21 replies to this topic

[Carbon]

The hardboard version of the turret was a test to see if the craft foam seal was a workable solution. However, we all know that circles are where it's at for turrets. We also all know that it's a pain to cut them, so the best solution is one with off-the-shelf parts. So, here's the revised SNAP-turret...



The reworking of the turret had me going back to where I should have started: the PVC aisle. I had originally intended to build the turret out of two 3" drain endcaps (flat ended endcaps), but those apparently don't exist. However, I found something way better:


Does this part scream "turret" or what? It's the same diameter as the OD of 3" PVC. The inner socket fits1/2" sched 40, or, as luck would have it, 1/2" CPVC endcaps. The inner hole is a perfect fit for 1/2" CPVC. The outer holes are a near perfect fit for 19/32" brass. I just had to tcut off the nub at the top.

EDIT: General Cole reminded me that I should probably say what this is called. It's a 1/2" schedule 80 socket pipe flange, and I found it in with all the other PVC at Menard's. (I didn't see it at Home Depot, but I didn't ask, either.)

Here's the other half of the equation:


This is an outlet cover, 3" diameter, perfect match to the pipe flange. I had traced my air and center hole already. I found this part at Home Depot (but not at Menard's, oddly enough).

Rear view:


I added a spring, and used another endcap to hold it on. The air delivery tube is superglued, and then hot glue sealed. The hole is very close to the edge of the cap, so I had to cut off a side of the tube, to make it fully cover the hole.

Here's the exploded view (minus barrels):


I usually tend to post works in progress, so I have a few things to finish:
1. Add a 3" endcap over the front to support the barrels, give a good surface to grab, and give a place to mount the indexing system
2. Install the indexing system. I have one designed, which will give a positive feel for when the barrel is aligned with the airhole.
3. Get another barrel. I'm still out of brass. Hopefully this weekend I can get another couple sticks.
4. Cut a larger hole in the bottom for rear loading. The bottom barrel will be loadable.

As far as future plans, I think I'd eventually like to try making this an 8 barrel system, but I'm not sure it'll be enough foam left to make a seal. I'll try that later. Also, I intend to make a scaled down SNAP for this to live on: breech barrel for range, 4 shot turret for close action.

Edited by Carbon, 25 July 2007 - 07:51 AM.

[General Cole]

OMG! I like it. No more 2K turrets, sorry Falcon. Do you know what the rotational piece is called, the one that screamed Turret?

[Carbon]

OMG! I like it. No more 2K turrets, sorry Falcon. Do you know what the rotational piece is called, the one that screamed Turret?

It's a 1/2" schedule 80 socket pipe flange (I have no idea what they're really for). They come in other varieties and sizes (threads, etc) as well.

[General Cole]

Thats awsome. I have been working on a turret, so now I can! Thanks Carbon!

[NerfMonkey]

Looks exactly like a 2k turret. Nice.

Is the spring just to push the back piece of the turret against the barrels for a better seal?

[CD-R]

Wow, nice. I always thought something like this was possible, but laziness prevented me from trying it. Good job.
P.S. you should try working with different sealing materials and springs to see which works best.

[Carbon]

Is the spring just to push the back piece of the turret against the barrels for a better seal?

Yup...that came from suggestions from the original thread. It'll definitely help maintain a seal better than the original bolt and nut.

A definite advantage a 2k turret has is size...this thing is pretty big. A Falconed Splitfire would be...bulky. But I'm looking forward to incorporating this into other homemades...clips have been frustrating me.

I'll post some relative size pictures tonight.

[Retiate]

Wow, that piece is... Perfect.
Nice job, it's lookin' pretty awsome.
Do you have to manually line up the barrels? Or did you put in something so they click into place like on a 2k or SM1500 turret?

[Prometheus]

To conserve your foam, don't seal the whole turret. Just the air opening thinger (where the air goes through). Use thin cardboard (shoe/cereal box) for the rest if you need it built up. Just an idea I'd thought I'd toss out there.

[Thom]

There probably isn't much need to conserve the craft foam; it's like 79¢/sheet.

[Carbon]

Do you have to manually line up the barrels? Or did you put in something so they click into place like on a 2k or SM1500 turret?

It does now (thanks for the lead in).

The turret is, for all intents and purposes, finished....I just need to tweak it out and affix the barrels a bit better. Here's how it's looking now:


Looking at the back, you can see the hole for rear loading of the barrels:


A view of the cowling (still need to get better barrels, and permenantly affix them...straight.)


A view of the indexing system: it uses a spring loaded ball bearing.

Here's how it works: to start, I lined one one barrel, and drilled a small hole through both the cowlng and the outlet cover. I then rotated to the next barrel, lined it up, and then drilled another hole through the outlet, through the same hole in the cowling.

Once that was done, I enlarged the outer hole so I could wedge a Bic pen into it. The inner holes were slighly enlarged and beveled so the ball bearing could drop into it about halfway, and then smoothly rotate out.

The index itself is a half inch of Bic pen with a small pen spring inside it, and a slingshot ball at the end. The spring presses the ball against the outlet. The ball will snap into place when a hole is below it...which is aligned with the barrels. However, because of the loading hole, I need to install a stop so I can't rotate past that point and lose my spring.

Oh yeah, size comparison...with a 2k turret.


It's not exactly svelte.

[NiteWalker]

At that size couldn't you add more barrels? Im sure you could at least squeeze 2-4 more barrels in there. Great job at making a locking mechanism for the turret. That was always the weakpoint of homemade turrets and lowered the potential ROF, but this solves it.

[General Cole]

Did you see the part that makes the barrels? It only has FOUR holes.

[Carbon]

The turret plate comes with four holes, but it'd be a pretty trivial matter to drill an extra four. You're right, NiteWalker, there's room for them, and it's definitely a goal...I just want to make sure that I have the four barrels sealing well before I try and add more. The whole thing disassembles quickly, so I can rip it apart and add indexing and barrel holes quickly. It'll also be an experiment, because i'm not sure that the craft foam could maintain as good of a seal if the foam area between barrels is decreased.

That, and I want to lay my hands on some PETG for barreling this with 8, as opposed to trying to get that much brass.

[Carbon]

An update on the finalizing progress of the turret:

I sealed in the barrels today, and discovered that my ranges were pathetic...with the darts sometimes not even leaving the barrel. I then discovered that the bottom of the turret plate isn't flat, even if it appears that way. The concentric grooves that were carved into it also hid the slight depressions in between each barrel hole. So, it needed about 20 minutes with increasingly fine sandpaper to get it reasonably flat and smooth. There are still little dents in between each barrel...but the immediate area around each barrel is flat. Improvements are immediate and dramatic: i'm now hitting the wall at the opposite end of my apartment with no drop (I'm guessing 60 feet range at this point...the wall is 40 feet or so).

The barrels are held in pretty simply: a healthy amount of teflon tape, and then sealed with a bead of hot glue. The air tube will eventually need plumber's goop or epoxy, though, as it holds the weight of the entire assembly. It's never fallen off, but it seems to get pinhole leaks.

Official ranges later on.

[nerfer34]

An update on the finalizing progress of the turret:

I sealed in the barrels today, and discovered that my ranges were pathetic...

Hey atleast you're being honest.

It's amazing how the 2k turret is so small, compact , and simply made. But performs with perfection.

Also do you think you could edit your first post and move one of the first 2 pictures below the other one? SO that way we don't need to side scroll?

Thanks

[Carbon]

It's easier to be honest when you can say you already fixed it.

Ranges: (low of 52 and high of 75 tossed out)

55'
57'
62'
65'
65'
65'
65'
67'
72'
72'
72'

The plunger is hitting a lot harder with the turret as opposed to the breech barrel I'm usually using. There could be several reasons:

1) Losing a lot of pressure to the turret seal
2) Barrels too short

At any rate, it's a problem for another day. If I can lay my hands on enough barrel material, I'm still going to try and add four more barrels, at which time I may try longer barrels.

Edited by Carbon, 04 August 2007 - 01:34 PM.

[FoxTrotter]

The turret looks pretty heavy and appears to be weighing down the gun, being slightly crooked, did you intend to do this?

[Carbon]

Ah, I see what you mean.

The slight down-tilt comes from the cut I made on the .5" PVC it's mounted to...it isn't a perfect cut, so the turret doesn't sit entirely straight. It's due to imprecise work, not the weight...although, it's not exactly light. I think the weight/performance ratio will be better once the additional 4 turrets get put in.

[All Star]

Nice carbon! Just wondering though: Are the barrells very stable, and if not, do you have any tip on how to make them more stable? I am looking at constructing a homemade with a turret.



Thanks,


All Star

[Carbon]

I gave the brass 7 or 8 turns of teflon tape, and then jammed it into the turret base. I then sealed it up with glue. If you wanted to make it a little more durable, you could probably add a ring of .5" PVC over the barrels (perfect fit around 19/32" brass), which would then give you a better surface to glue or otherwise attact to the turret. I'll also probably be adding some manner of support ring for the barrels, beyond the 1" endcap I pushed on the end (perfect fit over the center of the turret base).

[All Star]

Thanks for the advise Carbon!