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Spring Pistol Trigger Issue

Posted: Wed Dec 23, 2009 4:48 am
by skinner
G'day all.

Its been a while since ive been on here with work and everything, anyway.

I've got a new project 99% finished. Its all been machined as good as I could get it. I'll out up some photos as soon as I can. Looks pretty menacing as its been made out of steel that's been machined and laser cut.

Anyway, onto the topic. Im having a little issue with the trigger and it seating on to "sear" so to speak.

The trigger and the seating face (thats what im calling it) make contact and are flush to each other. But when I go to relieve the cocking plunger, the trigger seems to just slide off as it should when its being fired.

I came up with a few ideas, I'll demonstrate in some following pictures.

Any help would be awesome.

Cheers.
Skinner

Posted: Wed Dec 23, 2009 5:00 am
by skinner
This image shows what it is meant to look like when its been cocked and ready to fire.

The issue I have is that the triggering sequence (of pulling the trigger down: rotating it on its pivot, hence releasing the piston and spring).

PS: Sorry to double post, Im making pictures and posting them as I go.

Posted: Wed Dec 23, 2009 5:05 am
by skinner
This is one idea. Machine a very deep inner taper. I may not even have to manipulate the trigger at all, just allow it to rotate more.

any help would be fantastic.

PS: Sorry for the Triple post.

Posted: Wed Dec 23, 2009 5:33 am
by airheadnoob
WHOA you machined it all. i wish i had those tools :(

cant wait for damage pic

needs a handle tho. fix the welds up too:D
i like it , it looks like a metallic nerf gun :D id bet it would sting if you used nerfs

Posted: Wed Dec 23, 2009 5:40 am
by skinner
I have access to a lathe, mill and laser at work so I thought I might sneak in a foreigner just before we finish work for the year.

It fires pretty good. A 6mm BB saboted in a plastic bag is good enough to enter a can at close range. Im not expecting "real" air rifle power. Just something to play around with.

About the welds, I was in a rush. I lined it all up perfectly and realised that a few moderately sized tacks were good enough to hold it. Eventually I will TIG it all up and make it look schweet.

Cheers.

Posted: Wed Dec 23, 2009 6:07 am
by qwerty
I think the other spring is to powerful to hold the main spring/piston in place.
try roughing up where the trigger meets the piston and it should have more grip. Another tip, don't you think the plunger would be a bit heavy and would lose performance?

Posted: Wed Dec 23, 2009 6:23 am
by skinner
The piston spring is pretty powerful, Ive looked at the avenue of a stronger trigger retaining spring, just gotta get one and see what happens, this may result in the trigger being to hard to pull.

I had a thought about knurling the trigger area and decided it wouldnt be a good idea as the second stage of the piston (the seat face) has to go through the chamber bore and if it is damaged then it may gouge out the bore and ruin the pistols inner bore.

Im not sure if the heavier piston will reduce performance. Its made from silver steel so it would be pretty hard wearing. I like it being heavier, the force thats generated behind it seems to give it a nice kick.

Posted: Wed Dec 23, 2009 9:55 am
by Gippeto
It's a problem of geometry. The force point should be before the pivot point.

Image

You have two choices that I see...redesign, or play with springs. In your shoes, and because it's just for "playing with" I would try some other springs.

Posted: Wed Dec 23, 2009 10:21 am
by qwerty
You could try attaching a thin bit of rubber to the trigget catch.

Posted: Wed Dec 23, 2009 2:17 pm
by psycix
Move the pivot point forward and as far up as possible.

Posted: Wed Dec 23, 2009 7:12 pm
by skinner
I see what your saying Gippeto, I have my trigger system the wrong way around. the pivot needs to be in front of the trigger point, That would require some kind of 2 piece trigger. I could do that, it would just take a whole lot of redesigning, I could play with the strength of the trigger spring to see if that has any effect. I dont think it will but its worth a shot.

I think I will try to put a deep taper on the seating face. Only needs to be something small like 0.5 of a degree.

Thanks for all your help.

Posted: Wed Dec 23, 2009 10:59 pm
by maverik94
needs a handle tho. fix the welds up too:D
It HAS a handle, I assume you mean it needs a grip. Anyway, that looks like one ass-kickin' gun. I doubt it will be super-powerful, but it looks perfectly functional and pretty beautiful too! Anyway, make sure you post it in the showcase section when you are completely finnished. By the way, are you planning to paint it? If I were you I wouldn't, I think it looks pretty bad-ass with just the plain steel body, anyway, cheers! it's not every day we get such a nice looking gun, or a good functioning springer for that matter.

Posted: Wed Dec 23, 2009 11:26 pm
by skinner
Thanks Maverik94, Its not uber-powerful, but thats not what I was looking for. All I wanted was a self-sustained pistol, nothing that required a pump. and besides, this project was only an experiment.

I'll be sure to post it in the showcase when its fully done. Im not planning to paint it, I was going to go with a wood grain grip and clear gloss it, just to make it look like a regular gun, Or another idea I had was to engrave the chamber and barrel with tribal styling (if anyone has ever played CoD: Waw, once you pack-a-punch a gun) Once Ive sorted out the trigger issue, in which shouldnt be too hard to solve, Ive got a few ideas that will work. I will make a post with all details on how I made it and everything.

Fires 10mm long bits of 6mm round bar pretty well.

Cheers.

Posted: Fri Dec 25, 2009 5:44 am
by skinner
I was thinking today while eating Christmas lunch.

If I were to increase the load created by the trigger retaining spring, and maybe get a less powerful spring for powering the gun but with a higher spring rate, maybe the gun will cock, Im not sure if it will, But I guess time will tell.

Although, a redesign might be called for. Anyone have any ideas on how I should go about this?

Cheers.
Skinner

Posted: Thu Dec 31, 2009 1:28 am
by skinner
Update: 31/12/09

G'day all.
I've had a little luck with installing a shorter, stronger trigger spring. It allows it to lock on to the catch face and allow the gun to be cocked and fired by means of the trigger.

But this is at the expense of power (at the moment) as I use red postal rubber bands. It still fires a 6mm saboted BB around 50 foot. its pretty cool.
Until I get back to work and have access to the lathe again I dont think I will be able to use my original spring until I taper the catch face to allow more positive contact.

Cheers.
Skinner