Open Throw 2 - modern responsive yo-yo spec

Open Throw 2.0 modern responsive spec

Open source yo-yo platform

OpenThrow is an open standard for 3d printing high quality yo-yos. Print the Runabout model or use the hub and self sealing stem bolt to design your own!

Why Open Throw?

The Open Throw project originally aimed to be the best, easiest, and lowest-cost way to create a 3d printed yo-yo. Open Throw 2 adds to this with several new improvements:
 

1. Connection - probably the single biggest change in OT2 besides additional playstyle support is the “Self Sealing Stem Bolt”. This part replaces the acorn nut used in v1. This new component consists of a 3d printed “handle” part and an M4 self-clinching rivet nut (M3 support coming in OT2-extended). These are very affordable parts that can be bought on amazon. The ones used in the model are sold out, but checking the dimensions of these, you should be able to find other compatible ones.
2. Hub - The new hub is larger than the old hub. This is to support more variabilty in the gap as well as allow for commercial non-printed axle systems. Three sizes of hub are available to start: +1mm +2mm +3mm which are named for how much wider they make the yo-yo.
3. Part retention - don't you hate when you take apart your yo-yo and all the pieces go flying all over the place? The new design has "clips" that the stem bolts snap into that keep them in place and aligned. The hub is also a tight fit part now. To help with this, the half is made with a spoked design so you can poke the hub out with a thin rod like a screwdriver. This is in Bambu Studio as a seperate part so that it can be easily printed with a stronger material if you choose. The model shown for the assembly is printed with PLA-CF.
4. Print Orientation and supports - OT2 prints “outside edge” up. This greatly reduces the need for support material and makes the cup look much nicer. The print profile included uses petg support interface which makes removing the support for the hub recess very easy.
5. Weight distribution - The runabout uses a similar weight distrobution to the Synestia 2

Assembly + Parts

Non printed parts: 

•  C size bearing (responsive or unresponsive) Either type of C-sized bearing will work with any OT2 hub. While this file doesn't include Synestia 2, all the hubs will be the same, there won't be any need to reprint hubs for unresponsive bearings of the same diameter.
• M4 20mm, 25mm, or 30mm axle the default hub is designed to work with the 20mm axle for maximum overlap with OT1, however, OT2 will mostly be designed around the 25mm and 30mm lengths. 20mm is as close as you can get to account for the full width of the stem bolts + the yo-yo + default hub gap.
• 2 19mm response discs
• 2 Self-Clinching rivet nuts
   

Self Sealing Stem Bolt
The Self Sealing Stem Bolt recess is a very tight fit and the teeth should bite into the handle. You should use something that can press either an arbor press (or similar, recommended), or a hammer (don't hit it too hard)

FAQ

What if my axle is too short or too long?

If the axle is too long or short, you can print a longer or shorter hub to match. You need at least a 20mm axle for the default width.

What if I want to use the hub in my own yo-yo?

Make a recess that is diameter 24.9mm  and depth 2.82264mm and a thru hole 4.5mm

What bearing sizes will be supported?

C-size, A-size (2a spec), and D-size (extended spec)