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POLR 2 pin Binding 2018

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  • POLR 2 pin Binding 2018

    Well, not quite winter 2018 yet, but new thread anyway

    2017 thread:
    http://www.backcountrytalk.earnyourt...ghlight=jasonq
    From last year, i am totally happy with the dual under foot spring version. could be lighter, could be fewer parts, but works great.

    I have had a goal to make a DIY binding that could be built with stock spare parts, a few 3d printed parts, and some bits and pieces that could be made with a hacksaw, drill, and file. That turns out to be hard. This is my first failed attempt at it. failed because you also need and hand swage tool for swaging a stock cable stop, and 22Designs appears to have discontinued the hammerhead cable that i was planning on using. So i think i need to rethink how to deal with a simple to make cable. Aside from the cable, it would be a totally doable garage project. the answer may be a spectra/dyeema cord inside sheath for protection and sliding.

    so that said, here is the CAD of the attempt. Dual Axl springs under the toe piece. Axl/HH heel tube and modified HH cable. I'm using my own heel lever and heel pad, but the hammerheel and axl/hh lever work fine too. Designed for the hammerheel height. The entire spring cable assembly removes and replaces with no tools. fewer parts, easier to build. this is built for vertical ST/5 hole toes, but could easily be reworked for radical/speed turn 2 toes.

    Click image for larger version

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    I just ordered the 3d printed parts, so it will be real in a few weeks.

  • #2
    Whenever I think about the part of heel cables and the part of them that has to flex I think of bicycle or motorcycle chains. No hammerhead cables? Weren't the cables the crappiest part of those bindings anyway? How about hard wires pivoting on master links?

    Comment


    • #3
      Jason,
      Great work, again. Using the Axl back - to - front: no that is lateral thinking, never occurred to me. Look forward to seeing the real thing. I
      have Axls and Hammerheads. For now I am not touching the Axls for now, but the Hammerhead is looking good, and a simple conversion.
      In its most simple form, the metal toe piece is removed. The Tech Toe is screwed onto the HH base (strengthened with epoxy fill in the voids). I am making alloy plates to hold the guides (rather than cutting the heavy steel toe piece), these will have only two holes for moving the guides. The position of the guides is about 50mm from the TT pins in HH position 5, so a bit short from what others have reported. I have cut the base to allow a little further back, say 60mm. I will try this out first and see if enough. Next option is to mount the TT at the front of the base and move the base back one fixing screw position (going back on an existing ski), this gives a set back of about 85mm, hopefully I will not have to do this, it does not look so tidy, and needs more fixings to the ski.
      What is the set back distance you are using?

      Comment


      • #4
        Brilliant! When I look at that I wonder how possible it would be to shorten the cables, maybe attach them to a flexible plate, and create a front throw that hooks them to the second heel on the boot. People will say I'm just re-inventing NTN hahaha! Nevertheless, I am thoroughly enjoying my TTS kit and want to thank you and many others for posting all your collective experiences with TTS on this forum.

        Comment


        • #5
          Originally posted by cesare View Post
          Brilliant! When I look at that I wonder how possible it would be to shorten the cables, maybe attach them to a flexible plate, and create a front throw that hooks them to the second heel on the boot. People will say I'm just re-inventing NTN hahaha!
          HEY! That was MY idea!!!

          ain't no turn like tele!

          Comment


          • #6
            Impressive. And I also started to think about duckbutts when I saw the drawings...

            Comment


            • #7
              Originally posted by Dostie View Post
              HEY! That was MY idea!!!
              You're already in the history books for inventing the term "earn your turns".

              And now you want more?!

              Comment


              • #8
                thanks all for the feedback.

                yoyo,
                chains, never considered using chains. For this, i don't think they would work due to wreaking havoc on the "cable" guides. But for a design where the "cable" didn't slide on the guide, they could totally work. I have to keep chains in mind for future problems.

                telemarkmark,
                the HH thing. i considered exactly that, but didn't do it for two reasons. One is i don't have a HH to start with, and two, is my goal was to make something that someone else could make, and the HH is no longer available. So went a route where the parts were still available, and would be for some time. I was mistaken about HH cable though. That said, assuming a tech toe can be mounted to the HH shim or a new shim made, and the cable guides don't pop out, it would work just fine, actually great. only issues i see are the obvious 4 holes/radical toes only as the 5th hole for verticals goes right thru the spring (see last years thread and look close on my single spring design, and i designed a clever 3d printed stainless steel bracket to support the 5th hole via screws where the radical front holes would be). Less obvious is that the HH spring is .75"/19mm diameter, and the dynafit screw spacing is 30mm. the net-net of this is there is JUST enough room to put a nut underneath, but the nut can only be recessed into the toe shim so far or it will hit the spring. see my cross section of my single spring binding. If the shim was made from a tough plastic like polycarb, or even better, long glass fiber filled polycarb, putting binding screw into the shim would be fine, and there is just enough room. So it can be done, but it's tight, so plan accordingly.
                Click image for larger version

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                Cesare,
                I have sort of messed with that a little on a 2x4 using freedom power boxes with front springs and a "destaco" plunger clamp, and it is totally doable, but not the direciton i felt like going this time around. But i have thought about it, and that hook over the duckbutt has to be strong, and is a complex shape. And i really didn't feel like dealing with potential broken spring box type failures. If i was to go that route, i think i would run a continuous cable all the way around the duckbutt so the cable was taking the load, not the hook. And i would run the cable inside a bent tube or a plastic part to help with entry. The other reason i didn't go that way is, well, i like F3's which are lacking a duckbutt. Front throws could work for either heel or duckbutt, and again totally doable, but to contain axl springs front throws would be bulky and large, etc. Something like a super loop front throw, but with much more travel, and ideally not the 2:1 spring ratio pulley system would work well (run the math on the effective spring rates needed, etc). Also harder to make the heel assembly removable. Heel throws are very simple requiring only something to spread cable, like a tube or wire, to aid with entry. So again, just chose not to.

                and i think doing a front throw on the HH wouldn't be too bad, basically replace the names sake HH front cable turn/spring support with some sort of front throw, so combine cesare and telemarkmark, and there you go.

                j

                Comment


                • #9
                  I am using Dynafit Speeds, so 4 holes and no problems, as long as the holes do not overlap the base plate fixing holes.
                  From what I read here, the TTS type set up works best with a longer spring, and probably softer, so the HH set up should work well. Interesting idea to put the tensioning throw at the front the spring hammerhead, a bit tricky as it moves. The heal throw does have limitation, especially with softer springs as the amount of pre-load is limited. A front throw can give as much as is required.

                  Comment


                  • #10
                    Perhaps going old school with front throws...setting pre-tension on these bindings is really smooth.

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                    I actually have been thinking about this set-up as a model for a modern simple lightweight NTN or TTS binding.
                    Last edited by iBjorn; 18th July 2017, 12:58 PM.

                    Comment


                    • #11
                      The front throw and second heel connection would be a good choice/ option as well for this design Jason. I think a shaped duckbutt clamp made from delrin or another suitable plastic with the cable routed through it could work. You could even make a small ramp that would mount to the ski to guide the DB clamp back up on the second heel when you close the throw. It could address NTN and non NTN having both options.

                      Way to keep plugging away on this POLR2pin binding!
                      Function in disaster, finish in style.

                      Comment


                      • #12
                        Front Throw: where is the spring? If in front of the toe piece, it would extend a long way forward, not neat. Below the toe piece (as HH) better, with an extension spring is would be quite simple. Using a compression spring (as HH) is more complicated as the throw would need cables routed to the rear of the spring.
                        Had not thought of the ramp to engage on the duckbutt - great idea. If I was starting from scratch I would try this set up, using the duckbutt is very neat.
                        My HH Tech toe lash up, should be complete this weekend, may even try out on the local dry-slope in Edinburgh.

                        Comment


                        • #13
                          Finally, I have something to contribute here. After documenting all the details of building a good 2-pin tele binding it became clear what the real weakness of any Tele Tech System is. Actually, it was obvious the very first time, over five years ago; the spring travel distance. I expected a better cable system would have been developed and be available commerically by now. Here's my idea for using available parts. Start with 22D's Axl cable system.

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                          You need to create your own cable connection to the ski, but the springs and yoke to clamp on the heel are included with the Axl/Vice system.

                          Click image for larger version

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                          Nothing too technical or complicated here. Aluminum angle stock, 2 piece approx. 2" long. Screws securing it are 30mm apart (width-wise). There are simpler ways of doing this, but I had to abandon the original idea so I'm using some left-over parts and ideas. That's a nylon washer that I used a hack saw and files to fit between the angle stock and the cable pivot bolts. It needs a cover and some reliable measurements. I'll post a parts list after it gets tested on snow.

                          The biggest problem is the threaded cable posts. They should be crimped onto the cable by a much fancier (read: expensive) crimper. Most of the parts were available on McMaster-Carr. Of course.

                          ain't no turn like tele!

                          Comment


                          • #14
                            The biggest problem is the threaded cable posts. They should be crimped onto the cable by a much fancier (read: expensive) crimper.
                            If you are near a sail boat yard, they often have heavy duty crimping gear to attach S/S sail boat stays. I had a boatyard crimp some cables for me when I was building some snow pickets for a climbing trip in Peru..

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                            • #15
                              Can you confirm knee to ski spring travel with that rig? And will the cable bend around that small rod thousands of times without fatiguing in half? Nice, simple rig.

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