retarded in this post more than some youtubers (cough cough, all I needs ta say) in all their videos.

Edited by Montymarks, 17 October 2016 - 07:31 PM.

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#8 TulipMama

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Posted 14 October 2016 - 12:49 PM

The 3/16" tubing is too restrictive based on my experience in trying to do something similar. And you don't seem to have anything that seals that small tubing inside the barrel. As such when the plunger fires the darts will be pushed a very small distance before the rest of the pressure is allowed to just vent into the mag well.

 

Ya, I thought that without a positive seal, most of the pressure would be lost, that's why I mentioned I may be going with a hollowed out piece of 5/8" dowel as a bolt (something I was trying to avoid for a few reasons). I've looked into the PEX that I can get locally, and while the charts I've looked at confirm what Draconis says below, when I call the hardware stores around me, all of their 1/2" PEX has a 0.5+ OD, and nobody has '5/8" PEX' which I could assume would have the 0.625" OD that I would have liked to use as a bolt/breach. I've looked into similar sizes of brass/copper pipe, but it would be hard to manufacture my parts and much, much more expensive than I want. 

 

EDIT: I should have said that nobody has a reasonable length of 5/8" PEX. I don't want to spend $130-300 on a roll of something I need 7 inches of.

 

Does anybody have an idea what I can use to make a bolt/breach without PEX? Keep in mind, I only have a dremel and hand tools, no drill press or lathe.

 

Small thing, but I want to avoid confusion. 3/8" PEX has a 0.5" OD. 1/2" PEX has a 0.625" OD.

 

 

This looks a lot like a retaliator with a mucho grande plunger tube.
Also, that looks pretty nice intro to homemades, but that would proly need them xpensive tools to make it. There are much easier pistols that might not be mag fed, but are simpler to make, cost less, and could possibly run a small hoppidy hoppery doop.

Note: I am decently good at this hobby, I just talk like a retarded toddler.

Eye b0ss

-Montymarks

Edit: You should make it use artifact darts or stephans.

Edit 2: Nevermind, i'm just extra hyper today.

 

Unfortunately for me, I'm making this nerf gun for somebody who has a particular aesthetic, and a mag is definitely a requirement. In addition, I have to stick with the standard nerf darts as well because of the field that my friend will be playing on, custom or homemade darts don't fly. Because of that, I also can't use a hopper, though, again, they don't fit my friends aesthetic. 


Edited by TulipMama, 14 October 2016 - 01:33 PM.

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#9 Draconis

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Posted 14 October 2016 - 02:35 PM

This is what I was trying to avoid.  It is called /1/2" PEX/ because the nominal inside diameter is around 1/2", but the outside diameter is 5/8".  If you are looking for 1/2" OD, you want the 3/8" PEX.  It is available at Home Depot and Lowe's for about $4 for five feet.


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#10 TulipMama

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Posted 14 October 2016 - 02:50 PM

This is what I was trying to avoid.  It is called /1/2" PEX/ because the nominal inside diameter is around 1/2", but the outside diameter is 5/8".  If you are looking for 1/2" OD, you want the 3/8" PEX.  It is available at Home Depot and Lowe's for about $4 for five feet.

 

I understand that. Home depot has a product they call 1/2" Pex, but it is the OD that is 0.5" (I called and one of the associates was kind enough to measure it for me) and I am looking for a product with a 5/8" OD, which they don't seem to have in lengths that I would consider reasonable.

 

EDIT: I took a boo at Lowe's, which for some silly reason didn't show up in my earlier searches for PEX, and the dimensions for the 1/2" PEX do seem to fit, thanks!

 

I've changed the design some to incorporate a 1/2" PEX bolt, and I've also managed to shave off about 3/4" from the end of the blaster.

 

stacy_operation_2_by_the_tulip_mama-dal3

 

The step in the PEX seals up against the barrel (I'll probably throw in some silicone rubber to seal better after testing). The PEX is held in by seating it in a 1/2" pvc pipe, which is seated in a 3/4" pvc pipe before finally seating in the 1" pvc pipe. Liberal dollops of hot glue or silicone rubber and an unfortunate amount of sanding will yield the sealed face I'm looking for, hopefully. The little hole is for a #4 bolt to act as my cocking handle which will ride the slots in the 1 1/4" body.

 

Any further thoughts or suggestions?


Edited by TulipMama, 14 October 2016 - 04:08 PM.

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#11 Meaker VI

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Posted 14 October 2016 - 06:43 PM

Small thing, but I want to avoid confusion. 3/8" PEX has a 0.5" OD. 1/2" PEX has a 0.625" OD.

 

'Doh! Yeah, 3/8" PEX is the stuff I use. Always get them confused.


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#12 jwasko

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Posted 16 October 2016 - 10:37 AM

This thread has some catch design ideas. It's similar to the catch used in Boltsniper's followup to the FAR, the SCAR-N.

 

Also, if you are set on using a wood dowel for the plunger rod you may want to drill some holes into it to remove some material/lighten it.

 

 

By the way, have you checked out Boltsniper's designs post-FAR? (click "image archive" near the top of the linked pages to see pictures)

http://nerfhaven.com...r-n-rifle-bs-8/ (SCAR-N: improved FAR, pump action)

http://nerfhaven.com...ctical-sidearm/ (NTS: pistol-sized, did not use shells)


Edited by jwasko, 16 October 2016 - 10:47 AM.

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#13 TulipMama

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Posted 17 October 2016 - 09:22 AM

This thread has some catch design ideas. It's similar to the catch used in Boltsniper's followup to the FAR, the SCAR-N.

 

Also, if you are set on using a wood dowel for the plunger rod you may want to drill some holes into it to remove some material/lighten it.

 

 

By the way, have you checked out Boltsniper's designs post-FAR? (click "image archive" near the top of the linked pages to see pictures)

http://nerfhaven.com...r-n-rifle-bs-8/ (SCAR-N: improved FAR, pump action)

http://nerfhaven.com...ctical-sidearm/ (NTS: pistol-sized, did not use shells)

 

Thanks Jwasko, I had seen a few of these forums in my searches, but I didn't know how to call up old pics that didn't show up. The pistol is very intriguing, but I don't know how the slide caught and pulled the bolt/plunger back without a long slot down the body, which would ruin the plunger seal. The write up on Boltsniper's site doesn't appear to still be up, so I can't figure that one out o.O 

 

Could somebody post a quick write-up of this pistol? It seems to be 90% of what I'm trying to design with Stacy.


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#14 Draconis

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Posted 17 October 2016 - 11:10 AM

 

I understand that. Home depot has a product they call 1/2" Pex, but it is the OD that is 0.5" (I called and one of the associates was kind enough to measure it for me) and I am looking for a product with a 5/8" OD, which they don't seem to have in lengths that I would consider reasonable.

Okay, I don't want to argue with you, but you are incorrect, and so is the associate.  I not only worked at Home Depot, but I continue to be very familiar with the plumbing aisles, mostly due to nerf projects.  Plumbing pipe and tube are never referred to by the OD.  Yes, it is possible that the 3/8" PEX was mislabeled or placed in the section for the 1/2", and yes, I would expect the employee to know better.


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#15 TulipMama

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Posted 17 October 2016 - 12:04 PM

Okay, I don't want to argue with you, but you are incorrect, and so is the associate.  I not only worked at Home Depot, but I continue to be very familiar with the plumbing aisles, mostly due to nerf projects.  Plumbing pipe and tube are never referred to by the OD.  Yes, it is possible that the 3/8" PEX was mislabeled or placed in the section for the 1/2", and yes, I would expect the employee to know better.

 

Fair enough, I will defer to you on this then, either way I have access to 1/2" PEX which makes my bolt design something I can at least physically acquire and make. Any thoughts on whether my bolt will be functional or not are appreciated, as always.

 

Also, forgot to mention, I'm thinking of revisiting the catch/trigger since looking at the pictures from Boltsniper's designs, but it shouldn't cause major changes.


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#16 Meaker VI

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Posted 17 October 2016 - 06:37 PM

 

Fair enough, I will defer to you on this then, either way I have access to 1/2" PEX which makes my bolt design something I can at least physically acquire and make. Any thoughts on whether my bolt will be functional or not are appreciated, as always.

 

Also, forgot to mention, I'm thinking of revisiting the catch/trigger since looking at the pictures from Boltsniper's designs, but it shouldn't cause major changes.

 

And to add weight to that, here's a link that backs him up. So I won't forget again either hopefully :S


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#17 jwasko

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Posted 17 October 2016 - 08:04 PM

Oh, by the way 1/2inch CPVC (that's copper-size PVC...it's beige) also has an actual outer diameter of 5/8inches. Inner diameter is variable, but usually a little less than 0.5 inches.


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#18 TulipMama

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Posted 25 October 2016 - 10:55 AM

Hello again,

 

So, after some thought, I basically re-designed the whole blaster, and it feels like I threw simplicity out the window, coming up with something I consider to be unquestionably complicated in nature. It does, however, fully capture most of my other concerns, which is I can make it with the tools I have (though I'll admit a drill press would be super handy), uses a standard nerf mag, and certainly looks the part as far as pistols go. I don't think it would take much reconfiguration to make it a rifle or shot gun style.

 

For your consideration: Stacy R2

 

stacy_operation_1__2_r2_by_the_tulip_mam

stacy_operation_3__4_r2_by_the_tulip_mam

stacy_r2_exploded_by_the_tulip_mama-dama

 

The idea is that the bolt and plunger are connected so that as the air is being compressed, the bolt is actioning forward to seat the dart before the air channel in the plunger, body and bolt line up, releasing the air to fire the dart. The bolt comes into the barrel and the air channels begin to line up well before 2mm (3/32" ish) before the end of the stroke, which is where the air pressure in the chamber would overpower the spring. The hollow PEX that the bolt and plunger are made of will be plugged up with sealant or dowels where needed, and the plunger itself is currently made up of various nested pvc/pex tubes and O-rings (which I'm trying to find parts to replace with a rubber washer set-up). The trigger is a Rainbow catch, and much, much simpler than the FAR trigger, so that's something I'm happy about. 

 

Now, I'm aware that some of the PEX and PVC parts won't mate as smoothly as I would like, but I've consigned my self to sanding things down since the likelihood of coming across 'magic' pvc is pretty slim in my area. Otherwise, my main concern is maintaining a decent seal during the initial plunger stroke since at the moment, I'm relying on the tight fit of the PEX and PVC to restrict my airflow in more than one place. 

 

Thoughts and suggestions would be greatly appreciated.


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#19 Meaker VI

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Posted 25 October 2016 - 02:06 PM

The idea is that the bolt and plunger are connected so that as the air is being compressed, the bolt is actioning forward to seat the dart before the air channel in the plunger, body and bolt line up, releasing the air to fire the dart. ...

 

Woah, the bolt and plunger release at the same time? Am I reading that right?

 

I'm not sure that's a good idea. Adding a second catch and a return spring on the bolt would do it as well and wouldn't require your strokes to line up perfectly every time.

 

What size plunger tube are you using? A dash-216 O-ring fits perfectly in 1-1/4" Sch. 40 PVC, and the Mark-8 has instructions for a rubber washer head in the same PT.


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#20 TulipMama

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Posted 25 October 2016 - 02:55 PM

 

Woah, the bolt and plunger release at the same time? Am I reading that right?

 

I'm not sure that's a good idea. Adding a second catch and a return spring on the bolt would do it as well and wouldn't require your strokes to line up perfectly every time.

 

What size plunger tube are you using? A dash-216 O-ring fits perfectly in 1-1/4" Sch. 40 PVC, and the Mark-8 has instructions for a rubber washer head in the same PT.

 

Ya, I'm really curious to see if this single action bolt/plunger release works reliably, if at all. I'm a little shy to go out and get the parts without some feed back on things that I'm missing since at this point I've already wasted some materials and time on a design that doesn't work, and I've basically thrown out my old design without even trying to build it. 

 

I'm using 1" PVC for the main plunger body, which is honestly why I'm having such a hard time finding a rubber washer that'll do the job. 1" OD washers are actually a bit undersized on 1" PVC which measures in at 1.05" roughly. 


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#21 jwasko

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Posted 25 October 2016 - 07:25 PM

If I understand your R2 design correctly you are using a spring to compress air via a piston/plunger, and then release it all at once the bolt has closed the breech? That's really cool, interesting, and some food for thought.

 

But I don't think you actually need to do something so precise as all that. You could instead have the bolt slide forward immediately after priming. One way to do this would be to cut a slot in the plunger rod like in the Tornadobow. So you would pull back both the bolt and the plunger, then when you let go the bolt is slid forward by a light return spring.

 

Also if you are worried about the bolt being pushed back by air pressure during firing (like in Boltsniper's FAR) you could have the trigger interface with it just before it releases the catch. When you release the trigger, the bolt will be free to be pulled backwards along with the plunger.

 

Oh, and since the dart isn't going into the bolt you shouldn't need the "half pipe" section of the bolt. You'd be better off with a cylinder or a cone at the front to simply push the dart forward into the barrel. You'll need to use a tighter barrel than 1/2" PVC by the way (you are using micro darts/elites right?)


Edited by jwasko, 25 October 2016 - 07:53 PM.

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#22 TulipMama

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Posted 26 October 2016 - 06:02 AM

If I understand your R2 design correctly you are using a spring to compress air via a piston/plunger, and then release it all at once the bolt has closed the breech? That's really cool, interesting, and some food for thought.

 

But I don't think you actually need to do something so precise as all that. You could instead have the bolt slide forward immediately after priming. One way to do this would be to cut a slot in the plunger rod like in the Tornadobow. So you would pull back both the bolt and the plunger, then when you let go the bolt is slid forward by a light return spring.

 

Also if you are worried about the bolt being pushed back by air pressure during firing (like in Boltsniper's FAR) you could have the trigger interface with it just before it releases the catch. When you release the trigger, the bolt will be free to be pulled backwards along with the plunger.

 

Oh, and since the dart isn't going into the bolt you shouldn't need the "half pipe" section of the bolt. You'd be better off with a cylinder or a cone at the front to simply push the dart forward into the barrel. You'll need to use a tighter barrel than 1/2" PVC by the way (you are using micro darts/elites right?)

 

 

I had thought of doing exactly that, putting a spring just forward of the trigger inside the bolt and securing it with a screw so that when released, the bolt would slide forward and seat the dart while the plunger arm remained secure until firing. The reason I didn't pursue it was because I didn't trust a weaker spring to be able to force its' way through the mag, overcome all that friction and pick up a dart. I have a Retaliator and I have to apply considerable force to push the action forward, I don't feel like a weaker spring would be able to overcome that force reliably. Not to mention the added cost of the spring, which is already the most expensive part of this build. I may put a slot in the plunger arm and manually push the bolt closed, which should actually improve the spring efficiency for firing as it doesn't have to overcome all that friction from seating the dart, but I'll leave that as something to test after trying this single action plunger/bolt hybrid. I can always cut the slot afterward, but I am VERY curious to see if this works at all.

 

Just a quick question on the spring by the way. In this model I'm using a [k26] spring from Mcmaster cut to 4.75" (I realize I could get away with 5.5", but I'm being conservative), which in and of itself is fairly cheap (a pkg of 5, 11" springs for $12-ish) but the shipping is literally more expensive than the actual spring. Is that just the unfortunate truth of getting this spring, or is there a more cost effective means of getting one? Is there an analogous spring that's less expensive to acquire?

 

Anyway, back to Mr. Jwasko's points, as for the bolt being pushed back, I actually hadn't even considered that a possibility. With the current design, I doubt the air released would be able to push the bolt back just based on the spring keeping it forward, but if I were to manually push the bolt forward, I would have to do something. A secondary catch that engages when the trigger is pulled if a fantastic idea, and I'll definitely keep it in mind should I go that route.

 

The 'half pipe' of the bolt is actually serving several functions in this design, and while I would love to be rid of the damnable thing (not looking forward to cutting that) its utility outweighs its annoyances. As it stands, it acts as a 'guide' between the two sections of 1/2" pipe that make up the barrel and breach, cutting a 1/2" pipe that would accommodate the mag would be even more annoying and basically have a 1/4" 'sliver' running between the two pieces. Secondly, it's a sort of secondary securing system for the mag since a 5/8" OD fits very snuggly inside that dart retainer at the top, and the mag will 'snap' over the edges of a 5/8" dowel without issue. It makes the mag harder to remove for reloading, but not too hard in my opinion. Lastly, it makes the 1/2" barrel a little 'tighter' since, as you say, a 1/2" pvc pipe is too loose to house an elite dart.

 

I don't have any better options for a barrel though since the dart is just a little over 1/2" and there is no PEX, CPVC or PVC pipes, or fittings that would have a tighter ID. Right now I'm sort of stuck on that. If I could make my own darts, I'd just use the PEX bolt and scoop them right into a matching barrel. The closest thing I can think to do is take the other half of the 'half pipe' part of my bolt and try to sand down the ID so that I can place it in the barrel to shore up the ID difference. Any other options for a barrel with an ID just over 1/2"?

 

EDIT:

I completely forgot about 5/8" PEX, which has a 0.584" ID, where the Elite dart has a 0.511" OD, so they are much closer. There's still roughly 2mm clearance, which is quite a bit, but I might be able to make that up with a duct tape liner?


Edited by TulipMama, 26 October 2016 - 11:09 AM.

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#23 Meaker VI

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Posted 26 October 2016 - 11:57 AM

Just a quick question on the spring by the way. In this model I'm using a [k26] spring from Mcmaster cut to 4.75" (I realize I could get away with 5.5", but I'm being conservative), which in and of itself is fairly cheap (a pkg of 5, 11" springs for $12-ish) but the shipping is literally more expensive than the actual spring. Is that just the unfortunate truth of getting this spring, or is there a more cost effective means of getting one? Is there an analogous spring that's less expensive to acquire?

 
Yeah, that's the trouble with Mcmaster. You might be able to ask them to standard-ship it or something, it seems like they've always 2-day shipped for me. If you're making an order, it is almost always worth while to throw some other stuff you've been needing into the order so you're not getting single parts 2-day shipped to you *and* most of the time the springs need a bigger box than other stuff you'd need in the build (orings/seals, lubricant maybe, hardware).
 
The only way to get the [k26] from someone other than Mcmaster is to buy it off someone else in the NIC or order direct from the manufacturer - Langley had figured out what company that was at one point. I think they've got a minimum order though. You could also order one of the longer springs and cut them down - IIRC the k35 is one that comes 36" long and is cheaper but performs the same as a [k25], but check the spring database before ordering.
 

The 'half pipe' of the bolt is actually serving several functions in this design, and while I would love to be rid of the damnable thing (not looking forward to cutting that) its utility outweighs its annoyances. As it stands, it acts as a 'guide' between the two sections of 1/2" pipe that make up the barrel and breach, cutting a 1/2" pipe that would accommodate the mag would be even more annoying and basically have a 1/4" 'sliver' running between the two pieces. Secondly, it's a sort of secondary securing system for the mag since a 5/8" OD fits very snuggly inside that dart retainer at the top, and the mag will 'snap' over the edges of a 5/8" dowel without issue. It makes the mag harder to remove for reloading, but not too hard in my opinion. Lastly, it makes the 1/2" barrel a little 'tighter' since, as you say, a 1/2" pvc pipe is too loose to house an elite dart.
 
I don't have any better options for a barrel though since the dart is just a little over 1/2" and there is no PEX, CPVC or PVC pipes, or fittings that would have a tighter ID. Right now I'm sort of stuck on that. If I could make my own darts, I'd just use the PEX bolt and scoop them right into a matching barrel. The closest thing I can think to do is take the other half of the 'half pipe' part of my bolt and try to sand down the ID so that I can place it in the barrel to shore up the ID difference. Any other options for a barrel with an ID just over 1/2"?
 
EDIT:
I completely forgot about 5/8" PEX, which has a 0.584" ID, where the Elite dart has a 0.511" OD, so they are much closer. There's still roughly 2mm clearance, which is quite a bit, but I might be able to make that up with a duct tape liner?

You seem a bit stuck on reinventing the wheel. We've had many breeches for elite-caliber foam darts since the FAR - brass hobby tubing, CPVC/PEX, PETG tubing/PEX, and others that were more machined. Usually, the breech would have the cutout you show on one side or the other to keep the darts in the mag and aligned with the breech, but Captain Slug (and I, and a few others) is working on a setup that doesn't need that.

 

For barrels, your options are brass tubing, PETG (usually special ordered or purchased from someone here on the NIC like Draconis), 1/2" CPVC (though you'll need to sort through it to find an ideal fit), 1/2" Sch. 80 PVC (again, sorting probably required - it's also not always carried and may not be in the same place as regular PVC), aluminum tube ordered from Mcmaster, and a myriad of others. You should not try to line your barrels with anything to get them to fit, that is unlikely to work.


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#24 CaptainSlug

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Posted 26 October 2016 - 01:08 PM

The only way to get the k26 from someone other than Mcmaster is to buy it off someone else in the NIC or order direct from the manufacturer - Langley had figured out what company that was at one point. I think they've got a minimum order though.

https://www.springsf...on.php?part=614(K25)
https://www.springsf...on.php?part=615(K26)
 
Their minimum order is 5 pieces. Which is the minimum order quantity for the same springs from McMaster too.

Captain Slug (and I, and a few others) is working on a setup that doesn't need that.

My setup is completely done. I'm currently just finishing up the testing routine with the chronometer I just got and I have one last detail I want to tweak to reduce the likelihood of the bolt getting stuck inside the plunger tube.
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#25 Silly

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Posted 28 October 2016 - 12:04 PM

Question for tulip: would/does the current iteration of the design work with 16,25,and 35 dart drums?
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