Author Topic: A new? patchbox release spring  (Read 8931 times)

Offline Mark Elliott

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A new? patchbox release spring
« on: December 30, 2015, 03:45:33 AM »
I decided to share the following photo knowing that I am opening myself to some criticism for not forging the spring.   If you don't need to be absolutely historically correct,  this is a quick and easy way to make a spring.

The photo shows a slightly updated implementation of a very old patchbox release mechanism.   The part that is new to me is the design of the release spring I used.   I cut the L shaped spring out of 1/32" 1085 with aviation snips.   It was quick and easy.   I just had to drill two holes for the slot and cut out the waste between with a jeweler's saw.  Then I drilled and countersunk the hole for the screw.  Next to last, I bent over the little tab at a 90 degree angle.  The final step was to heat the tip and bend it over with some needle nose pliers to form the hook to engage the catch.  I did reduce the the amount of hook on the belt sander.  

Inletting was done with a 1/4" chisel and a 1/16" morticing chisel.   I had to just cut a slot a little wider than the spring is thick and inlet the roughly square tab.   The tab inletting and a nice tight screw keeps the spring in place.  

You might ask what I was doing before.   Well I was making a V shaped spring that had one leg tightly inlet into the butt stock.  It was always hard to inlet.   The other method was to forge out a spring with a similar 90 degree tab that I could screw to the butt piece.    Getting that positioned correctly is a bit tricky.   Putting the spring in the right place with it attached to the buttstock is easier.  

The pushrod was forged out of 5/16" mild steel rod.   I decided to hold it in place with a pin because it keeps the pushrod from getting wedged into the butt piece.  

Anyway,  here is what I did; a modern update to an old design.

« Last Edit: December 30, 2015, 03:47:48 AM by Mark Elliott »

Offline smylee grouch

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Re: A new? patchbox release spring
« Reply #1 on: December 30, 2015, 03:53:30 AM »
The flat push rod against the flat spring might stay in place better than my round push rods that almost always seem to end up hitting the spring at an angle and not working as well as I want.  Thanks for the tip.

Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #2 on: December 30, 2015, 03:56:57 AM »
The flat push rod against the flat spring might stay in place better than my round push rods that almost always seem to end up hitting the spring at an angle and not working as well as I want.  Thanks for the tip.

That isn't my idea.   I just copied from an original.   My only contribution is how I made the spring.  Also note that the pushrod goes through the spring and is pinned on the other side.   It is mechanically connected to the spring.   
« Last Edit: December 30, 2015, 03:58:26 AM by Mark Elliott »

Offline Ed Wenger

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Re: A new? patchbox release spring
« Reply #3 on: December 30, 2015, 03:57:26 AM »
Well Mark, I for one like it.  I've done similar catches with the same material.  Mine were bent into a "J" shape.   A sharp edge was filed on the lower part of the "J", and this was simply driven into the wood.  If that makes sense....


      Ed
Ed Wenger

Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #4 on: December 30, 2015, 04:00:09 AM »
Well Mark, I for one like it.  I've done similar catches with the same material.  Mine were bent into a "J" shape.   A sharp edge was filed on the lower part of the "J", and this was simply driven into the wood.  If that makes sense....


      Ed

That is pretty much the same idea as my V shaped springs.    I tried the J shaped but they didn't hold as well as I would like.  So,  I extended the J into a V.  Actually,  I guess it was somewhere between an L and a V.
« Last Edit: December 30, 2015, 04:01:13 AM by Mark Elliott »

Offline Topknot

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Re: A new? patchbox release spring
« Reply #5 on: December 30, 2015, 07:05:39 AM »
Looks good to me. Good job Mark!
TIM COMPTON, SR.

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Offline Acer Saccharum

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Re: A new? patchbox release spring
« Reply #6 on: December 30, 2015, 07:22:53 AM »
Mark, that is way too complicated. This was much simpler. A sliding bolt, and a notch cut into the buttplate, and a little spring. Done.

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Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #7 on: December 30, 2015, 07:27:28 AM »
Mark, that is way too complicated. This was much simpler. A sliding bolt, and a notch cut into the buttplate, and a little spring. Done.


;D

Offline flehto

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Re: A new? patchbox release spring
« Reply #8 on: December 30, 2015, 09:14:50 AM »
Mark...that's a  nice setup.....pretty neat. Shown below is a sketch of a Pbox release that I've used on all my LRs. ...if the release terminates in the Bplate return.

The separate button is made from a wood screw and allows for  a perpendicular hole in the Bplate return. The rod is a straight length of nail. The catch spring is .015 thick hardened and tempered spring steel.  The rod can have a smaller dia on one end which would fit into a hole in the catch spring. This  release is also easy to make.....Fred

  
« Last Edit: December 30, 2015, 09:19:42 AM by flehto »

Offline Tim Crosby

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Re: A new? patchbox release spring
« Reply #9 on: December 30, 2015, 04:22:26 PM »
 Neat Mark. can we see an end view with the lid on and latched?

  Thanks, Tim C.
« Last Edit: December 30, 2015, 04:25:50 PM by Tim Crosby »

Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #10 on: December 31, 2015, 04:51:52 AM »
Here are the new views as requested.



Offline David Rase

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Re: A new? patchbox release spring
« Reply #11 on: December 31, 2015, 07:41:42 AM »
Mark,
How hard is the release to push.  Looking at where the pushrod contacts the spring, it looks like it would take a lot of force to move the spring to unlatch the door.
David

Offline Tim Crosby

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Re: A new? patchbox release spring
« Reply #12 on: December 31, 2015, 03:57:40 PM »
 Thanks Mark. TC

Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #13 on: December 31, 2015, 05:26:31 PM »
Mark,
How hard is the release to push.  Looking at where the pushrod contacts the spring, it looks like it would take a lot of force to move the spring to unlatch the door.
David

It takes little force as you don't need to move it much and the slot in the spring weakens it significantly. It also matters where You tighten down the screw/spring. The spring can be rotated a bit. Also note that the pushrod presses at the top of the slot.

Offline oldtravler61

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Re: A new? patchbox release spring
« Reply #14 on: December 31, 2015, 06:49:17 PM »
Mark I like it. Simple clean functional. Nice work.

Offline Pete G.

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Re: A new? patchbox release spring
« Reply #15 on: December 31, 2015, 07:31:33 PM »
Very neatly solves the problem of drilling an angled hole and I particularly like the idea of the flattened pushrod.

Offline D. Taylor Sapergia

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Re: A new? patchbox release spring
« Reply #16 on: December 31, 2015, 07:39:19 PM »
Mark, I like it too.  The pushrod pushes quite a long way up the spring so I can imagine the pressure required is about right.  What I look for is a stiff button with only a short throw...you've got that.

I also like Fred's drawing...it wouldn't have occurred to me to use a two piece system - brilliant!  The hole for the long 'nail' would keep everything in alignment. 

But Acer's release, for it's mechanical features, is my favourite.  That little return spring with the snake head...lovely.
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Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #17 on: December 31, 2015, 07:40:20 PM »
I forgot to note that I heat treat the spring by hardening and tempering to 700 F.   

Offline Mark Elliott

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Re: A new? patchbox release spring
« Reply #18 on: December 31, 2015, 07:44:49 PM »
I also like Fred's drawing...it wouldn't have occurred to me to use a two piece system - brilliant!  The hole for the long 'nail' would keep everything in alignment. 

I have seen a 19th C PA rifle using a thin pushrod (like a finish nail) tapered on the end to go in a hole in the catch/spring.   It keeps the rod in place once the toe plate was in place.