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well I asked a question a while back....under the topic heading Method of venting the pilot, anyhow I have an update on the progress....
I asked about if I should switch to a spring loaded ball valve as the pilot exaust instead of the modified blow gun, and was told to first concentrate on lowering pilot volume and using a better piston (seal wise). Well, what I ended up deciding on was doing everything, I cast a piston from epoxy and then lightly sanded it to fit perfect, and made another modified grease zerk for it. then I redirected the ball valve so the exaust wouldn't shoot
you in the eye when you shoot it, wich also had to do with a good angle for the spring to pull the valve, I straightened the valve handle for a more direct pull, and sanded some cork down until it was a press fit inside the pilot areas. Then I drilled a hole through the center of all the cork. So... my pilot volume is way way down, the piston seals really well, and I'm going to have a much lighter trigger pull once I figure out how to design my trigger and sear mechanism. Woo hoo, I'm having fun with this little project.
Oh yeah, I also found a schrader with 1/4 inch pipe thread..
I screwed it into a female quick connect, so I can put it on the back if I want to use a shock valve or a home made pump I'm kinda in the planning stages on.
Oh yeah, I also added a pressure gage, wich doubles as a cheek rest when sighting in on something (it's at a slight angle).
hav'n a good time over here, Lock
Last edited by lockmanslammin on Fri Sep 26, 2014 11:26 am, edited 7 times in total.
If you're not using o-rings the zerk was unnecessary, otherwise it's great to see this project evolve
well, it doesn't have o rings, but it is really a very good seal for just being a slide fit, also I just thought the zerk was a fun edition, and fun to make...hehe.
That is a beautiful piece of work lock, i am glad to hear you are having so much fun building these works of wonder.
If it were my cannon i would stick to the current pilot method, however a blowgun will provide a more stable platform for accurate shots.Well done Lockie. 10/10
America, the greatest gangster of all time. With 200 million odd foot soldiers at it's whim and call.
When you fill your car with refined oil remember that it has been paid for with blood and guts, some from your own countrymen, most not.
and you will notice jsr that I missed my feet and beer belly with the camera this time...hehehe.
So I'm in the planning stages of the trigger and sear assembly, its going to have two sheets of something with pivot points for the levers and rods that make it up, but I'm kinda torn as to whether to go with 1/4 inch plexi so all the works will be visible or aluminum or something like that for a clean look....ahh decisions decisions.
Duly noted and appreciated
A few pics of progress on the Trigger and sear assembly. The first pic is just to show where the parts are located on the cannon...
This next pic is a close up of one side of the frame with a rough sketch in dry erase marker of how I plan to make it. its kind of hard to see due to the reflections, but the trigger is laying where it will be inside the assembly the bottom hole will be the pivot for the trigger, the next hole up will have a small extension spring attached and the top hole will be where the linkage rod connects.
The next pic is perty obvious, I just like how it turned out so I took a close up.
if any one has any questions or comments shoot away.
Last edited by lockmanslammin on Fri Sep 26, 2014 11:37 am, edited 1 time in total.
This isn't the gun itself but the way I will be powering it to its potential.
It's the beginings of a stirrup pump I'm making for it. It will be 3/4" cylinder, with 1/2" allthread for the shaft (thick for the stiffness as it will require around 150lbs of force to get around 400 psi). The epoxy is a two part putty that works like clay once mixed. The pex tubing will be heated and slid over the all thread so it slides smoothly through the reducer. it fits a little tight right now, so I will be sanding the pex and the inside of the 1/2" portion of the reducer until it slides easily. I already have a home made check valve made from brass parts and a ball bearing, spring and o-ring. I will post pictures of the check valve once it has proven it's reliability. Also I've included two pics of a peep rear sight my friend donated to the cause. It's adjustable for windage and elevation, and will be a cool addition, as I was intending on iron sights from the begining, because I like how closely coupled to the barrel iron sights are. Here are the pics.
any questions or comments?
Last edited by lockmanslammin on Fri Sep 26, 2014 6:30 pm, edited 1 time in total.
Coming along nicely, a spring loaded trigger will be of great assitance to consistent triggering and consequently accuracy, so you'll be needing those sights
alright, the pump is working...wooohoooo
First three pics are the bottom assembly and how it is filled with resin and has pilot holes drilled through it to keep the dead air space down. the device opposite the gage is a homemade ball and spring check valve, and it is working perfectly.
alright then, the next pic is the floating oring piston assembly all finished. It doesn't look like there is a gap there, but there is. under the ring there is a hole drilled through the allthread, and there is another hole drilled from the end of the allthread up to the cross bore hole for the valve to work. opposite the oring sealing face is a 1/2" nut that has been cut in half and turned down on the "poor mans lathe", a bolt for a mandrel and running the drill opposite the grinder and grinding it down. Then there is epoxy to hold it in place. Accually the epoxy ended up just acting like a nut extension as it turned off the allthread right along with the bolt, so I used some real thin CA and locked it in place. Here's the pic.
Next pic is the handle, I have access to a TIG welder at work, so I took a short piece of schedule 40 stainless pipe and welded a 1/2" nut to the side of it. Then I drilled and threaded the pipe face that it is welded to, so the allthread would have a better connection. Then a nut to lock it in place.
The last two pics are the top of the pump, and the gage after 57 pumps, starting from 0 PSI. The allthread has been sleeved with PEX tubing and sanded down to slide nicely in the compression reducer. Stuff was a pain to get on the allthread. I had to heat it over the stove and slowly work it down the threads.
Any questions or comments?...
Edit: I thought I should add a pic of the pump attached to the cannon.
It uses a quick connect. Weird perspective going on here, the cannon is accually longer than the pump.
Last edited by lockmanslammin on Sun Oct 05, 2014 10:31 am, edited 1 time in total.
I can't help but think that your chamber is way larger than it needs to be.
I am of the small chamber high pressure school. You could reduce the chamber drastically and get to higher pressure with much fewer strokes of the pump.
Larger chambers give a nice bang but the projectile is long gone by the time all the air escapes.
I hear you on the chamber size. I know it is way to big, but when I was building it, I liked the way it looked, and I wanted to have a good support up front incase I decided to add a breech loader.
On a different note, I just fired a foam ear plug with a 177 pellet poked inside of it through 3 mountain dew cans. It put a healthy hole through both sides of all three and then shot the piece of 3/4"x 4"x 6" uhmw plastic, that I was using as a back stop, across the room and into the wall about 17 feet away and got me yelled at by my fiance. The shot was fired at 270PSI.
I can't wait to fire some 54 caliber lead balls at 3 or 400PSI and see what kind of carnage it will do. There are some 2x4's in the garage that are IN for it tomorrow night..<evil> hehehehehehe.
Another thing I was wondering....
Is this thread bothering people? Are established members thinking that I am taking up way to much space? Should I be putting this thread in the "how-to database"? Just seems like there hasn't been much response to the postings. I know when I first started reading posts here I really enjoyed the ones with pics and info. Or am I so lucky as to be doing enough things right that people don't feel the need to post? I hope thats the case. Any how, I will still be updating this thread with the trigger mechanism as I get to it next week.
happy spudding everyone,
Not at all, we love seeing people's well illustrated progress here, don't stop sharing
Is it just my expectations were too high or would you guys expect more from a 1/2" glass marble @ 275PSI. This is a chunk of 2x4 by the way, shot from about 15 feet away. I hope one of my 54 calibre lead balls does better. The blue you see in there is part of the greased t-shirt patch I used.
Last edited by lockmanslammin on Fri Sep 26, 2014 6:48 pm, edited 1 time in total.
That seems like perfectly reasonable performance to me at 275 psi, if you want to go deeper just up the pressure
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