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sundevil777

Are "good" pins good enough?

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Instead of just focusing on breaking, it seems more prudent to think about bending as well as breaking. Breaking is an obvious issue, and the results are obvious. However, a bent pin is more of a silent killer. It can easily go unnoticed on quick visual inspection and make it dramatically harder to pull the reserve when it's needed.

Better QA in from the pin manufacturer seems like the most cost-effective solution. Increasing the pin diameter might be a good stop-gap, but how long before container manufacturers use that as an excuse to increase spring-force on the reserve PC?
Trapped on the surface of a sphere. XKCD

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Just out of interest, what proportion of the ripcords you make fail the test and get binned.



As a manufacture of complete ripcords, pins and handles, the complete system failure rate is somewhere around one in five hundred. We 100% test each component and then the complete system. Our welders are AWS certified and we TIG weld our handles. The handles have to pass a 40lb. pull and ours fail somewhere around 1800lbs. Our pins can take up to three 90-degree bends before failing. The standard is an 8lb. side load at four 90 angles. Every batch of steel is lab tested and pin tolerances are maintained within +- 0.002" by use of an optical comparator.

Every good manufacture in the industry will take you on a tour of their factory, show you how the products are made and answer your questions. I would strongly recommend you take advantage of this, as all manufactures are not created equal.

Stay safe,
Mike Forsythe
Jump Shack

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This is starting to worry me a bit. If the quality of materials fluctuates (pins, webbing, etc) and there are sections of the TSO standard that only apply to the design, how many rigs out there wouldn't pass the TSO because the quality of the materials has changed since the initial certification???? Very scary



If the manufacture is doing their job right this should not be an issue. We 100% test all of our raw materials. We not only pull test our webbing to the needed standard but rather to the failure point. The reason is because lets say the passing point for a particular type of webbing is 7500lbs. and the sample passes but it fails when it reaches 8000lbs. where normally we don't see it fail until at least 9500lbs. we will reject the lot even though it passed the pull test. The same goes for all of our raw materials.


Stay safe,
Mike Forsythe
Jump Shack

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Bill & Mike,
Thanks to both of you for being so open about what goes on in your shops. I am sure this helps some of the newer jumpers and the older ones for that matter, feel more secure is the gear they jump. As always, knowledge is power and you are providing knowledge to many.B|
Sparky
My idea of a fair fight is clubbing baby seals

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sundevil777

I am suprised that nobody has raised the question of whether the existing design is adequate.

We've have had the opportunity to see the test procedure (15 lb applied a short distance from the loop) and I think pins should be able to withstand a LOT more than this.

I have read and heard of many instances where riggers admit they can bend a pin with too much tension on a closing loop. Years ago I noticed a bent pin during a friends gear check. In my opinion this should simply NOT be possible for a rigger to do this, or for you to do it to yourself by leaning back on something.

We should not have to rely on a reserve pull force limit to control excessive tension and resultant bent pins.

Maybe all such incidents were examples of defective pins. I don't think so.

The strength could be increased in many ways. A slight increase in the diameter would help greatly (does moment of inertia increase by the radius/diameter ^3 for a circular cross-sec?).

If a rig manufacturer offered a rig with a much stronger pin, I believe it would be very popular.

In an earlier post I stated my opinion on the inadequacy of ripcord pins, nobody had any comment on the subject, so I bring it up again.

What do you think?



I'm resurrecting my old thread because of a bent pin on my rig. It was only slightly bent. I don't know how it happened. My rig isn't a tight fit for the reserve, and I'm very careful to not lean back hard on it.

This just shouldn't be possible. Excessive loop tension shouldn't be able to do it, leaning back on something shouldn't be able to do it, slamming into the door on the way out shouldn't be able to do it.

I realize that a "slight" bend should not be critical in terms of driving up pull force, but I still think that it should be a non-issue that shouldn't need to be tolerated. We don't really know how much bend is too much, or what it takes to get too much of a bend.

As far as I can tell, the UPT "separate" pin that works with their unique design of ripcord is the only alternative that appears to be an improvement. Unfortunately it can't be just swapped out and used on other rigs. It would be possible if mfgs made slight changes.

We should not be so complacent that the current, nearly universal design continues to be accepted as good enough.

So many things about our rigs have been improved for safety reasons, or for aesthetic reasons. The "market" has found many of those changes desirable despite higher costs. I think a better reserve pin would have high market appeal, if it is actually highlighted as an improvement (UPT ought to take advantage of this).

What do you think?

Imagine it being your pin that was bent.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Also, I know that my ripcord was made many years after the old issue of sub-standard pins and the capewell service bulletin.

It would be interesting to check the bent pin per that service bulletin. I've always thought that the strength required to pass that check was not enough to give me confidence.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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dpreguy

Increasing the diameter of the pin will require a higher pull force to extract it.

Could you say more? I'm not sure this is correct. Some thoughts:

. . . The larger pin-loop contact area means more area for friction, but that might be balanced by reduced pressure per square millimeter of contact area with a larger pin.

. . . Skyhook pins are substantially larger than conventional pins, but there don't seem to be issues with harder pulls. IIRC, Sunpath currently allows both conventional-pin ripcords (for set-up without RSL) and Skyhook pins (for RSL/Skyhook), without any mention of pull-force issues.

. . . This seems similar to the argument (false, I think) that Racers have higher pull forces because they have twice the number of pins compared to most of the other rigs on the market.

Mark

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dpreguy

Increasing the diameter of the pin will require a higher pull force to extract it.



Physics textbooks and such will say that frictional force equals the coefficient of friction for a particular combination of materials x the force applied perpendicular to the contact surface. The coefficient of friction is not dependent on area, and the normal force (not pressure) is also not related to area. This simplistic relationship isn't always correct, as tires can actually conform and stick to a road and give much more frictional force (traction) than the force pushing down on the tire, and it explains why the contact patch for a tire does matter.

Most other types of contact friction do closely follow the simple formula and are relatively independent of the area of contact. I think this would apply for metal to spectra friction.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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sundevil777

I'm resurrecting my old thread because of a bent pin on my rig...
So many things about our rigs have been improved for safety reasons...



Reserve pins have to be soft metal because that allows the shank to be swaged onto the steel cable, where under great pressure the metal flows into the fibers of the cable for a tight grip. So I guess the trick is to have a pin hard enough not to bend, and at the same time, soft enough to be swaged. If you had a hardened steel pin, then you've got to figure out a new way to attach the pin to the cable...

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TomWatson

***I'm resurrecting my old thread because of a bent pin on my rig...
So many things about our rigs have been improved for safety reasons...



Reserve pins have to be soft metal because that allows the shank to be swaged onto the steel cable, where under great pressure the metal flows into the fibers of the cable for a tight grip. So I guess the trick is to have a pin hard enough not to bend, and at the same time, soft enough to be swaged. If you had a hardened steel pin, then you've got to figure out a new way to attach the pin to the cable...

Yes, a new way to attach to the cable would definitely free up ways to make it stronger. I would first make it a larger diameter, and would avoid heat treating as part of the solution.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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I also have concerns about the slight bending back and forth over the years of use. I feel much better jumping my Vector with that fat pin than the tin pins in the other rigs I have.

I have considered replacing the reserve rip cords in my rigs, but who is to say that the new pins are not any better...

A conversation in a different thread comes to mind, and off the top of my head I do not remember the specifics other than it was an interpretation debate regarding a riggers ability to replace or substitute parts of a TSOed system, like swapping a reserve pilot chute for a different one.

If a rigger can indeed change a reserve pilot chute, why could he/she also replace the reserve rip cord with one that meets the TSO requirement? I would love to have a UPT pin in all my rigs.

Have I totally miss understood what the discussion regarding a riggers ability to interchange parts?

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If a rigger can indeed change a reserve pilot chute, why could he/she also replace the reserve rip cord with one that meets the TSO requirement? I would love to have a UPT pin in all my rigs.

Have I totally miss understood what the discussion regarding a riggers ability to interchange parts?



The new Vector ripcord does not have the pin swaged on the cable. I believe that adapting that setup would require the bit of velcro and tab on the RSL lanyard, and I'd assume that would not be something that a rigger would see as "interchangeable parts".
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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sundevil777

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If a rigger can indeed change a reserve pilot chute, why could he/she also replace the reserve rip cord with one that meets the TSO requirement? I would love to have a UPT pin in all my rigs.

Have I totally miss understood what the discussion regarding a riggers ability to interchange parts?



The new Vector ripcord does not have the pin swaged on the cable. I believe that adapting that setup would require the bit of velcro and tab on the RSL lanyard, and I'd assume that would not be something that a rigger would see as "interchangeable parts".



More importantly the rig has to be packed in accordance with manufacturer instructions using the approved components. Not only would that not be in accordance with manufacturer instructions but if it were done it would constitute an alteration to the system which would require a master rigger and approval they aren't likely to get. I know I wouldn't do it and don't see it as "interchangeable" if someone brought that request to me.
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mcordell

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If a rigger can indeed change a reserve pilot chute, why could he/she also replace the reserve rip cord with one that meets the TSO requirement? I would love to have a UPT pin in all my rigs.

Have I totally miss understood what the discussion regarding a riggers ability to interchange parts?



The new Vector ripcord does not have the pin swaged on the cable. I believe that adapting that setup would require the bit of velcro and tab on the RSL lanyard, and I'd assume that would not be something that a rigger would see as "interchangeable parts".



More importantly the rig has to be packed in accordance with manufacturer instructions using the approved components. Not only would that not be in accordance with manufacturer instructions but if it were done it would constitute an alteration to the system which would require a master rigger and approval they aren't likely to get. I know I wouldn't do it and don't see it as "interchangeable" if someone brought that request to me.

It would obviously have to be something that would not have to be "approved" by the manufacturer in order to be able to be done, as no manufacturer would approve of a competitors component on there rig. I don't remember if John Sherman was sighting the language that I am thinking about when he was playing with his power rip cord. I don't remember if he thought you would need the manufacturers approval to install one, or be a rigger for that matter, but I might not be remembering correctly.

A "Plan B" that I would be more comfortable with than the skinny pins spanning the grommet, (not "exactly" as they were designed for, albeit close), with "a lot" of tension on them, would be a larger diameter pin of the same material, just scaled up so to speak. If a fatter pin was made in the same process and from the same material, where would the conflict be? If the standard skinny pin made in the same process and from the same material meets the requirements, the surly increasing the pins cross section would not render the pin non compliant would it?

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Slightly bent pins are not uncommon. Few pins are dead straight after a few years, not an issue, never has been. Some rigs that have the pin and protector flap as the highest point of the container seem to be more susceptible. Also the Reflex with the design of the stiffeners routinely bends a little. My pin is usually bent. If you haven't seen one in 33 years you haven't been looking.

As above pins have to be soft enough to swage to the cable. We could go back to wire wrap and solder, which the Chinese still use.

If you're worried about your ripcord have your rigger test to according to the Capewell service bulletin, the block and weight not the pull up cord field test. It's very important they have the right diameter and depth hole for the test. Capewell distributed aluminum blocks with various holes to cover all the available pin lengths. An individual test hole can be be drilled as needed. There is another test that uses a shallower hole. I'm on my phone and can't look up the reference.

IIRC there is or was a fatter pin on the market but nobody sees the need to use it.

The Capewell problem was caused by two issues. One blank stock for making the pins that has included flaws. The forging process tended to cause those flaws to migrate to and concentrate at the shoulder. Second the dies used by Capewell were old and worn. Capewell was very up front about all this information and corrected the incoming inspection process and replaced the dies. BTW I still occasionally get rigs in that have ripcords covered by the service bulletin that haven't been tested. Riggers should still be checking.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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I've seen bent pins before, just never on my rig. The first one I saw during a pin check before boarding the plane. That guy stayed on the ground, and a rigger tried (unsuccessfully) to pull the ripcord. He eventually just gave up and pulled the pin by pulling on the cable like an RSL.

I've had older ripcords checked by the block and weight test. In my opinion, that test shows that the pins aren't expected to be very strong. The capewell problem should have caused us to realize that we deserve better.

We don't know how much of a bend will cause real problems with high pull force, and we shouldn't have to. We should have pins that are much stronger than required instead of a little bit.

How is a rigger to judge whether a bent pin is OK to use during a repack?
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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sundevil777

I've seen bent pins before, just never on my rig. The first one I saw during a pin check before boarding the plane. That guy stayed on the ground, and a rigger tried (unsuccessfully) to pull the ripcord. He eventually just gave up and pulled the pin by pulling on the cable like an RSL.

I've had older ripcords checked by the block and weight test. In my opinion, that test shows that the pins aren't expected to be very strong. The capewell problem should have caused us to realize that we deserve better.

We don't know how much of a bend will cause real problems with high pull force, and we shouldn't have to. We should have pins that are much stronger than required instead of a little bit.

How is a rigger to judge whether a bent pin is OK to use during a repack?



By using the standard prescribed method and testing pull force. It's really not hard and a slightly bent pin isn't a problem as long as it doesn't increase pull force boy on 22 pounds. I don't come across bent pins all that often and when I do the are only very slightly bent. I don't think it is a problem worth throwing a bunch of money at. It could be solved by using a hardened steel pin inside the softer steel to allow the pin assembly to be swaged onto the cable but why would manufacturers buy the more expensive pins and raise their prices in a competitive market when the pins we use now aren't a problem?
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mcordell

***I've seen bent pins before, just never on my rig. The first one I saw during a pin check before boarding the plane. That guy stayed on the ground, and a rigger tried (unsuccessfully) to pull the ripcord. He eventually just gave up and pulled the pin by pulling on the cable like an RSL.

I've had older ripcords checked by the block and weight test. In my opinion, that test shows that the pins aren't expected to be very strong. The capewell problem should have caused us to realize that we deserve better.

We don't know how much of a bend will cause real problems with high pull force, and we shouldn't have to. We should have pins that are much stronger than required instead of a little bit.

How is a rigger to judge whether a bent pin is OK to use during a repack?



By using the standard prescribed method and testing pull force. It's really not hard and a slightly bent pin isn't a problem as long as it doesn't increase pull force boy on 22 pounds. I don't come across bent pins all that often and when I do the are only very slightly bent. I don't think it is a problem worth throwing a bunch of money at. It could be solved by using a hardened steel pin inside the softer steel to allow the pin assembly to be swaged onto the cable but why would manufacturers buy the more expensive pins and raise their prices in a competitive market when the pins we use now aren't a problem?

We disagree on whether the strength of the existing pin is good enough. I think we deserve a larger margin of strength.

I kept a friend of mine from using his rig which had a bent pin so bad he had no reserve available to him. This was pre-cypres days, so he didn't even have that potential saving mechanism.

I think we should be able to lean back hard, or hit the door frame hard and not be concerned about a bent pin. I think it is worth a little money, and it could be marketed as a selling point.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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I'm not sure there are enough jumpers out there that would spend extra money to buy a stronger pin. I have 3 rigs, one of which is a vector from 1986 with the original pin and none of my 3 are bent. I think the problem isn't the pin as much as it is jumpers trying to stuff reserves into smaller and smaller containers and putting more pressure on the pin than necessary.
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mcordell

I'm not sure there are enough jumpers out there that would spend extra money to buy a stronger pin. I have 3 rigs, one of which is a vector from 1986 with the original pin and none of my 3 are bent. I think the problem isn't the pin as much as it is jumpers trying to stuff reserves into smaller and smaller containers and putting more pressure on the pin than necessary.



My rig is not overstuffed and suffered a bent pin, and I also am careful about leaning against things.

It would be interesting to know what loop tension is needed to start bending a pin versus what loop tension will result in reaching the limit for allowed pull force. I think they are not very far apart.

I agree that typical jumpers won't want to spend money on something if there is no perceived benefit. That perception could change if there were some marketing to highlight the improvement. Show how pull force goes up for as the bend gets greater. Show how easy it is to bend a pin from leaning against a structural frame or whatever. Make the pin and/or cable some cool color then price won't be a problem.

My friend's pin was so badly bent that it couldn't be pulled (it was early 90s). He was a newbie, not so likely to catch it himself, so he may have put many jumps on the rig that way.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Reserve pins have to be soft metal because that allows the shank to be swaged onto the steel cable, where under great pressure the metal flows into the fibers of the cable for a tight grip. So I guess the trick is to have a pin hard enough not to bend, and at the same time, soft enough to be swaged. If you had a hardened steel pin, then you've got to figure out a new way to attach the pin to the cable...



Ripcord pins are made from .188 dia 302SS Cond A (303 is also allowed but I don't use it) they are then rotary swaged to a diameter of .094 using the rotary Swag process of cold forming as you can't harden SS with Heat treat. The overall length of the blade is dictated by the end user but is usually 1.25 inches. Column strength of the blade is tested by inserting it into an .096 dia hole one half inch deep and applying an 8 pound weight to the end. The results is checked in a go-no go gage of .104 dia to the full depth and the pin must fall out without friction after insertion.
This process and design was originally for a pin and metal cone thru a 9/16 and 7/16 grommet situation. The amount of allowable bend was critical as the thru hole in the cone was about a half inch deep/thick.
Today we use 1/4 inch grommets with a cloth loop. A far less critical arrangement.
Yes, the pin can bend in that configuration but it is usually from dropping or throwing the rig down or against something as the rig is compressed when it hits something and this causes the rest of the rig to want to expand causing a great load on the loop and subsequently on the pin causing a bent pin. The good news is that is can still be pulled even with a bend.
The Military still uses this pin on their center pull chest reserve with cloth loops and even with the rough treatment they get have had no problem.
Larger diameter pins would cause a harder pull with the same loop load. Additionally, the shank and cable would also have to be enlarged to obtain the necessary strength as the blade would still have to be cold formed to make it hard enough.
The thicker pins used on some assemblies have no greater column strength as they are not cold formed from a larger diameter. Don't let size fool you.

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JohnSherman



The Military still uses this pin on their center pull chest reserve with cloth loops and even with the rough treatment they get have had no problem.



I think you meant to say that the "old" center pull Military chest reserves used them. The "new" T-11R chest mount reserve replaced the old center pull reserve, and uses two curved pins. The activation direction is to pull forward as apposed to up so the curved pins are needed.

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JohnSherman



Ripcord pins are made from .188 dia 302SS Cond A (303 is also allowed but I don't use it) they are then rotary swaged to a diameter of .094 using the rotary Swag process of cold forming as you can't harden SS with Heat treat.



I am sure you know that 303 Alloy Stainless Steel can not be hardened via heat treating, but also that other alloys of Stainless Steel can be heat treated.

Heat treating is a blanket term, and people generally think that it means that the material is being made harder and that is not all ways the case. There are many different Alloys of Stainless Steel, and different heat treating processes that some of the alloys respond to that result in different material conditions after processing. Some times the result is the material being harder, some times it results in the material being tougher. Sometimes it results in the material being softer or stress revealed..

JohnSherman


The thicker pins used on some assemblies have no greater column strength as they are not cold formed from a larger diameter. Don't let size fool you.



The accuracy of the statement is dependent on the material used and its condition. For instance, if the UPT pin that you are referring to were made from 17-4 Stainless Steel in the H900 condition (heat treated with 40Rc) the strength and toughness would be way higher than the 303 regardless of how it was processed..


I use 17-4 PH 900 for the pins in my timers, and they are the same size I think as the standard reserve pin. I will try to remember to compare them when I have a min in the shop. I have a few rip cord pins laying around so that might be a fun comparison, who knows, I may be all wet lol…

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