JP AR Tension Pin or Alternative

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13 years 4 months ago #7946 by Tom S.
Replied by Tom S. on topic Re: JP AR Tension Pin or Alternative
Maybe you could take a standard pin and use an engraver on it to raise the surface and make it a tighter fit. The engraver I'm talking about is one of those electric 'buzz' types you can buy for around $10 if you don't happen to have one.

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13 years 4 months ago #7947 by Akai
Replied by Akai on topic Re: JP AR Tension Pin or Alternative
Not knocking what you suggested with the engraver, but I don't think that will last. Might be better off with the foam ear plug or expansion pin from Mcmaster, otherwise you might have to go to a machine shop and have them take the hole to your tolerances and put in a oversize pin. Right on with LebbenB!! Good luck and let us know what you come up with!
AKAI

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13 years 4 months ago #7949 by Tom S.
Replied by Tom S. on topic Re: JP AR Tension Pin or Alternative
Whether it works or not depends on how loose the pin is. The engraving trick is an old one used in the tool and die trade to tighten up loose dowell pins. It's not something I pulled out of my butt. :-)

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13 years 4 months ago #7952 by Bringsteen
Replied by Bringsteen on topic Re: JP AR Tension Pin or Alternative
Thanks to everyone that provided suggestions. I'll experiment with some possible solutions and then let everyone know what works for me.

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13 years 4 months ago #8124 by JustMe
Replied by JustMe on topic Re: JP AR Tension Pin or Alternative

Bringsteen wrote: Thanks to everyone that provided suggestions. I'll experiment with some possible solutions and then let everyone know what works for me.


Bringsteen,
What was your final solution?
Jer

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13 years 4 months ago #8125 by Bringsteen
Replied by Bringsteen on topic Re: JP AR Tension Pin or Alternative
The expanding-diameter pin from McMaster-Carr appears to be the best option, but I've not purchased it yet. For now the JP Tension Pin works great; it's just a hassle. The more broken in my barrel gets, the less I will need to clean it. I guess I might just shoot my way out of the problem;)

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13 years 3 months ago #8338 by Bringsteen
Replied by Bringsteen on topic Re: JP AR Tension Pin or Alternative
Well, I purchased the expanding-diameter pin from McMaster-Carr but it doesn't fit. The 5/16" pin is just too big for the 9/32" hole. I obviously knew that they were different sizes, but I gambled that the expansion would be able to be adjusted enough to make it work. The 1/4" pin is even farther away in size. So unless I can get someone to make me a custom 9/32" pin, I'll still be on the hunt for a solution.

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13 years 3 months ago #8339 by JustMe
Replied by JustMe on topic Re: JP AR Tension Pin or Alternative
Bringsteen,

Have you thought about drilling the hole out to make the expanding pin fit? You could cut a little out at a time and get it as tight as you want. You were talking about buying a larger non-expanding pin so, if the expanding pin doesn't work, just put in a larger pin and you'll be back to where you started, nothing lost.

I wish I had a milling machine, I'd make you an adjustable one that would fit. Seems like making an adjustable pin would have some marketability also as I'm sure others would like some adjustability.

Jer

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13 years 3 months ago #8340 by Bringsteen
Replied by Bringsteen on topic Re: JP AR Tension Pin or Alternative
I did think about drilling it out (or more realistically, having a gunsmith do it). The problem with that is that if for some reason the expanding pin doesn't work (in the sense that it doesn't keep the upper/lower connection tight), then I'll need a custom regular-style pin to put my rifle back to where it was. I like being able to go back to stock parts if I have to.

I've discovered that there is a threadlocker called Vibra-Tite VC-Threadmate, which can be adjusted multiple times. This may be the product I can use with my JP tension pin to make it less of a hassle.

But I can guarantee that if I happen across an expanding pin of 9/32" diameter, I'll be trying it.

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13 years 3 months ago #8341 by JustMe
Replied by JustMe on topic Re: JP AR Tension Pin or Alternative
Is there enough material on the expanding pin to have a machinist mill it down to the correct diameter?

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