My 3x3 Recumbent off-road trike

Discussion in 'Other Toys/Hobbies' started by Sam_Q, May 5, 2010.

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  1. Pipster

    Pipster Member

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    This is AWESOME, so jelous of your workshop :D

    The part im most interested in is the making of the hubs, as i intend to make my own in the future.
     
  2. OP
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    Sam_Q

    Sam_Q Member

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    well then would it interest you that while I made the last hub I filmed the whole thing explaining what I was doing step by step?

    I just didn't get around to making it into something
     
  3. OP
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    Sam_Q

    Sam_Q Member

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    Updates have been slow lately because at the moment to do anything meaningful I need some more cro-mo and tooling, unfortunetly I can't afford either right now. That asside I managed to do a little bit of work on a part I already had handy:

    [​IMG]

    This housing will be made so it's half into the crank boom part of the frame and located under my knees. It will hold the shaft with the gear cluster, electric drive freewheel and uni-joints off the ends. I am using the wind in bearing mount off an external bottom bracket intended for a mountain bike. This is just a convenient thing for me for a few reasons.

    A confusing thing though is that I used the left cup as I should and it has a right hand thread. I am looking at it and any bearing drag will try and make the cup unwind, anyone have an idea why they did this? It seems back to front to me.


    Here's the bell end view:

    [​IMG]

    Once again I used an aluminium insert to allow for distortion during welding. For the other end the thread has been cut about 5mm longer than it needs to be so it can be welded in and then milled down to size.
     
  4. Aetherone

    Aetherone Member

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    Its fitting with cycling mechanical tradition dating back to the days of loose balls in a race with cups being held in place with lockrings - where the cup doing itself up would seize the axle and make the bike unridable.
     
  5. OP
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    Sam_Q

    Sam_Q Member

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    oh now it makes sense, so they errored on the side of it falling apart instead of self destruction. Knowing that I would of fitted the right side on the left, not that it's going to make much of a difference with the way I will do it up.
     
  6. Aetherone

    Aetherone Member

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    Yep, easier to retighten by hand every few kilometers to get home than seized and walking. :wired:
     
  7. Quan-Time

    Quan-Time Member

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    riding in spandex is less homosexual than walking in spandex.

    But only by the SMALLEST of amounts.
     
  8. OP
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    Sam_Q

    Sam_Q Member

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    hahaha, would it make you feel better to know the only thing I ride with is denim jeans? so much for being a bike junkie.
     
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    Sam_Q

    Sam_Q Member

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    I made part of the assembly of my electric assist unit. Due to the few perks of my driveline layout I am fitting my e-assist in the middle under my knees, this drasticly simplifies things. I plan on using a brushless motor with a primary toothed belt under-drive, and a secondary reduction via 6.35mm (1/4") chain using parts off pocketbikes. To transmit isolate the motor when not under load I thought I would use another freewheel (#4!!) with an adapter to a 60T pocket bike sprocket originally intended for one of their rear wheels.

    Here's the sprocket I started with read in my lathe chuck below. These don't run true and they where heavy, so this was the first step for fixing both problems.

    [​IMG]

    A very short time after I took this photo I took it back out, cut the inside out with a grinder and then put it back in. While still unpleasant to machine it made it a quick job.



    [​IMG]

    Center machined out and drilled on my rotating table. The larger holes where for the mouting and smaller holes for the weight loss.



    [​IMG]

    An aluminium plate turned down to suit the inside that would be my sprocket carrier.



    [​IMG]

    A view from the other side



    [​IMG]

    Shape contoured, it's very hard to make out but the middle section is recessed 2mm down in the photo, up to a locating ridge and back down again 3mm for the locating ridge.

    The holes where also drilled in for the mounting to the sprocket and also the freewheel, one bolt for each tooth (14).



    After this I took no more photos so here is how it looks finished:

    [​IMG]

    Front view.



    [​IMG]

    Back mount.



    Sprocket mountings:

    [​IMG]



    Freewheel in place on how it's going to sit:

    [​IMG]

    [​IMG]



    For anyone who is curious this took what seemed like a long time to machine.

    I now just need to work out the bolting method from sprocket to carrier, I had in mind crankset bolts but I will see.
     
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    Sam_Q

    Sam_Q Member

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    Forgot to add an update, I machined my center shaft with my splined section for the gear cluster now attached, I really don't know if I did it right but I am going to go with it for now. If I have to I can make something new later.

    [​IMG]

    [​IMG]
     
  11. OP
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    Sam_Q

    Sam_Q Member

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    had a reasonably successfull day:



    [​IMG]

    This is my main crank boom, this was machined out on the mill as a releif for the 8 cog gear cluster.



    [​IMG]

    A plate fitted on top to cover the hole ready for welding. This would of been from the housing of either a washing machine or a dishwasher. I would of liked some cro-mo plate but at this stage I just can't afford any luxuries like that. The pipe is oversized anyway so I can't see a problem.



    [​IMG]

    Welded in place, ground down and then rewelded and ground again.



    [​IMG]

    End of the pipe trimmed, roughly cut before being shaped to suit the cross-boom.



    [​IMG]

    Test fitted to the frame showing how the releif is cut.


    [​IMG]

    How the sprocket cluster will fit.



    This is where I encountered a problem. My mid drive shell has three different outer diameters and I was going to cut two different size recesses in the frame to suit. The first I cut with a tungsten tipped hole saw which worked usually well, however for the larger diameter I didn't have something usuable so I tried to use a boring head but the cutter grabbed the edge of the welded in sheet metal section and peel a part of it up. So I stopped, attempted to clean up the damage and let it be. I have ordered a cheap 44mm hole saw so I can cut the other recess to suit.

    This is how it sits right now:

    [​IMG]

    Later it will be almost flush with the plate to sit in the right position. I also plan on welding on some bracing on either side of it due to it's high position and stress loading on it.
     
  12. Quan-Time

    Quan-Time Member

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    Looking good. Welding is getting better it seems ?
     
  13. OP
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    Sam_Q

    Sam_Q Member

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    this is a bit of an odd one to weld so it can't be rated properly, when it comes to doing the main frame I will need to get my act together. Either that or tach weld it and get my friend to tig weld it.
     
  14. Quan-Time

    Quan-Time Member

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    TIG weld would be the way imo.

    If you have it, try "pulse" weld on your mig. I think its exclusive to 3phase migs tho, so check into it. But its VERY useful for welding things.
     
  15. OP
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    Sam_Q

    Sam_Q Member

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    I definately don't have a pulse mig, those things are expensive. For if I will weld it or get my friend to that I will decide when the time comes, I will likely just weld it myself as the only difference will be that it's a bit neater with a tig.

    In other news I ended up fitting some anodised aluminium chain-ring bolts into my sprocket carrier:

    [​IMG]

    I figure if they sheer in half doing a 3x3 wheelspin then I will just replace them with a steel type.
     
  16. OP
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    Sam_Q

    Sam_Q Member

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    Decided to continue machining on my handlebar clamps. These pivot off the frame and hold onto conventional 31.8mm mountain bike handlebars.

    This is what they looked like when I worked on them last which was quite some time ago:

    [​IMG]

    and after this night:

    [​IMG]

    [​IMG]

    Apart from putting the two main holes in the second clamp I need to now drill, tap and recess for the two pairs of clamping bolts. After this the final shaping such as the radius cuts.
     
  17. OP
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    Sam_Q

    Sam_Q Member

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    Finished my handlebar clamps. I made the silly mistake of boring out the handlebar hole to 32mm instead of 31.8 (1-1/4) however when done it up it takes up the gap easily.

    Pics:

    [​IMG]

    [​IMG]



    and fitted:

    [​IMG]


    Now I know these are quite bulky in their construction however I figure that they will be subject to reasonably strong loads.
     
  18. Quan-Time

    Quan-Time Member

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    Thats not bulky at all. Sure theres a few sharp edges to clean up, but its a great effort.

    As for the 32mm VS 1 1/4" bore size, you generally want it to be a touch over. So 0.1mm per side is actually a nice slide fit. You would not want to go any looser, but thats totally accecptable for steel / alloy pinch system.

    You usually bet on 0.1mm diameter however.

    Get some alfoil from the kitchen. Wrap one clean smooth layer around your handle bar, put a screw driver in your clamp to lightly open it a touch. Slide handle bar and everything in. Do it up tight. Use a knife to cut off the excess.

    You wouldnt even know its there or see it, and it helps prevent scoring into your handle bars, and it provides a nice soft surface to clamp too.
     
  19. OP
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    Sam_Q

    Sam_Q Member

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    I mean bulky as in physically large. If you compare this to the clamp on a mountain bike headstem these two I made are huge, however they arn't too heavy and as I said above they could use the strength.

    I will still take the edges off as you said and also I need to fit a bushing for these. The bushing will be out of Vesconite stock and fit into the 30mm hole to suit the 25mm shaft that I will have going through it.

    You right about the fitment, you see in my previous job I had to make a clamp and I made the fitment a tiny bit loose, it was in steel and had crap all give so it caused a problem. That's why I was concerned at first, I was already thinking of putting strips of a coke can in there. However because of the good deflection this clamps fully and very well. It springs out when undone so it's self ejecting which will be very handy later when I have to trim it to size with multiple test fitments. There will be almost no torsional force on the bar and very little pushing force so I don't think the clamp would be stressed much even if I only had one of the two M6 bolts.

    During this coming day I might have a go shaping and fitting the middle of the cross boom so I can get a crucifix shape like a trike frame is traditionally meant to have.
     
  20. OP
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    Sam_Q

    Sam_Q Member

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    Center section welded in and the first stage of the power shaft completed and in place:

    [​IMG]

    [​IMG]

    Even though I machined a pocket for it the housing ended up being crooked. To fix this I ended up putting a slot in the frame just before the housing to bend and reweld it.

    The middle shaft has two different threads on the left side- M20 x 1.5 R.H and a M22 x 1 Left hand. The empty space between the M22 thread and the bearing will be for a flat section where I can put a spanner on to take it apart. The adapter that uses this thread however will cover it when assembled.

    The M22 thread will be for the drive of my electric assist and the M20 is to power the left side uni-joint. I could not have a shared thread because if they both where on a right hand thread then the torque from electric assist would try and unwind the uni-joint, or alteratively with a shared left hand side thread the uni-joint would undo by itself off the shaft. So to fit the adapter for the electric drive it's slid over the top of the smaller M20 thread and would in backwards on the shaft.

    The right side and the inside of the shaft are not yet finished. This side will be machined to suit a common 1-3/8" bike thread. I am going to have a classic wind on 6-speed freewheel instead of the cassette type cluster due to a design/clearence issues. It means more weight but it's much easier to package, works with my electric assist better and is narrower. I made sure to buy one with ramps on the teeth for smooth changes, all 5 and most 6 speeds just had wind on cogs without profiled teeth.

    The right side uni-joint will be powered by a drive-shaft that fits down the inside of this power shaft via an internal M20x1.5 thread. So all up this component will have two left and two right hand threads on this one part alone. You could say my thread cutting skills have improved.

    I beleive that the way this is going to fit together will look interesting enough to warrant a video, this shaft is going to have all of the following: middle bearing support, sprocket cluster, adapter for e-assist sprocket, outer bearing support inc deraileur mount, cog for rear drive and two uni joints, one them likely using a seperate shaft for power. All of this will be self locking and will come apart easily for maintenance.
     
    Last edited: May 21, 2012

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