Air Gun Home :: View topic - Project Spearchucker Spring powered arrow thrower

ZipSnipe · Veteran Member

Hey all, I figured you guys might be interested in this project I started. I started looking at pistol crossbow as a home defense gun( yes I know I should just buy a shotgun) anyway I got a lil rugrat that I would have to worry about and figured a crossbow would be kool. But then I found out its not good to leave the crossbow strung up, I had the trigger mechanism all made up and decided on making a spear gun powered by a powerful mold spring(mold springs are used in the tool and die industry on plastic injection molds , extremely powerful).

So here's a pic so far

Uploaded with ImageShack.us

More to come if your interested!!!! Got pics of the trigger set up too if ya want

radar · Silver Status Member

Cool. When I was in my mispent youth, I was always doing stuff like that...but not that pretty...so I have a soft spot for rowdy projects like yours. As for home defence, I would still stick to the shotgun idea and lock it properly but accessibly. A kid could get a hold of anything loaded, including a speargun, and have a problem.

ZipSnipe · Veteran Member

The only problem is my misspent youth has carried over into my 40's.

I am just one of those guys just kinda of scared to have a firearm in the house but I do have a great appreciation for them and if SHTF I will have one in my possession.

Besides if some unlucky bastard broke into our bedroom the wife will be pelting him with Umerex Steel Storm full auto and I will do the kill shot with Spear Chucker. Works for me!!!

But for now this is a fun and hobby project for me.

If ya look close , you will see an aluminum pipe that runs thru the stock. That has been replaced with a steel pipe which is thicker and stronger to house the mold spring that is on order.

more to come....

radar · Silver Status Member

I never thoght of a steel spring. I suppose the projectile would have to be fairly heavy to take advantage of it? I used rubber strips like a regular underwater speargun. I was going to duplicate the mechanism and make it into a 2 shot double barrel, but never got around to it.

donec · Senior Member

When you get it done how about posting a break down so maybe some of us can make one?

ZipSnipe · Veteran Member

Sure donec

Here.s how I started, I made a trigger mock up on some scrap wood and using nails and some black teflon plastic I had laying around.

Uploaded with ImageShack.us

From the mock up I went to this housing using 1" aluminum, 1/4" teflon and steel

Once the trigger was made up and its housing, I laminated 2 1" red oak planks , bandsawed them and using a rasp file(a must if your doing pistol grips in wood) and got it looking like this

Uploaded with ImageShack.us

The trigger if ya look close , you see I use 2 springs and really could have used just one. I also will be taking out more aluminum after I figure the safety mechanism in.

radar · Silver Status Member

Beautiful workmanship, dude. Cool

donec · Senior Member

Thanks ZipSnipe nice work, but just looking at the trigger it looks like everything is so close that it may not have enough clearance. Also I see no way to cock it. Or am I getting ahead of the project?

ZipSnipe · Veteran Member

Ya know it figures while I have spent about $26 on springs that I would find a powerful spring in the dumpster.

I also have a problem with my design

See the dark blue part of the pic, that part hooks into the trigger nut. Now my thought was it would end up being 4-6 inches long. But in reality it is 12" long. When I release the trigger this 12" part is flying along and it concerns me that it could break apart and go flying.

Now when my new spring comes in which I think it will be Monday, I am hoping that I will be able to cock it back more but I am thinking the dumpster spring might be the better candidate. It has less coils and is just as powerful as the mold springs. Less coils means I can pull it back further and maybe get the dark blue part down to 6-8".

Then again I might need to scrap the spring powered idea and convert it to crossbow. BTW I designed this so that if the springs didn't work good I could easily convert it to a recurve crossbow.

ZipSnipe · Veteran Member

Yeah donec if you look at the Paint pic of the firing mechanism. The dark blue part was initially going to cock it when it pulled back.

But I figured a better way was to have a rod inside the firing spring so that when it is pulled back it cocks the trigger.

radar · Silver Status Member

Or put the bolt in a 3/8" barrel with the fletching replaced by a compressable mop type stabilizer (like airgun darts) and convert it to a spring-piston airgun? It would be some work, but the velocity potential would go pretty high, I think. Also maybe consider rubber band propulsion?

-Rob

ZipSnipe · Veteran Member

Yeah I thought about the piston deal, I really need to research how the airguns that use pistons work.

But since I am this far into the project, I figured I would go ahead and try it the way I have it designed.

As long as the spring on the cocking handle can slow the firing spring mechanism down or absorb the impact then it will be ok, but if it can't then the project will be on hold.

radar · Silver Status Member

That makes sense.
Can you further split the cocking handle so it only leaves the minimum amount of mass at the front of the cocked power spring, and the rest slides forward to rest out of the way?

ZipSnipe · Veteran Member

Yeah that dark blue part of the trigger needs a total re design, it will not work.

For one the arrows that I ordered (which the Post Office might have lost) have the fletching on them and thats a problem for the blue part.

But the main part is that its a large part that is going to see some serious stress.

In fact the more I look at this part of the gun the more I realize it can't be done unless I make a whole new stock for it and rebuild the trigger and use bigger rails.

In fact I am going to shelve it for now and work on getting the Crosman 1077 and do a tactical mod for it.

Sometimes ya just gotta admit your licked......

robert w · Senior Member

i belive your on to something good there now just work the bugs out and BOOM your on the map. great work there