Primitive Archer
Main Discussion Area => Bows => Topic started by: Marc St Louis on May 29, 2018, 10:29:19 am
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I know there are some here that have made them and use them to chronograph their bows. I'm thinking of making one and would like to see some pics of the ones that members have made
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The one i have now is junk, my last one was much better but I didn't have enough room for it. A few things that I think are good to keep in mind when you build one. If you get one of those compound bow releases get the one with a thumb activated trigger, it is much easier to set up an adjustable automatic triggering spot. The thumb release triggers by pushing while the others trigger by pulling. So you can just pull the string until it hits the block and fires. Another thing is I like a pulley on the back end with a stirrup that I can step into and use my foot to draw the bow. This works best if you partially draw the bow by hand to preload it so you don't have to step up so high to get your foot in the stirrup. For holding the bow I prefer one of those little short cargo straps. When I do my next one I am going to split the strap down the center so I can force a simple wedge through it into the machine base to block the bow into the strap.
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I pretty much copied Del's so you can compare it with the pictures on his blog.
It breaks down into two pieces for storage.
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The saddle that the bow sits in needs work. Sometimes the bow slips sideways, I haven't figured out why.
The screw that's sticking up is the release and you can adjust the release position quite well by screwing it up or down.
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I always wanted some,, I dont think I could build something like that,, a self bow is about my limit,, -C-
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Thanks Don. I think I can work with that
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Yo DC ... I thought that looked familiar ;D
Some pics of mice here.
https://bowyersdiary.blogspot.com/2018/01/mk2-shooting-machine.html (https://bowyersdiary.blogspot.com/2018/01/mk2-shooting-machine.html)
Del
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Del, do you have any detail on how you built your trigger, I really like that.
Never mind, I think I see the detail in the photos above.
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Very cool, thanks for posting pictures Don and Del.
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Del, does your saddle grip the bow tightly? Packed in foam maybe?
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I use a modified rotary latch for the trigger and release system. It is very robust, inexpensive, and easily handles thousands of shots with 250#+ bows. It is also easily adapted to mounting to a sliding fixture with automatic triggering. I’ll get some photos together.
Alan
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Del, does your saddle grip the bow tightly? Packed in foam maybe?
I wrap the bow with rubber sheet and then tighten it up with a wing nut, so it's not rock solid.
Del
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Thanks, I'll try that.
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Another question, do you have any grippy stuff on the "fingers"? Because I'm pulling from one side the serving slides on the fingers and the "Top" of the bow rocks "back". Quotes are because my bow lays on it's side and I'm translating into verticalise.
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For anyone considering copying any of this you might want to beef up the bow mount. In this picture I pull the bow from the right and it split the 2x4 and this was only a 40# bow. I'm thinking laminated 3/4 plywood.
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D/C, the wood was plenty heavy enough, your grain was running the wrong way. I got away from the solid mounts and switched to a strap, I like it a lot better.
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I'm having a tough time imagining a strap that keeps the bow from flopping around. Picture maybe?
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The strap only holds it from coming toward you, it has to be backed up by something solid. I will get a pic tomorrow. I threw together another shooting machine a few weeks ago but plan to rebuild it very soon. The strap is the only thing I like on it. I really like Allens latch for the release.
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I'm waiting for a picture of Allens release. I'm not sure what a rotary latch is.
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I looked it up, a lot like a door latch in a car or truck. I have some 1 1/4" delron rod, I am going to try and build your style latch from the Delron before I go to the rotary. My compound release I done really trust past about 100#
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Yeah, I just did too. Hood latch is what i thought of. They look like they would work all right.
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There's a point that is easy to overlook and isn't intuitive.
You want the release point to be quite a way above the track to avoid the string slapping the track*, as there is a lot of string vibraion and arrow flex especially in flight bows.
I can take detail pics of my set up if anyone wants to see anything specific. (Not that I'm claiming my one is anything special or in any way ideal ::) )
Del
* Unless you want to make a bracer for the machine ;D
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Del, I would appreciate more detail on your machine.
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Del, I would appreciate more detail on your machine.
I'll take a load of pics, put 'em on my blog and post a link :)....
Wait there!
Del
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Loads of detail pics on my blog now, here:-
https://bowyersdiary.blogspot.com/2018/05/shooting-machine-detail.html (https://bowyersdiary.blogspot.com/2018/05/shooting-machine-detail.html)
Del
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Thanks Del :). Why did you use the leather tab on the release?
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This shows a before and after conversion of what I did with this small rotary latch. Depending on the latch, the modifications don’t have to be this complicated. I ground a notch in the latch to act like a hook for the string loop, but the hook could just as easily be placed directly on the bow string. I put this latch in a housing that slides on a piece of t-track. The trigger piece behind it also attached to the t-track, and I slide this to the position that I want to trigger the release. The latch slides back and pops open as soon as the latch release lever contacts the plastic finger on the trigger. It works great every time and doesn’t fail for thousands of shots at very heavy draw weights (unlike many compound releases). It is a very smooth, reliable, and easy to adjust so i am pretty happy with it.
(https://farm2.staticflickr.com/1741/41753166334_fe232a8a48_z_d.jpg)
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Thanks Del :). Why did you use the leather tab on the release?
Just trying to simulate a manual loose, and in the hope that it would be less harsh with less string vibration. I think the string was maybe slipping off the nut before it had rotated fully (not sure it was rotating fully, so I tweaked it).
Del
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Thanks Del and Allen
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I really like your set up Del, I like the idea of flight shooting with a machine when I get too old to draw the bow.
Allen, what was the intended application for that latch, would you select the same one if you did it over?
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Allen, what was the intended application for that latch, would you select the same one if you did it over?
The original purpose for this latch was for the front grille/hood for a Freightliner Argosy Cabover. I like the compact design and the way it snaps open. The release is very clean when used with the release loop, which is what I need for my foot bow. However, I would use a larger latch if I were trying to simulate a finger release, and I would build out thickness on either side of the claw to simulate three fingers on the string.
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I had a feeling it was freightliner!
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A small ‘quick-release’ for ropes and such are fairly inexpensive
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Bryce, do you know what they are called?
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The ones we used in search and rescue where called ‘fast-rope; quick release’
I’ve seen some at wal mart as well where it’s a pin pull type release, a panic snap release.