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YOUR JUMPING STILTS => Modifications => Topic started by: Jason on January 03, 2012, 09:30:12 PM
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Ok long time since I have done a Modification walkthrough (no time to spare recently) but finally found a few hours to do this one
Just one warning on this mod, you need to be confident cutting and drilling metal to do this, so if you are bad at DIY leave this one alone as you can render 2 sets of bocks useless if you get it badly wrong or at least need to buy new bits to get them working again
And as usual Projump do not in any way endorse this mod and can except no blame if you mess up your stilts (and neither can I )
A few people have shown an interest in how I fitted Exo springs to Powerskip frames (I assume due to the difference in cost between the springs)
Anyway here it is if you are brave enough to take a hacksaw to your £800 Skip frames :)
I started by taking the Powerskips and Exo's apart to get all the bits I needed
You will need the entire Skip frames except the bits from the underside of the footplate down (it will make sence later)
From the Exo's you will need the spring, hoof and the arm that goes from the center of the spring to the underside of the footplate you might need the top bracket too (not sure if the Exo spring will fit in the Skip bracket as I used the Exo one)
You will need to buy some good quality bolts (8.8 or better)
You will also need to have a couple of bits made (top hat washers to fill the holes in the Skip footplate) so the bolt from the Exo's can fit
You can see them in this picture
The sizes are obvious the smaller diameter needs to be a press fit in the Skip footplate
The hole needs to be a reemed fit for the Exo bolt size and the width of the washer needs to be enough to take up the extra space under the footplate to make the drop link a snug fit
All the other sizes are whatever you wantand make no real difference
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Ok now you have the bits here is how to fit them
First debur the inside of the hole in the footplate to clear any chamfer on the washers
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You can then press the washers into place with a clamp using a bit of bearing lock to make sure they stay there
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Sorry about the pics having a shine on them but you can get the idea of how the drop link fits on
And yes I did cut the extra bolt length off once they were finished :Cbiggrin:
You will need longer bolts the same diameter as the Exo ones get 8.8 ones (high tensile steel ) they are easy to buy from a good hardware store or online
I used allen headed bolts as I had them in stock but Hex head will do just as well
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Now comes the brave bit :Cbiggrin:
You have to cut a lump off of your Skip uprights and drill a new hole to take the lower bolt
Here are a few pics that explain it better than words can but all you are doing is raising the back of the footplate to make it level again to fit the Exo spring length
The first pic is of one drilled and cut upright and one uncut but drilled upright showing the original hole and the new one
The easy way to do this is to drill the new hole so that you are left with the same width as the hole between it and the lightening hole above (Look at the pic it will make sence I hope)
Then bolt it to the footplate and mark along the bottom to get your cut line
The other two are after the cut
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Next you have to rebuild your stilts and shorten the side bars (They will need bending in a different place so they fit)
Once you have rebent the threaded rods you will need to level the footplate and cut the ends off the rods
I add an extra couple of nuts and cut close to the last one to get the right length them file them to remove the sharp edges and clean the thread
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The top bearings are the same on both types as you can see on the top picture but I did find that my springs were a bit thicker and fouled the back of the upright even though I used the Exo brackets
This may be due to them being high weight springs so if you are lighter you may not have a problem but I think the holes are set a bit forward on the skips
I cured this by filing away the back of the upright untill they cleared as shown in the second and third pictures
Do go carefully with this as you want to remove as little as possible so file a small amount and keep trial fitting the spring to check
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I replaced the bump stops on the skip with a piece of reinforced hose (from a car spares shop)
The first pic shows how it is just slit to push over the bar
The second pic show the position it is in during use
I thought about tiewrapping it on but it doesn't seem to move in use so I left it alone (up to you what you decide)
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That is it apart from putting the whole thing back together
With the earlier types (Powerskip/PJ/Poweriser/etc) you had to lean forward a bit to get your ballance and they tended to propel you forward as the hoof was set forward
This may be why a lot of people tilted the toe of the footplate down which will move the hoof back under you and bring you more upright
The Exo's have the hoof set further back giving a feeling that you want to stand upright or lean a bit back to ballance which makes it easier to stay still when bouncing and once you get used to it I find better
I found that the finished Skip/Exo Hybrids were somewhere between the two type as far as ballance is concerned and the springs seem to react well to the moving footplate
One thing I did notice recently was that it was easier to go back to fixed footplates from the Hybrids
I broke a spring at the start of a meet and was able to adapt very quickly to the old style fixed foot (it was either that or walk the rest of the meet)
I tried to swap from Skips to fixed once a year or so back and gave up as I hated the feeling so much I swaped back within an hour but this time I was comfy in 10 mins
As usual it is at your own risk if you try this mod and you must be willing to cut your precious Skips up to do it
I found the Skip/Exo's to be the best stilts I have used but they were designed around what I wanted so it was to be expected :Claugh:
If you are tired of paying £300 a set for springs and have a bit of DIY expeience (or better workshop time) then it is an easy way to get 3 and a half sets of springs for the price of one skip set
And at last don't they look good :)
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I would love to hear your comments on this mod and feel free to point out any errors omisions and spelling mistakes you find so I can correct them
So what do you all think
Jason :Hoofies2: :CGEEK:
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as a DIY enthousiast i think it's really well done. congrats!
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Thanks Birt
I love doing things like this but don't get much time
Working on an easily made walking foot at the moment for people that can't afford skips but want to try it
Jason :Hoofies2: :CGEEK:
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Must say iv seen these in action and there awesome,and every part was done to perfection :Cnotworthy:
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Jason, just out of interest do you do any calculations when you do these mods? New stresses/strains etc. I keep meaning to model a set of stilts and work it all out, but never seem to get round to it! As always though great mod, and I can't wait to have a cheeky go on them, if you are feeling generous! :)
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Thanks Clive but they won't be perfect until I can get as much height in a straddle as you do :Claugh:
Tim you know that you can always have a go on any of my stilts (you always make them look better than I do :Cbiggrin: )
I work on the assumption that Bock and all the other guys that have copied his design have got it fairly right
Then I change things slightly to see if it improves the feeling and performance (for me)
I do use all the best materials I can buy at a reasonable cost (I avoid titanium and the exotic mag aloys due to cost)
So the answer is probably no to the maths side of things as it would be covering old ground
Sometimes the maths says very unlikely and the real world alows you to get away with it
I mean work out the maths of doing a double rotation flip and the chances will be low for the average human but add a trampoline and the odds rush skywards I could probably do it with enough practic :Claugh:
If you get round to doing a model I would love to see the results as it might lead to some really good mods and changing the angles of some of the working parts is a lot easier on a model that in real life
Jason :Hoofies2: :CGEEK:
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great thread! wish there were as many bokkers here in the states as over there!
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hey chocl8 if you want a go why dont you join us one sunday on our meets and that way your be able to keep a few of the on lookers happy when they keep asking jason and i to flip :Ctwitcy: :Cwink: long time no see hey tim :Straddle5:
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Awesome, I've always had the feeling that they would be over engineered to pretty high safety factors, but then I've never had a chance to talk to Herr Boeck! If I get it done I'll post it up for people to have a look at, it'l most likely be in Pro E, which isn't the most flexible of programs, but oh well!
@ Clive, It would be great to see you guys again! Do you still Bock on Sundays? I've actually started driving down south about once a month recently, I'd love to meet up again soon :).
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Tell us what sunday you are here Tim and we will do our best to get a meet together
May only be 3 of us but who cares :Cbiggrin:
Seriously though we have a couple of new guys that are keen and Bio has shown an interest in getting back into bocking so if you get down here I can give them all a text and see happens
Jason :Hoofies2: :CGEEK:
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Ohhhhh yes be really good to see you tim ..look fwd to this like jason said just let us know all the best clive :Straddle5:
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Sounds good guys, looking forwards to it! :)