Ropetek Hitch Hiker

[tophopper]

Very well done Paul!

 

[PCTREE]

Paul, have you thought of using a 300 series SST to keep from corroding and not needing to coat it?
304 or 316 sheet form nice in bend dies.

We even made them out of 410 stainless but the problem is the contact between the steel biner which is constantly moving and when locked under high load = wear . Stainless is too soft. We will try 4140 pre hardened steel this weekend to try to save the heat treating process, my machinist thinks it will do the trick....

 

[bonner1040]

Pretty sweet, I'd buy one, but I wouldn't pay a lot. no offense. I'm sure a lot of time and money went into making it, but once it's in production it's really just a stamped out piece of metal you add some carabiners too. which is awsome by the way, brilliant and simplistic. you'll be like the paperclip guy, selling millions of something inexspensive.

I will buy one of the production models, and I will pay what Paul asks, I am sure it will be a fair price.

 

[CurSedVoyce]

Ditto.

 

[Reddog]

Makes sense, and the only way to make the SST harder/tougher is through work hardening. Which would mean going to a forging process.
4140 could be a good choice, tough and quite corrosion resistant for a carbon steel.
We had these folks do some coatings that held up well in forging dies. http://www.century-sun.com/centsun2.htm May be an option to reduce wear and offer some extra corrosion resistance if needed.

 

[emr]

I was intrigued by the WR but I had such bad luck getting the F8 Revolver to work, I just couldn't bring myself to buying on. This on the other hand looks almost like a no brainer. Have you noticed that you have to change your hitch configuration from what you usually use DRT? It would be nice if the same exact same hitch would work with the HH and in DRT without having to re-tie it. I sometimes go a couple of weeks without taking my hitch cord off and re-tying it.

 

[OTGBOSTON]

Awesome stuff Paul...just awesome.

 

[PCTREE]

On dDrt I use 7/16 tenex tied in a 3/2 VT. I would not advise anybody using tenex with the HH simply because I think a higher melting point cordage should be used for safety, I use Bline currently. Not sure if there is any validity to recommending these cordages but erring on the safe side cannot hurt. As to leaving the setup on the rope as you mentioned, I see no problem with that, in fact thats what I do and the HH can be used for dDrt if needed.....

 

[wiley_p]

Very interesting Paul.

 

[treesmith]

On dDrt I use 7/16 tenex tied in a 3/2 VT. I would not advise anybody using tenex with the HH simply because I think a higher melting point cordage should be used for safety, I use Bline currently. Not sure if there is any validity to recommending these cordages but erring on the safe side cannot hurt. As to leaving the setup on the rope as you mentioned, I see no problem with that, in fact thats what I do and the HH can be used for dDrt if needed.....

What is the reasoning behind this, Paul? I mean, for any length of descent, the hitch would run over more rope on DRT than on SRT, would it not? Not arguing your reasoning, mind you, just asking. In other words, if one were to rapidly descend 10' on Drt, 20' of rope would pass through the hitch, whilst only 10' would pass through it on Srt, and if the descents were at equal velocity, the Drt would move twice as fast at the hitch, thereby creating more heat/friction, at least in my thinking.

 

[PCTREE]

Yup that logic makes sense to me too Scott, however (not trying to be a dick) try inventing a device for life support which is TOTALLY dependent on the hitch and then see how you feel about it I am better about accepting the risks than I was when I started putting the Wraptor out but it is a very scary thought that you are responsible for ANY eventuality that may occur from the use of your product. IMO the higher the melting point of the hitch the less likely that the hitch cord can fail. As you stated in my configuration the hitch sees no more load than dDrt but what if a stick jams a biner or a small meteorite strikes it etc etc. It is hard to foresee ANY eventuality, bottom line is if your hitch holds you are fine so use a better hitch cord.....

As stated before I am paranoid.....

 

[SoonerFan]

I think you are borderline genius!

 

[wiley_p]

What is the reasoning behind this, Paul? I mean, for any length of descent, the hitch would run over more rope on DRT than on SRT, would it not? Not arguing your reasoning, mind you, just asking. In other words, if one were to rapidly descend 10' on Drt, 20' of rope would pass through the hitch, whilst only 10' would pass through it on Srt, and if the descents were at equal velocity, the Drt would move twice as fast at the hitch, thereby creating more heat/friction, at least in my thinking.

In Double rope Scott, the hitch is only bearing half the load. That equals less heat, than the same hitch on Single rope which has more pressure, and more friction.

 

[DMc]

What is the reasoning behind this, Paul? ...the Drt would move twice as fast at the hitch, thereby creating more heat/friction, at least in my thinking.

There is some very good information in this paper regarding hitch response in both DdRT and SRT configurations plus they did both pull tests and drop tests. Bottom line is there is a very good chance for the hitch to become welded to the line in an SRT fall so the danger in using a low melting point hitch cord is it requires less force to become friction-welded than one with a higher melting point.

The Hitch Hikers load sharing factor would need to be tested to determine how much it would alter these findings but it makes sense to recommend a high melting point hitch for any SRT work.

Dave

http://www.paci.com.au/downloads_public/knots/14_Report_hitches_PBavaresco.pdf

 

[sotc]

at half the weight...

 

[treesmith]

In Double rope Scott, the hitch is only bearing half the load. That equals less heat, than the same hitch on Single rope which has more pressure, and more friction.

I considered that, Dave, but I figured the higher speeds would counteract the fact that only half the load was experienced. Not only that, but wasn't the purpose of the HH (or F8, or RopeWrench,etc.) to share the load with the hitch, thereby negating the differences in Srt and Drt? In other words, the device "shares" the load with the hitch, doesn't it? So in essence, the hitch really sees no more load in either system. If it does, then the HH, RW, or any of these devices is not truly "sharing" the load with the hitch.

How many folks use tenex to start with as a climbing hitch? I know it is used somewhat, but to me, it's more a rigging prussik than life support. I prefer more heat-resisitant cord, period, for something I'll be hanging on.

 

[treesmith]

There is some very good information in this paper regarding hitch response in both DdRT and SRT configurations plus they did both pull tests and drop tests. Bottom line is there is a very good chance for the hitch to become welded to the line in an SRT fall so the danger in using a low melting point hitch cord is it requires less force to become friction-welded than one with a higher melting point.

The Hitch Hikers load sharing factor would need to be tested to determine how much it would alter these findings but it makes sense to recommend a high melting point hitch for any SRT work.

Dave

http://www.paci.com.au/downloads_public/knots/14_Report_hitches_PBavaresco.pdf

Dave, in Photograph 10 ( 6-wrap Valdotain), is that tied correctly? The legs are not braided, but merely wrap in the same order all the way down. If you look carefully, the leg that finishes on the left is on top of the other leg all the way down. I braid mine, so that one is on top, then the other. In fact, the only difference I see in photos 9 & 10, are that 9 finishes by tying back to itself, rather than coming down to the carabiner. Are my eyes deceiving me this morning?

 

[Burnham]

My thoughts echo yours, Scott.

For a redneck 'Bama boy, you think pretty good!

 

[treesmith]

Thanks, B! I try REALLY hard, ya know!

 

[Burnham]

Only way we can overcome our natural-born obstacles, isn't it .

 

[PCTREE]

Scott, yes by design the Hitch Hiker shares the load so that the hitch only "sees" the same load as with dDrt. However what if something fails, I cannot visualize how this could happen but it would suck if it did and you melted through the cord. One of the things I really like about the design is the more load applied to it the more breaking it does, I carried 90lbs of plates up a step ladder and dropped onto my hitch and the hitch still acted the same as with just my body weight.

Just got in from doing stumps,need to read the link from Dave and then go play with my Hitch Hiker Oh er sounds rude!

 

[NickfromWI]

Yes steel biners, in fact the device is very finicky about its biners to the point where I think we will provide biners with it. Price to be decided. What do you guys think a good price would be considering we will provide 2 $25 steel biners and a heat treated tool steel Hitch Hiker....

I'd say around $75. Definitely not more than $100. You're selling a single piece of machined metal with no moving parts. I think of micropullies selling for $18, and those carabiners with laser etched logos and all that sell for a similar price- of course they are all made and a much larger scale.

Please go with notch-free carabiners!!!

Whereas this one has that annoying notch that snags on things:

 

[PCTREE]

So is that $75 with 2 steel biners or without?? 2 biners = $35 which would leave $40 between materials , labour insurance and don't forget about $30 for retailers which would equate to not a viable product.....

Nick what carabiner is that top one in your picture??? Looks kinda like a Petzl Oxan but not quite

 

[Reddog]

We even made them out of 410 stainless but the problem is the contact between the steel biner which is constantly moving and when locked under high load = wear .

Thinking about this today and looking at the Tibloc and how the edges are rolled wear the biner attaches. You could do the same thing while piercing the holes in the first step of forming to SST 304. Then you wouldn't have the sharp edges to wear.

 

[kevin bingham]

I'd say around $75. Definitely not more than $100. You're selling a single piece of machined metal with no moving parts. I think of micropullies selling for $18, and those carabiners with laser etched logos and all that sell for a similar price- of course they are all made and a much larger scale.

You would think right? I thought the same... if only it were that simple.

PCTREE, that looks real cool, cant wait to give it a test drive. Been trying to imagine how it works in my head but can only guess.