One day I got this idea of a really simple bolt action mechanism so I drew it up in Sketchup and thought to myself, well that can't be that hard to actually build.
So this is my Bolt action (mini) spud gun project, I have gotten as far as to get the bolt action mechanism to actually work as intended and the gun isn't that far from being done but progress is kinda slow so I'll update this whenever I feel like building on it.
Pictures:
This is the drawing that started it all:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_sketchup.png[/img]
As you (might) see the gun has an air tank in the back with a type of homebuilt valve, it works on the principle that when the tank is under pressure the disc (green with two small holes) is pressing on the barrel inside of the tube because the pressure is higher in the tube than the pressure in the barrel.
When you want to fire the gun you press the trigger which in this case is a pneumatic blow gun and it let's out air behind the disc which leaves lower pressure behind the disc thus making it move backwards and letting the air out via the barrel as a result.
It kind of works like a sprinkler valve:
[url]http://www.spudtech.com/content.asp?id=21[/url]
The Cartridge mechanism is basically the same as the real version but I moved around a couple of pieces.
So how does this amazing cartridge mechanism work?!
Well, I have tried to illustrate it as best as I can:
[img]http://i102.photobucket.com/albums/m117/nismo299/Bolt_funtion_smaller.png[/img]
The next few pictures is where I have tried to describe how it's built:
[img]http://i102.photobucket.com/albums/m117/nismo299/boltaction1_smaller_measure.jpg[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/Boltaction2_smaller.png[/img]
Lastly, here's a couple of crappy pictures how it looks right now:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_bad_pic.png[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/Bolt_Action_Dissassembled.png[/img]
I'll try to get some videos of it cycling this week and maybe some better pictures.
Awesome.
god, why wont you just make it automatic?
[QUOTE=papu2;29257228]god, why wont you just make it automatic?[/QUOTE]
Is that a joke? :raise:
Automatic firepower only came around when cartridge-based firearms came around, because they can use the principles of gas operated or recoil operated firing mechanisms wherin they harness the power of expanding gases to operate the bolt automatically.
Potatoes don't explode so obviously that wouldn't work.
If that is a joke, disregard the above post :v:
[QUOTE=papu2;29257228]god, why wont you just make it automatic?[/QUOTE]
You have to understand as hypno-toad kinda explained already that to make it automatic I would have to experiment with either recoil based cycling (which to me seems impossible with pneumatic) or a gas operated design which also seems unlikely with the kind of energy involved and no precision parts and even beyond that I would have to have an air supply able to give constant air in short bursts which I don't have.
[QUOTE=hypno-toad;29257658]
Potatoes don't explode so obviously that wouldn't work.
[/QUOTE]
"Fully automatic" doesn't have anything to to with the propulsion method of the projectile, the rate of fire, or even the mechanism by which the gun is loaded and fired, it just implies that the gun can continuously fire and reload itself mechanically with simply a trigger input from the operator.
Fully automatic tennis ball cannon (Which operates on the same principles as a spud cannon)
[media]
[url]http://www.youtube.com/watch?v=aIox-FH2yVY&feature=related[/url]
[/media]
Then the answer is obvious isn't? Because making an automatic system would be very difficult in comparison to bolt action.
[QUOTE=Timebomb575;29282119]
Fully automatic tennis ball cannon (Which operates on the same principles as a spud cannon)
[media]
[url]http://www.youtube.com/watch?v=aIox-FH2yVY&feature=related[/url]
[/media][/QUOTE]
I'm sorry but that is crap. All that time wasted for that. Impressive design and all but just christ, what's the point.
[QUOTE=joe588;29301204]I'm sorry but that is crap. All that time wasted for that. Impressive design and all but just christ, what's the point.[/QUOTE]
Tennis practice?
Jesus christ shut the fuck up. You obviously don't know how rewarding it is to get something like that finished. Even if it's shit the fact that it works like you imagined is a reward in itself.
[QUOTE=Hullu V3;29331698]Tennis practice?
Jesus christ shut the fuck up. You obviously don't know how rewarding it is to get something like that finished. Even if it's shit the fact that it works like you imagined is a reward in itself.[/QUOTE]
i doubt he imagined it to work like that.
[QUOTE=joe588;29331823]i doubt he imagined it to work like that.[/QUOTE]
What exactly are you basing this notion on
Update time.
This time it's some pictures of the air tank part of the gun and this part is kind of an ongoing experiment since I don't really know if it works yet.
Overall look of the tank:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_air_tank_valve.jpg[/img]
Opening the bottom end to see the valve plate:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_valve_plate_in.jpg[/img]
Without the valve plate:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_inside_air_tank.jpg[/img]
The valve plate itself:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_valve_plate.jpg[/img]
I think I might have to redo the plate since It's a bit too small and might not follow the air stream back when I press the trigger since a lot of air can escape on the sides, no biggie though I'll just use my drill as a lathe again...
I also took out the pneumatic air gun of the handle to take a picture of how I modified it:
[img]http://i102.photobucket.com/albums/m117/nismo299/bolt_action_air_gun.jpg[/img]
As you can see it's pretty heavily cut down to make it fit inside the handle and it now releases the air on top of it, this shouldn't be much of a problem since the air can easily escape in the handle and it's probably not going to be all that much air coming out of it.
It is also drilled and tapped to accept a standard BSPP 1/4" pipe fitting to work with my pneumatic fittings.
Also, an updated look on how the gun looks right now since I painted the barrel and also glued in holders for the spring which I right now use a rubber band on and it seems to work well:
[img]http://i102.photobucket.com/albums/m117/nismo299/Bolt_action_spud_gun_black.jpg[/img]
Last but not least here's a video of it cycling:
[media]http://www.youtube.com/watch?v=c8v-JKclVm8[/media]
Sneak edit:
I have kinda been working on this instead (people who have played TF2 will hopefully see what it is):
[img]http://i102.photobucket.com/albums/m117/nismo299/disp_huh.png[/img]
I can't just focus on one thing at a time
This is amazing, the cycling rounds is very sexy.
[QUOTE]
[img_thumb]http://img.ihack.se/images/10130366011011.png[/img_thumb]
[/QUOTE]
JIZZ JIZZ
This has inspired me to make one, going to home depot to pick up some supplys tomorrow after school ^_^
Im guesing this is a barrel sealing piston valve?
what PSI's are running it at?
Also check out [url]www.Spudfiles.com[/url] they and help you if you get into any trouble, post same damage pics to.
[QUOTE=Jimmaye;29486204]Im guesing this is a barrel sealing piston valve?
what PSI's are running it at?
Also check out [url]www.Spudfiles.com[/url] they and help you if you get into any trouble, post same damage pics to.[/QUOTE]
I had to read up on what a "barrel sealing piston valve" is but yeah that's what it is, I saw the design for it a long time ago and just built it out of memory.
I'm probably going to run it at 80-100psi, not overly impressive but it has worked good in the past and I feel pretty safe with that pressure.
I'll check out the site, Thanks.
/Edit: wow, there are some pretty impressive rifles on that site that's giving me ideas for the future.
Update:
You might remember the first "piston" I made for the guns homemade valve, well it was a bit small and kinda oval so I had to redo it.
At first I was going to just make another one but while looking for alternatives I found a hairspray bottle with almost the perfect measurements and it was just a matter of sawing off the bottom of the bottle and then using some large heat shrink tubing to get just the right diameter.
Sealing it to the barrel was just a matter of cutting out some rubber, lubing it up and screw it on.
I should note though that I did add some washers later because the rubber separated from the bolt on the first test fire.
Piston:
[img]http://i102.photobucket.com/albums/m117/nismo299/piston1.png[/img]
Backside:
[img]http://i102.photobucket.com/albums/m117/nismo299/piston2.png[/img]
In the air tank:
[img]http://i102.photobucket.com/albums/m117/nismo299/piston3.png[/img]
I will go through a short summary of my test fires this far:
1. With first piston: the piston did not move back from the back pressure, this could be caused by two things; either the piston was too small (which is likely) but I later learned that It probably was at least partly due to the pneumatic blow gun.
2. New piston, no washers: I first used the pneumatic blow gun as a pilot valve and it just wouldn't engage which was irritating to say the least so I tried a 3/4" ball valve and it worked first time but not the second time due to the rubber ripping off the bolt.
3. New piston, Washers: It worked first time and every time after that so good in fact that I had to try some type of projectile. Said and done I put in a light plastic "screw plug" (I hope this is the correct word) and some plastic from a bag to seal it in. Seeing as I was in my basement I didn't want to shoot a heavy potato damaging something and I thought this wouldn't cause any damage.
I pressurized the tank to a mere 60 psi and fired in to the laundry room... shooting a hole straight trough the laundry bag/basket, needless to say I didn't expect that.
That's just the test fires, I have tried pressurizing the air tank a LOT of times until I found the correct glue that would let me open the plug after it dried so I could switch out pistons. This is probably what has taken the longest time since the glue has to dry for a couple of days in between testing it. The first glue really was hit or miss, it only worked a couple of times and usually failed after a couple of test fires but at least I have found a glue that works good now.
With a working piston I tried fixing the problem with the pneumatic air gun not letting enough air through by drilling out most of the holes and making some new holes:
[img]http://i102.photobucket.com/albums/m117/nismo299/pneumatic_gun_mod.png[/img]
Sadly it didn't really work 100% It works a lot better but it is taking a couple of seconds to engage the piston which steals a lot of pressure better used for firing the potato.
I will probably try to modify it a bit more and if that doesn't work I'll have to start looking for alternatives.
I have also added some o-rings to the barrel and bolt to stop air from escaping between the barrel/bolt/cartridge. At first I was kinda skeptic to this and thought it would make the bolt and barrel painfully slow and ruining the cycling, turns out enough lube solved that problem. Don't get me wrong it is "harder" to move the bolt but not by much and it still feels smooth.
The groove cut using a hacksaw blade screwed on a piece of wood and then turning the pipe slowly making a perfect groove:
[img]http://i102.photobucket.com/albums/m117/nismo299/oring1.png[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/oring2.png[/img]
I did this to both the bolt and the barrel theoretically making no air escape at all when fired:
[img]http://i102.photobucket.com/albums/m117/nismo299/oring3.png[/img]
This is where the barrel and bolt is placed when in the firing position except inside the gun of course:
[img]http://i102.photobucket.com/albums/m117/nismo299/oring4.png[/img]
Last but not least I tried firing a potato from just the air tank in this stupid test setup:
[img]http://i102.photobucket.com/albums/m117/nismo299/test_setup1.png[/img]
Video; I didn't actually try to hit the vent and yet again I wasn't really expecting it to bend a metal vent but oh well it did bend back ok :buddy:
90 PSI
[media]http://www.youtube.com/watch?v=Y7cCltE-uP8[/media]
This is progress from the past weeks and not just from today. What do you think, should I do more smaller updates whenever I do the things that I do or should I keep on making larger updates?
Moar videos :D
Sorry for revive, but that cycling is sexy.
I really hope that you continue work with that.
Thread revival time!
What has happened?
Well, I joined the air tank to the rifle and no it didn't take this long, I just couldn't figure out a way to get my pilot valve to open quick enough and I just kinda felt like not doing anything with it for a long time but I finally caved in and bought a quick exhaust valve so now it is: My homemade valve > quick exhaust valve > blow gun pilot valve, probably overkill but now it works great.
Now for what you probably came to see, Videos.
Test firing a AAA battery with 75psi, I didn't feel like recharging the compressor again but I'll try to make another video with higher pressure soon (Valve time):
[media]http://www.youtube.com/watch?v=49eDS8Pxclo[/media]
Some pictures:
[img]http://i102.photobucket.com/albums/m117/nismo299/rifle.jpg[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/hit1.jpg[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/hit2.jpg[/img]
[img]http://i102.photobucket.com/albums/m117/nismo299/hit3.jpg[/img]
Yeah I will clean it up and get som nicer pressure gauges and stuff in time but for now this is all I got.
Oh my god, that would be the coolest weapon ever - an air controlled pistol that shoots BATTERIES. Hell, I'd even do it potato-gun style with hairspray or something in the back and a sparker from a grill.
I guess I'll get to work
if i had this gun, i'd finally have a use for all the dead batteries lying around my house.
So finally we know what to do with old batteries instead of saving them up in a chemical box for years.
Nice work man. I would love to make something like this.
Yo how long did you make the 50mm ABS pipe? And does the barrel have to be as long as you made it?
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