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6082 aluminium heat treating, help?

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  • #16
    Just a suggestion.
    Can you get your hands on a tube bender?
    If so try and bend the rear ski posts like so.

    Ji
    Attached Files
    Grip it and Rip it

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    • #17
      the whole point is that there are pivots for the two rear skis so when you lean over both skis will edge. If you are still confused search for north legion smx in images. no shock though, when you say loads do you mean my weight or the forces being applied to the frame.
      Thanks for your help man! I cant even begin to tell you how much I appreciate it!

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      • #18
        Yes I mean your weight including clothes, safety gear, back pack, water........
        Also will you be jumping this thing? if so what height and to a flat landing or to a down ramp?
        Consider this like a design committee and take on board all the ideas, think about them and then make up your mind.

        I have raced motocross since the seventies. The two rear skis look dangerous to me. If you snag a foot it will get ripped back under the frame and could break your ankle. I have done this a few times on my foot pegs and they are designed to fold back.

        The two rear horizontal members transferring the seated load to the ski posts will be in bending moment. They will have to be designed correctly as they will carry load and will deflect. Can you instead make another triangle with its apex at the seat post and the legs going down to the skis on a say 30 degree angle.

        Ji
        Grip it and Rip it

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        • #19
          You lost me in both of the last 2 paragraphs

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          • #20
            Okay I will do a little drawing.

            If you don't keep your feet up your toe can get snagged into a rut and left behind as the bike goes over the top of it. your calf hits the frame and break you get a trip to the doctors.

            It all depends if you will be wearing skis or just boots when you ride this bike.

            Ji
            Grip it and Rip it

            Comment


            • #21
              The triangle transfer sub-frame.

              Ji
              Attached Files
              Grip it and Rip it

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              • #22
                Okay I have now taken a look at that skibike.
                Complicated hip and knee joints.
                And your feet are on the outside of the rear ski posts.

                Ji
                Grip it and Rip it

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                • #23
                  Here is another type
                  http://www.youtube.com/watch?feature...yeRKM3W-o&NR=1
                  Ji
                  Grip it and Rip it

                  Comment


                  • #24
                    Originally posted by Jigantor View Post
                    Yeah, in my portfolio I did research on several ski bikes and that was one of them, I cant believe that the best solution was starring me in the face the entire time! I'll be wearing snowboard boots when I ride it and that sketch you did, would it still be able to edge the skis because I cant see how, it would need another horizontal beam at the top, it could be a lot smaller than the lower one though.

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                    • #25
                      Originally posted by Jigantor View Post
                      Yes I mean your weight including clothes, safety gear, back pack, water........
                      Also will you be jumping this thing? if so what height and to a flat landing or to a down ramp?
                      Ji
                      And I forgot to answer this, I shouldn't weigh more than 70kg with all of my stuff but I'm only 15 so will still grow quite a lot, and yes I am definitely planning on going big on the jumps and I will probably ending up jumping or dropping to flat. I know that everything will eventually break but I want to eliminate the risk of it breaking on me in real world conditions, eg I want it to be built like a tank but weight is still a concern, just secondary to strength. Ideally I would like to order metal tonight, (uk time) school deadlines. Do you think 2-3mm would be ok or should I go thicker?

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                      • #26
                        Before you order anything.
                        Have you worked out dimensions of each member?
                        If so estimate how much this thing is going to weigh including the skis for 2mm and then 3mm.
                        Next check the slopes where you intend using it to see if they will let you on their lift with it.
                        Remember on a lift you will have to hold it for the length of the trip to the top.
                        If they will not let you on than you will have to push/carry this thing to the top.
                        Weight will be a major factor.
                        Not all lift operators will let you on with a hand held bike.

                        The next issue is that pivot swing arm. How ever you are going to do it work them out before ordering. These will be very difficult to get to work perfect the first time. The front of the skis when in the air will tilt down, you have to come up with an idea to make them always stay level or tilt up. Or when you land the bike will nose dive.

                        Big air is not a length. You will have to work out what you think your body can absorb to a flat landing and then use it for the design. Without shocks it won't be much as your ankles/knees will collapse and your men bits will smash on the cross bar.

                        Ji
                        Grip it and Rip it

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                        • #27
                          50x50x3mm SHS aluminium square tube has a mass of 1.52kg/m length.
                          I estimate that there is about 5.45meters of this tube having a net mass of 8.3kgs.
                          The unit still needs handle bars, head stem single or duel front steering arms, rear swing arm pivot hardware, foot pegs, seat and three skis to account for weight wise.

                          The unit will be at least 20 kgs.
                          Are you sure you can carry/handle/hold that all day?
                          And hold on to it on a lift.

                          Work out what all the parts weigh and check my assumptions, then go carry something around that weighs a similar weight. An aluminium 88cf scuba tank weighs around 20kgs and it is not easy to carry more than 20 meters on flat ground.

                          Ji
                          Grip it and Rip it

                          Comment


                          • #28
                            over 20kg!? When I'm over estimating I cant get above 15kg! And anyway, the way I'm doing it is that you go on chairlifts the same way as on the north legion smx and tow lifts should be easy.

                            What did you mean by this?: "The next issue is that pivot swing arm. How ever you are going to do it work them out before ordering. These will be very difficult to get to work perfect the first time. The front of the skis when in the air will tilt down, you have to come up with an idea to make them always stay level or tilt up. Or when you land the bike will nose dive."

                            Just out of interest do you ski or mountain bike or are you just an experienced welder?

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                            • #29
                              I have been snow boarding since 2002.
                              I also mountain bike as training for motocross.

                              Ji
                              Grip it and Rip it

                              Comment


                              • #30
                                Awesome! So what did you mean about this "The next issue is that pivot swing arm. How ever you are going to do it work them out before ordering. These will be very difficult to get to work perfect the first time. The front of the skis when in the air will tilt down, you have to come up with an idea to make them always stay level or tilt up. Or when you land the bike will nose dive.!

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