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Discussion Starter · #1 ·
This is kinda crude and I'm capable of better, but here it is.
Sorry for the lack of back-side pix. Maybe later.
This is all of it, there is no "barrel" or "Y", yet.
The back end of this piece of wood has a buttstock shape.
The notch in the wood was a previous attempt at this.
Hope to finish it soon.

This lock plate is mounted on the leftside. It's attached by the four corner spacers with screws that go through the wood. (just a piece of a pallet).
The small loop at the left is for the remote trigger. The sear (on the plate's backside) rotates counter-clockwise from a pivot at the bottom of the plate.
This lock plate is removable and can be attached to other wood or whatever.
This is my first attempt to create any kind of trigger mechanism, fun.


Here is a top view, showing the four corner spacer mounting screws.
Also, the sear return spring.


Here I'm trying to pull the sear forward and take a picture at the same time. Kinda like walking and chewing gum.
Shows the lock open with sear forward.


Paul in Oregon
Hope this is in the correct forum area, sorry if it isn't.
 

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That's splendid. Yours is the first mechanism that I've seen that has a return mechanism. The others mostly rely on multi-step hand setting.

I'm not 100% sure I understand the mechanism, but I think the pouch grip pins are held closed by the shear bolt on a shear plate and the shear plate is held in the closed position by the return spring, but there is a lever directly connected to the shear plate that can be pulled by a trigger (not shown) . When the lever is moved, it opens the shear gate releasing the grip pins, one of which then moves out of the way releasing the pouch.

I look forward to seeing it in action, but for now I have three comments:

  1. While I like the simplicity of having a single moving pouch grip pin, I worry that it would make the pouch jump and put spin on the shot or give it an unusual trajectory. I suppose this wouldn't be an issue in your design, which is vertically oriented.
  2. I wonder if this mechanism might slip if the band force is too great. The draw would be translated into torque at the grip pin lever and that would seem to want to rotate the shear plate. If that happens, you might consider mounting the moving grip pin lever a little higher in the bracket and shooting the thing backwards to the direction most people do it. Doing so would give some mechanical let -off to the shear mechanism.
  3. How is the release action? I prefer a sudden release.
Below is a picture of the mechanism I've been using. It's not directly relevant to your pouch grip pin arrangement, but it illustrates what I mean by something that gives a linear release path; is rock solid until firing with band force helping to stabilise the lock-up; and has a sudden and smooth release.

 

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Here's a photo of the simple 2 arm trigger mechanism.

Although there is no automatic trigger setting, when you have the pouch in hand, it is trivial to close the arms and lower the trigger in a single motion.

Easy peasy, cheap, no metal cutting, and best of all, it works great.

I strongly suggest that you consider a fixed fork and a movable ratcheting trigger.

It is much easier to draw towards you with 2 arms than away from you with one.

When I draw the trigger mechanism towards me, my hands are on the hinged 'sear' holding it down for safety.

Joerg has shown us a very straightforward way to make a strong, safe trigger out of wood, why work so hard to cut steel?

 

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Whatever you do, I'd love to see you complete it and shoot it. We all have opinions and suggestions, but if yours is safe to shoot, it's as good as it needs be.

FWIW, I strongly favour metal mechanisms too. The action has the potential to be made slicker and stronger in steel.

I have had these things as a lingering obsession since I was 12 and saw a Japanese shingshot on a stock advertised in the back of an airgun catalogue. Every few years something triggers it again and the obsession rears up in a big way.

To me regular slingshots are just a portable version of the slinging rifle. That's why I spend so much time thinking about bands. I've tried pulleys and single bands and multiple bands and levers. I've made many prototypes and entertained more crazy ideas than I'd admit to or care to describe. In the end there's no best way and all that counts is you built it.
 

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Whatever you do, I'd love to see you complete it and shoot it. We all have opinions and suggestions, but if yours is safe to shoot, it's as good as it needs be.

FWIW, I strongly favour metal mechanisms too. The action has the potential to be made slicker and stronger in steel.

I have had these things as a lingering obsession since I was 12 and saw a Japanese shingshot on a stock advertised in the back of an airgun catalogue. Every few years something triggers it again and the obsession rears up in a big way.

To me regular slingshots are just a portable version of the slinging rifle. That's why I spend so much time thinking about bands. I've tried pulleys and single bands and multiple bands and levers. I've made many prototypes and entertained more crazy ideas than I'd admit to or care to describe. In the end there's no best way and all that counts is you built it.
Stronger in steel?

Steel vs rubber and leather; compared to wood, seems like overkill to me.

If wood is 100 times stronger than rubber/leather do we need steel that is 10,000 times stronger?

In addition, a tree fork slingshot is not in the same universe as using a steel mechanism.
 

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Steel has more potential. Steel is stronger and more wear resistant and more polishable, so it is possible to make a mechanism smaller, with less travel and a slicker action. That's why pistol's hammer mechanisms, crossbow nuts and other applications are made of steel not plywood. Wood will suffice for this application if one is not set up for working steel, but a steel mechanism can be made better. Even pine or basswood would probably work if you were willing to make it bigger and have more travel. My intention is not to say your mechanism is too weak, but to say I fully respect and understand Paul's choice of material.
 

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OK, this is short, I'll try and upload exploded and rear pix tomorrow (sorry, wifey's date night).
Remember, this is just a prototype (A-Phase for you ex-tek's).

Metal:
All aluminum, 1/8" plate, like hardware store stuff. A bit too soft for me.
I really want it to be steel, that's for later.

The shear pin (sear) and it's pivot put the pin past center of the pouch grippers (over-center).
I was afraid that it would release itself, kinda like a revolver hammer pushing the trigger back, not good.
I worked on it until I could not get it to move at all (anything). Initially it did want to push the shear plate back, but not now.

I picked up a Harbor Freight 48" clamp today. Started disassembling it.
Now I'm torn between using a fixed fork or a moveable fork.
I want to be able to use this lock plate, so I may go with a moveable fork for the first try.
I can make sure that the design allows changes (in other words, don't do too much permanent, yet).

Personally, I did not expect any comments at all, Thanks!

Other pix here (PDF just added): Lock_Plate


Paul in Oregon.
 

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I've never had a problem with that. I pinch the ball as I draw the bands and by the time I hook on, there's so much side force on the pouch from tension alone that it's very secure. Try it yourself. Loop some string at the back of the pouch, stick a ball in it and draw it back.
 

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OK, this is short, I'll try and upload exploded and rear pix tomorrow (sorry, wifey's date night).
Remember, this is just a prototype (A-Phase for you ex-tek's).

Metal:
All aluminum, 1/8" plate, like hardware store stuff. A bit too soft for me.
I really want it to be steel, that's for later.

The shear pin (sear) and it's pivot put the pin past center of the pouch grippers (over-center).
I was afraid that it would release itself, kinda like a revolver hammer pushing the trigger back, not good.
I worked on it until I could not get it to move at all (anything). Initially it did want to push the shear plate back, but not now.

I picked up a Harbor Freight 48" clamp today. Started disassembling it.
Now I'm torn between using a fixed fork or a moveable fork.
I want to be able to use this lock plate, so I may go with a moveable fork for the first try.
I can make sure that the design allows changes (in other words, don't do too much permanent, yet).

Personally, I did not expect any comments at all, Thanks!

Other pix here (PDF just added): Lock_Plate


Paul in Oregon.
Using the Harbor Freight clamp you can configure it both ways, fixed or movable fork, fixed or movable trigger.

Try both and see which is best for you.

Are you disappointed that it is an aluminum clamp and not a steel clamp?
 

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Discussion Starter · #12 ·
Using the Harbor Freight clamp you can configure it both ways, fixed or movable fork, fixed or movable trigger.

Try both and see which is best for you.
Are you disappointed that it is an aluminum clamp and not a steel clamp?
Not really, it was expected.

Good, thanks for the info. Almost makes me wish I'd purchased two, for the two ratchets.

Paul in Oregon
 

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Very nice design! You ought to see if you can make it so that both of the pins move evenly. I would think that would allow for more accuracy.
 

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Discussion Starter · #16 ·
Very nice design! You ought to see if you can make it so that both of the pins move evenly. I would think that would allow for more accuracy.
Well, Aaron, thanks for the kind words.

Actually, one of the lock pins does not move at all. (the lock pins are the ones with the gold colored screws)

Paul in Oregon
 

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Discussion Starter · #17 ·
Here's a photo of the simple 2 arm trigger mechanism.

Although there is no automatic trigger setting, when you have the pouch in hand, it is trivial to close the arms and lower the trigger in a single motion.

Easy peasy, cheap, no metal cutting, and best of all, it works great.

I strongly suggest that you consider a fixed fork and a movable ratcheting trigger.

It is much easier to draw towards you with 2 arms than away from you with one.

When I draw the trigger mechanism towards me, my hands are on the hinged 'sear' holding it down for safety.

Joerg has shown us a very straightforward way to make a strong, safe trigger out of wood, why work so hard to cut steel?


[/quote]

Stu,
I have the forward plate mounted on the clamp frame, for the fixed "Y".
I put a piece of wood inside of the bar and screwed a platform on top of that.

Then I took apart the screw mechanism (the clamp parts) and used both sliding blue pieces to mount the lock plate, the kind with two swing arms.
Now to make a trigger, like yours.
Then I'd like to add a pistol grip of some sort to this sliding mechanism.

Thanks for the great ideas.

Paul in Oregon
 

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Here's a photo of the simple 2 arm trigger mechanism.

Although there is no automatic trigger setting, when you have the pouch in hand, it is trivial to close the arms and lower the trigger in a single motion.

Easy peasy, cheap, no metal cutting, and best of all, it works great.

I strongly suggest that you consider a fixed fork and a movable ratcheting trigger.

It is much easier to draw towards you with 2 arms than away from you with one.

When I draw the trigger mechanism towards me, my hands are on the hinged 'sear' holding it down for safety.

Joerg has shown us a very straightforward way to make a strong, safe trigger out of wood, why work so hard to cut steel?


[/quote]

Stu,
I have the forward plate mounted on the clamp frame, for the fixed "Y".
I put a piece of wood inside of the bar and screwed a platform on top of that.

Then I took apart the screw mechanism (the clamp parts) and used both sliding blue pieces to mount the lock plate, the kind with two swing arms.
Now to make a trigger, like yours.
Then I'd like to add a pistol grip of some sort to this sliding mechanism.

Thanks for the great ideas.

Paul in Oregon
[/quote]

You are welcome.

Several others are in the process of purchasing a 48" aluminum clamp from Harbor Freight.

I look forward to seeing how folks will improve my basic design.

Incidentally:

Shooting a triggered rifle that you draw with 2 arms offers some significant health advantages:

Prevents wrist strain and Carpal Tunnel Syndrome, avoids tennis elbow,

See slingshotbill's video:

A rifle is Inherently more accurate than a slingshot.

If we could fold it up and carry it in our pockets, it would be perfect!

I am in an area where there are 3 Harbor Freights that are near me.

My clamp was on sale for $8.99!
 

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Discussion Starter · #19 ·
Ok, here is the first attempt at the HF 48" bar clamp doozie.
Right side view.


Same kind of lock plate, aluminum and plastic.
The tubing is the 5/16" stuff from local hardware store.


I guess I'll have to hold it like a bazooka, for now anyway.

Paul in Oregon
Two more pix at the bottom of: Bar Clamp 48"
 

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Ok, here is the first attempt at the HF 48" bar clamp doozie.
Right side view.


Same kind of lock plate, aluminum and plastic.
The tubing is the 5/16" stuff from local hardware store.


I guess I'll have to hold it like a bazooka, for now anyway.

Paul in Oregon
Two more pix at the bottom of: Bar Clamp 48"
Bravo!

You have made great strides in using the bar clamp parts to mount the trigger mechanism.

Your use of Plexiglas makes it very interesting and quite beautiful.

Hint: I used an "L" shaped piece of plywood for the Boynton-Banger stock..

I used the original hole for a screw and nut.

(The rubber should be parallel to the barrel.)

Great job!
 
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