21 replies to this topic

[Dremz3]

After revising Ace's snap carbine, and seeing NOM's version, I decided to make one. However, I only had [k26] springs with me, so I made a snap carbine with a [k26]. Plus, I believe [k26] springs are more powerful.
Here is the finished product:


In order to add a full 11 in [k26] with a 4 in compression, I had to make the carbine pretty long. I actually made two, because the first one did not have a 7 in draw. The piston is longer, and in order for the nail to ride along the piston i had to make the pvc continue on the piston.



I also made 1/2 in cpvc pegs for the [k26] to wrap on so that it does not fly everywhere.



The stock also has a peg:







Blaster primed:



Another picture of the entire blaster:



Overall, if you have a [k26] and want to make a snap carbine, you can. I'm getting 100 ft flat with stefans, and 130 ft - 150 ft angled. The only problem I have with snaps in general, is clothespin triggers. They are too weak to hold a [k26], full compression. Other than that, snap carbines are fun to make! (By the way this is my first post, yet I would love to answer any questions you have)

[Siarnaq]

The only problem I have with snaps in general, is clothespin triggers. They are too weak to hold a [k26], full compression.

That's a problem with your trigger in particular, not the design of the CPT itself. They are a pain to get right though. Actually, I have heard of troubles with this in the Snap Carbine where they didn't occur in a normal SnapBow, so maybe using a [k26] actually was just too much for that clothespin.

I've been wondering recently why Snap Carbines didn't just use a [k26] in the first place and have a dowel for the priming handle screwed onto the piston without sticking it through. You could then nest the [k26] inside the piston. It would allow for the whole thing to be much shorter. There may be something I'm missing though.

EDIT: I'm curious, what is it you did with the threaded fittings on the barrel?

EDIT2: Sorry, I was apparently being unclear- I meant fastening the priming handle so that it was not sticking through the piston, similarly to how the main handle is usually attached to a RainBow.

Edited by Siarnaq, 01 April 2012 - 10:11 AM.

[Dremz3]

That is probably true, and part of it is because I can't seem to find any strong clothespins any where, so both my snap bow and my snap carbine are hard to catch. I had to attach a catch spring to the trigger to make it catch a little.
The one reason I can think of why people don't use that method, is because the priming handle is placed inside the piston and thus it would get in the way of the [k26].
If your asking about the pegs, then the piston itself is 1 in pvc, then 3/4 in pvc, then 1/2 in pvc, and finally 1/2 in cpvc. I had to dremel out the middle of each to fit inside each other.

[Spud Spudoni]

Damn! You beat me to it! I was about to try a [k26] spring in a Carbine, but it seems you arleady achieved that. Well done. As for as the spring itself, I see it bending the PVC at some point, or over time. The spring may then fly out pf the PC, and hit you, or damage the blaster. I would suggest putting some sort of PVC, or cover on the bolt slot to eliminate this.
As far as the trigger, it may be because your nail is too long, your clothespin is cut too short, or yes, the clothespin may not be strong enough to support the spring. Wal-Mart has a big pack of hefty plastic clothespins that are slightly bigger. This may help you, and with a little E-Putty, your blaster should preform better.
Hope to see more of your work soon.

[hamoidar]

Problems with your trigger: One, you need something stronger than hot-glue to hold it on. Two, as Spud said, you need to get a plastic clothespin. Three, in your pictures, it looks as though you nail/catch is leaning forward. This is most likely caused by the high-powered spring making the nail dig into the pvc. A good fix would be to use a small piece of copper tubing, with the nail nested inside, to act a a sort of bearing surface for the catch pin. Sort of like Boltsnipers FAR, were he uses brass tubing. (http://www.boltsnipe...m/BS-5/BS5.htm' class='bbc_url' title='External link' rel='nofollow external'>boltsniper)

[Siarnaq]

One, you need something stronger than hot-glue to hold it on.

Two, as Spud said, you need to get a plastic clothespin.

Three, in your pictures, it looks as though you nail/catch is leaning forward.

1. Hotglue holds just fine, although a ziptie definitely helps.

2. Lots of people still use wooden clothespins for their Snaps- Louiec3 and Carbon are two. They're super annoying to drill through though.

3. With wooden clothespins, this can be a problem. Carbon explains here. This is probably the problem he's having with his triggers. Stronger clothespins are far more forgiving in this area.

Edit blatantly avoiding the FNG post limit: Hot glue is okay for holding on a CPT- It's not going to be exposed to much force. A ziptie really helps though. Also, I never said that wooden clothespins were better- they definitely aren't. I was just saying that they will work if you don't have plastic ones.

Edited by Siarnaq, 01 April 2012 - 04:33 PM.

[hamoidar]

1. Hotglue holds just fine, although a ziptie definitely helps.

2. Lots of people still use wooden clothespins for their Snaps- Louiec3 and Carbon are two. They're super annoying to drill through though.

3. With wooden clothespins, this can be a problem. Carbon explains here. This is probably the problem he's having with his triggers. Stronger clothespins are far more forgiving in this area.

Hot glue does not hold "just fine" It cannot stand up to repeated shock, or fluctuating heat. Just because people still use wooden clothespins doesn't mean they are better than plastic ones. Wood is prone to splitting, whereas plastic is not.

[Carbon]

The only problem I have with snaps in general, is clothespin triggers. They are too weak to hold a [k26], full compression.

The clothespin does zero work in resisting the force of the plunger. It's all done by the nail and the wall of the plunger tube.

Just because people still use wooden clothespins doesn't mean they are better than plastic ones. Wood is prone to splitting, whereas plastic is not.

And plastic isn't any better than wood. Personally, I've never had a wooden clothespin split, and I find them easier to machine...I've switched back to wood after using plastic for a few years.

Really, it makes no difference, and comes down to personal building preference.

[hamoidar]

The clothespin does zero work in resisting the force of the plunger. It's all done by the nail and the wall of the plunger tube.

Exactly, both of those have limited wear resistance and will eventually break. Of course, everything in any gun will, eventually, break. I personally favor SGnerf's PVC rainbow catch, which I have used for years, and have never had a problem.

[Curly]

Personally I've had terrible luck finding clothespins made of anything that have strong springs and are durable, even with e-putty filling. So I bought a pack of large clothespins with good springs and make the CPT out of plastic sheets like Ice recommended in a video. I only have acrylic but polycarb is much better.

I used a pump-SNAP with one and it broke after several rounds of being awesome. The reason was 100% user error because I shaved off far to much material to make room for the end of the spring so I was putting all that pressure on >1/8" of material. Further confirming what Carbon said, the blaster stayed primed when the trigger broke, leaving only the nail. Even if Ice's technique is doomed to fail, I can make 2-3 of these in the time it takes to mod a plastic clothespin and for cheaper. Due to the large size of the clothespins I bought I could easily stack two layers of plastic to make it near immortal.

Also, because homemade clothespins are very simple they're great candidates for epoxy casting, though the durability is probably similar to polycarbonate.

[Carbon]

Exactly, both of those have limited wear resistance and will eventually break.

And eventually the Sun will supernova, but it's not a circumstance you really have to worry about. A standard SNAPbow is built around a [k26], and the plunger head will wear out way before the nail and nail hole will. A CPT can handle a [k26] just fine, it just takes some dialing in.

Edited by Carbon, 01 April 2012 - 09:57 PM.

[Pause]

Anyways, back to the mod homemade.

I really like this version of the Carbine Dremz. Especially the stock.
My question is, how long is the blaster? Counting the barrel.

Edited by Pause, 02 April 2012 - 05:08 PM.

[Zorns Lemma]

Having a large exposed section of buckling spring seems like the perfect design for the average end user here.

I support your eugenics project.

[Dremz3]

Sorry I couldn't answer any questions yesterday, I'm stuck with this two post limit.
Siarnaq:
I can't think of a way to fasten the priming handle to the piston without making it go through the piston, because it would be much less sturdy.
Spud:
This gun was just for fun so I'm not going to use it very often, therefore I don't think the pvc will bend and the [k26] will fly out. However, a plate over it would never be a bad idea.

As for my trigger:
It is a standard clothespin trigger with bamboo wood which i find to be much stronger than regular wood clothespins. The reason it is not a plastic clothespin is because I cannot find plastic ones sold anywhere. If I had one, I would definitely use it. The trigger is screwed in with two screws into the pvc and also has hot glue on the outside. The clothespin spring was too weak, and the piston would push the nail back out of the piston hole, so I added a catch spring which is nailed in and hot glued. Overall, there is no problem with the way I made my trigger other than that if you look at the first pic, you will notice that it is slanted to the left and that is because the handle and the stock are actually slanted, not the trigger (I made a mistake putting them on). This however is not the reason my trigger does not catch.

Pause:
The petg barrel is 12 inches long. The entire gun including the barrel is 40 1/2 inches.

Zorn:
Not sure what you mean by average end user?
and are you saying that my nerf gun design is starting a perfect race?

[Siarnaq]

Sorry I couldn't answer any questions yesterday, I'm stuck with this two post limit.

You could edit answers to some of the questions into the OP.

Siarnaq:
I can't think of a way to fasten the priming handle to the piston without making it go through the piston, because it would be much less sturdy.

You would definitely need to use something solid, like a 5/8" dowel rod. The way I'd do it is epoxy it in place on the piston, and then drill a hole on the opposite side. That way you could fit a scredriver/drillbit in to drill a hole through both the piston and the dowel, that you could then run a screw through. You'd have to use a relatively big screw; I'd probably use 1/4", though that might be a little big. It would be a bit less sturdy and harder to do, yeah, but IMO it'd be worth it to eliminate all that unnecessary length. It would also help avert the exposed length of buckling spring that Zorn mentioned, but if having it as a eugenics project is your goal that's probably a bad thing, hehe.

[Dremz3]

Siarnaq:
After thinking about for a while, your idea might not work. Due to the spring going inside the piston, the piston will move further back including the seal, and in turn this might lead to the seal being open to the priming bar slot causing the air to leak out. It might work if you get the right dimensions though.

[Siarnaq]

Siarnaq:
After thinking about for a while, your idea might not work. Due to the spring going inside the piston, the piston will move further back including the seal, and in turn this might lead to the seal being open to the priming bar slot causing the air to leak out. It might work if you get the right dimensions though.

Getting the dimensions right shouldn't be all that difficult. I'll build one sometime soon and see- I have it planned out, just gotta get the parts.

EDIT: After thinking about it some more, I figured out why people don't do it that way- the only thing it would reduce the length of is the stock! Derp.

EDIT2: I was unclear there. I meant that because the spring can compress inside the piston, the spring rest is moved a bit farther forward. But that's all that happens. I drew several crappy paint diagrams if those would help.

Edited by Siarnaq, 04 April 2012 - 08:00 AM.

[Dremz3]

The gun would still be long even with the spring in the piston, especially if you want a 7 inch draw. Why the stock? It has nothing to do with the stock.

[Spud Spudoni]

You would definitely need to use something solid, like a 5/8" dowel rod. The way I'd do it is epoxy it in place on the piston, and then drill a hole on the opposite side. That way you could fit a scredriver/drillbit in to drill a hole through both the piston and the dowel, that you could then run a screw through. You'd have to use a relatively big screw; I'd probably use 1/4", though that might be a little big.

I seriously doubt that this could work at all. I don't know if you know the strength of PVC, but it does have limits. Even with the epoxy, and screw, the PVC around this area may start to give, overtime breaking off. Or your epoxy could give out, and the head of the screw would pull it's way out of the hole. Use Nerf's Longshot as an example. People have their boltsleds breaking all the time, just because the bolt is pulled from one side, and that's all the way through the boltsled, unlike your idea. If you say it's possible, then try it and prove me wrong! However that seems like a slim chance to happen.

[Siarnaq]

I seriously doubt that this could work at all. I don't know if you know the strength of PVC, but it does have limits. Even with the epoxy, and screw, the PVC around this area may start to give, overtime breaking off. Or your epoxy could give out, and the head of the screw would pull it's way out of the hole. Use Nerf's Longshot as an example. People have their boltsleds breaking all the time, just because the bolt is pulled from one side, and that's all the way through the boltsled, unlike your idea. If you say it's possible, then try it and prove me wrong! However that seems like a slim chance to happen.

Take a look at the quixote's priming mechanism. If you use a large enough scerw, combined with the epoxy you probably won't have problems. It's a moot point anyway- nesting the spring inside the piston would not allow signifcant shortening of the blaster.

[Spud Spudoni]

Take a look at the quixote's priming mechanism. If you use a large enough scerw, combined with the epoxy you probably won't have problems. It's a moot point anyway- nesting the spring inside the piston would not allow signifcant shortening of the blaster.

Considering that the screw he used is barely an inch long, I would have no doubt it would hold. Since the screw you would need would be near 5 inches, the length of it would be the problem. Same thing happens when you try to ben a 4' section of PVC, and a 5'' section of PVC.

[Dremz3]

Overall, I really see no point in going through all that trouble to put the [k26] in the piston when the 2-3 inches you save won't bother anyone.