Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 42 users online :: 3 registered, 0 hidden and 39 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Marble loading design

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Marble loading design

Unread postAuthor: HoppinS10 » Tue Nov 23, 2010 8:03 pm

So I am currently working on a QEV cannon and while I wait for my 3-way valve to arrive I decided I would start working on a breech loading design. Hopefully I am posting this in the correct section. Anyways here are some pictures of what I have made. I know some of the parts are a little sloppy at the moment but it only took me about 5 minutes to make what I have. I am looking for advice so any tips or constructive criticism are greatly appreciated.

I still need to drill a hole on one of the end caps (pipe reducers) so a shaft can be attached to the "bolt?" so it can be moved back and fourth.

Here is a link with pictures to my QEV cannon
http://www.spudfiles.com/forums/qev-triggering-help-t21984.html


<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191330.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191330.jpg" border="0" alt="Photobucket"></a>
Here is just a piece of 1/2 inch pvc to use as a "mock" barrel

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191340.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191340.jpg" border="0" alt="Photobucket"></a>
A 1/2 coupling which I have sanded down the inside so it will slide on the barrel. Also a hole was drilled into it to allow a marble to fit through.

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191353.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191353.jpg" border="0" alt="Photobucket"></a>
A couple of 1 inch to 1/2 inch adapters which have been cut down so the bolt will have room to slide when it is put together.

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191401.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191401.jpg" border="0" alt="Photobucket"></a>
Just an unmodified 1 inch to 1/2 inch tee

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191433.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191433.jpg" border="0" alt="Photobucket"></a>
Bolt placed on the barrel with holes aligned (sorry about the flash)

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191458.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191458.jpg" border="0" alt="Photobucket"></a>
Bolt on barrel with the barrel hole covered

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191530.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191530.jpg" border="0" alt="Photobucket"></a>
Assembled

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191546.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191546.jpg" border="0" alt="Photobucket"></a>
Closeup of the bolt closed

<a href="http://s1106.photobucket.com/albums/h379/hoppins10/?action=view&amp;current=IMG_20101123_191623.jpg" target="_blank"><img src="http://i1106.photobucket.com/albums/h379/hoppins10/IMG_20101123_191623.jpg" border="0" alt="Photobucket"></a>
Closeup of bolt open
  • 0


HoppinS10
Private
Private
 
Posts: 17
Joined: Wed Nov 17, 2010 6:06 pm
Reputation: 0

Unread postAuthor: mlz3000 » Tue Nov 23, 2010 10:10 pm

That's a pretty clean looking breech.

Are you planning on using a magazine with it? It looks like it could take one without any modification.
  • 0

User avatar
mlz3000
Corporal
Corporal
 
Posts: 69
Joined: Sat Oct 23, 2010 4:55 pm
Reputation: 0

Unread postAuthor: HoppinS10 » Tue Nov 23, 2010 10:34 pm

Yeah I plan on just putting a piece of 1/2 inch PVC into the top of the tee
  • 0


HoppinS10
Private
Private
 
Posts: 17
Joined: Wed Nov 17, 2010 6:06 pm
Reputation: 0

Unread postAuthor: Gaderelguitarist » Tue Nov 23, 2010 10:39 pm

Back in the day, I built something very similar to this with a sliding cover bolt. I used a spring to ensure that it was closed when I wasn't pushing it back. Of course MINE failed miserably as I was young and stupid. That aside, this looks well built.

mlz3000, I think the breech is designed for use with a magazine, considering he bothered with a tee fitting instead of just a stand-alone slide.
  • 0

so many muchness
User avatar
Gaderelguitarist
Colonel
Colonel
 
Posts: 580
Joined: Sat Aug 16, 2008 9:56 pm
Location: Columbia, MD
Reputation: 0

Unread postAuthor: mlz3000 » Tue Nov 23, 2010 10:45 pm

I figured, but he didn't mention it.

Also, I misunderstood the design a bit :oops:. I thought that he had the tee there to facilitate a twist-only open method, rather than having to move it back and forth on the barrel.
  • 0

User avatar
mlz3000
Corporal
Corporal
 
Posts: 69
Joined: Sat Oct 23, 2010 4:55 pm
Reputation: 0

Unread postAuthor: Selador » Wed Nov 24, 2010 2:37 pm

Please forgive the sidetrack here...

Where are youse guys getting marbles that fit a 1/2" sch40 PVC pipe ?

I looked all over town for marbles. The only places I found them was at a craft store, for a gawdawful amount of dineros. And at a dollar store. Pretty good bargain there.

But the bargain went out the window when I got home.

The marbles are too big.

WT Huh ???

~~~

Edit to add to HoppinS10...

I am wondering why you didn't just use a 1/2" tee, in the first place ?

Hog it out to slide on your barrel, just like you did the original 1/2" fitting, and viola', you have the complete bolt in one swell foop.
  • 0

If you can't fix it, you don't own it.

Selador
2nd Lieutenant
2nd Lieutenant
 
Posts: 213
Joined: Wed Nov 03, 2010 9:44 pm
Reputation: 0

Unread postAuthor: Gaderelguitarist » Wed Nov 24, 2010 2:47 pm

Where are youse guys getting marbles that fit a 1/2" sch40 PVC pipe


Generally, you have to buy a bulk supply and then sieve them with a chunk of barrel material. Personally, I would just go to Mcmaster-carr and buy some steel balls. They seem to be a pretty consistent size.

Edit:

swell foop


Me oh my, that is one swell foop you have there.
  • 0

so many muchness
User avatar
Gaderelguitarist
Colonel
Colonel
 
Posts: 580
Joined: Sat Aug 16, 2008 9:56 pm
Location: Columbia, MD
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: HoppinS10 » Wed Nov 24, 2010 6:02 pm

Where are youse guys getting marbles that fit a 1/2" sch40 PVC pipe ?


I bought mine from a store called hobby lobby. They have all sorts of arts and crafts stuff they come in bags of about 100 for $2. Although they dont fit perfect in the barrel they are pretty close and work well. My cannon will fire through 1/2 inch pine at about 100 psi. They are pretty consistant in size from what I have seen so far. Im sure those steel balls that McMaster sells would be a better bet but the marbles were cheap and i can buy them locally.

I am wondering why you didn't just use a 1/2" tee, in the first place ?

Hog it out to slide on your barrel, just like you did the original 1/2" fitting, and viola', you have the complete bolt in one swell foop.


I was originally looking at using just a tee but didnt find it reliable enough to load 1 and only 1 marble into the barrel each time the trigger is pulled. I know there are some people who have built cannons with a "flap" in the tee that blows up to prevent a second marble from falling into the barrel but there is still some air that goes up into the magazine which would hinder performance. Also if I decided to make a sliding tee the magazine would move with the tee as it slid to open and close the breech. Hopefully I am making sense it has been a long day at work and my brain is fried.



Also forgot to mention that I have a spring loaded air cylinder that I plan to use to actuate the bolt. If all goes well when the trigger on the 3 way valve is pressed the gun will fire and also release the air from the cylinder which will bring the bolt into the open position so a marble will fall into the barrel. When the trigger is released, the cylinder will be pressurized and slide forward which will close the breach ready for the next shot. This is all in my head and havent actually attempted to make it work yet.
  • 0


HoppinS10
Private
Private
 
Posts: 17
Joined: Wed Nov 17, 2010 6:06 pm
Reputation: 0

Unread postAuthor: mlz3000 » Wed Nov 24, 2010 8:18 pm

That sounds awesome! :shock:

You'll have to make sure that the breech stays open for long enough, or the marble might not fall in, but that sounds like a sweet design.
  • 0

User avatar
mlz3000
Corporal
Corporal
 
Posts: 69
Joined: Sat Oct 23, 2010 4:55 pm
Reputation: 0

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'