Show Off Your 3d Printed Unicycle Stuff!

That is a neat idea. Do you know what the downsides were?

I have it 10.5mm narrower than “0 Q-factor”. This is leaves about 2mm clearance to my Nimbus Oracle frame. The pod still sticks out a bit from the “0 Q-factor” plane. I would need a thinner/bent frame if I want to make it closer to a “0 Q-factor” position. This is my limiting factor in my opinion now.

Do you know how the Mad4one Agile cranks are 3mm narrower? Are they “bent” inwards"?
This does sound way better than making custom cranks… Pedal threads being about 13mm deep, I also agree maching 5mm off should be fine for road-type riding.

Snapping in half, likely because there was not enough material in the region around the crank interface. (To be fair, those were essentially prototypes where they pushed how light they could make it, the ones where they didn’t push that worked fine)

As far as I know, they are just slimmer on the outside than the normal ISIS standard, this also means that some crank bolts stick out ever so slightly.

I was not aware that there was printing in steel being done,that is amazing. I would have though that models were made, molded then cast in metal. Is this actually printed or are we talking about cnc milling or water jet?

I am really disappointed in the fact that you can’t buy just that bracket or for that matter any of the components individually with the KH system. If one part gets damaged you have to buy the whole thing and they have not been readily available since covid

It is actually 3d printed.
Most of the time it is a metal powder that is melted with a laser. But this is printed in a plastic loaded with a lot of metal particles infused inside, and then cooked to join the metal particles. (You can look for the metal x system by markforged if you want more explanation).

And I have a doubt, I wrote that it was printed in steel, but I think it was actually inconel (a nickel alloy).

And yes, it is really annoying to have to buy a whole system to get those parts.

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I’ve just got myself a snazzy new 3D printer (Bambu Lab X1 Carbon) so I’ve been thinking about printing stuff again lately.

I know nobody’s really had any luck with handles before, but I’m wondering whether 3D printing in nylon, and then wrapping in glass/carbon fibre would give me the required strength for it to be actually useable. Obviously dimensions would have to be a bit smaller to account for the fibre addition, but that’s no big deal to design in.

On the Mad4One ISIS cranks with pins, you stil need a slightly tapered intereface for the pins to slot into. This is typically done with a broach for the overall shape, and then a coining operation to add the taper.
Although at 1º you can maybe get away with this happening when the cranks are fitted?

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Did you add a taper to your design, or accept that for one degree it might be best just letting the axle form that taper as you install the cranks?

You’re making me want to 3D print some cranks now

I see. Some photos of other cranks they have even have a little cone shaped protrusion at the bolt.

How about remelting in salt, as in this video?

Did a quick simulation of Corbin’s handle with 50lb load:


The high z stress (seperating the layers) area is right near where Corbin’s sample broke. 30 MPa is right around the limit for PLA/PETG layer adhesion strength according to CNC Kitchen’s video. However, remelted, it increases nicely to 50MPa.

Yeah, I have the 1º taper.
I initially tried a nominal press fit of 5mm as illustrated in the ISIS standard drawings, but increased it to 6mm. I will try more if these cranks loosen… ISIS standard recommended 3-6mm for aluminum cranks.

I would have thought a 5-axis CNC could make the ISIS with pin holes along with the 1º angle. I assume needing a broach would make it impossible to get a custom one made by a normal machine shop.

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A 5 axis cnc would do that, or a rotary indexer on an angle. I’m not sure which mad4one did, or maybe it even works without the taper if the pins are soft enough, but I’m sure that avoiding the coining operation and associated tooling was the point of using the pins.
Brilliant bit of engineering I think.

Lea Opitz had a 3d printed t bar at unicon, that apparently lasted for over a year now. I only talked to her very briefly, but maybe you can ask her what it’s made of.

I honestly think Corbins design has potential if you add material at the baseplate, not much reason to keep it as thin as the standard handles there I think.

Yes, no need to make it look exactly like an existing seat base handle mount.

I designed mine without the groove for the cover (some saddles don’t require it) for this reason, mine still failed, but my next thought was to get longer bolts to go into the saddle so I could make the base thicker.

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Starting small:


Some brake line clips in PLA (100% infill). I’m curious to see how they hold up, but since I recently got a 3D printer, I did a quick print (<15 minutes overall) of these because I got tired of wasting zipties. A bit tight in the clips and a bit loose on the line, but I can probably make 50 of these for the cost of buying them and improve in future iterations…

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First unicycle specific part:


Since washers don’t really fit on mad4one frames, I decided to make these small spacers, so I can finally not get annoyed with the bearing caps anymore. I printed these at 2.6mm thickness (ended up measuring slightly under that) and can’t feel any play when the bolts are fully tightened down, but the wheel still moves quite freely.

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Get a normal washer, cut away 30% on a side and now you own a mad4one washer! It is easier than you think (it is 30% lighter than a normal washer)

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As the saying goes, “If the only tool you have is a hammer, it is tempting to treat everything as if it were a nail.” Or in my case: “If you have a 3D printer, a 3D printed part is a solution to any problem, if you look at it long enough.”

But here are a few reasons why I went with this over cutting a washer:

  • very easy for me to get the right (and equal) thickness for every washer with very little work (takes 2 minutes to adjust the thickness in CAD and start a new print)
  • No need to buy washers
  • No risk of rust
  • I can now replicate these at the click of a button and give them to others (might even make a few different thicknesses for that purpose)
  • while not strictly necessary, it’s neat that these are the exact shape of the bearing holders
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I usually remove my cranks before flying to UNICON and to reduce the wear on my bag in the spot that my ISIS spline rubs, and cover the spline to reduce dirtying my clothes I 3D printed an ISIS cap that would sit over the spline before being held in place by the crank bolt. It worked for the intended purpose.

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