How to design a perfectly-meshing Hirth joint/coupling (That can actually be manufactured!)

[@erniemathews5085]

As a biker born in 1942 when the strongest roller and ball bearing crankshafts had Hirth joints this is fascinating, almost magical.

[@jaxes88]

Not sure what happened at 2:57 to 3:04. Looks like you clicked Use and all the sudden got a triangle? Then once you get to the circular pattern step you never show how to select the loft as the entity to pattern...

[@roberthays6964]

This was very helpful and neat. Thank you! At 2:02, you create the line going up at the midpoint of the hypotenuse of the triangle. This will be where your future plane is at to create the second triangle that you then loft between. Why do you choose the midpoint of the hypotenuse? I ask because my original body that I revolved has more top surface area (less of a hole in the middle). So, choosing the midpoint actually isn't going to cut all the ways through when I loft between the two triangles. I am thinking that I need to create my triangle closer to the origin instead of at the midpoint of that hypotenuse. But I am wondering if there was a specific reason that you did it this way that would mean I shouldn't do that ... and maybe I should instead widen the center hole. I like the smaller center hole because it will give more binding surface area between the two couplings. Thank you for your input!

[@leavoa]

Hi Robert, Happy to hear you found the video useful! There is no special reason to choose that midpoint, it was merely a convenient way to have the sketch become "fully defined" without dimensioning the distance to the center. Let me know how it goes, I'd be happy to hear you made it work and to see the end result.

[@roberthays6964]

@@leavoa it went well, thank you! I will try to upload the file of where it is at right now.

[@strawburrymilk496]

ive got both triangles at 100 degrees but i can only fit 39 teeth. its not clear what you did at 3:11. i think thats where it went wrong

[@Kediil]

Couldn't find a decent tutorial to do this anywhere but here. Really wish it had spoken instructions, or at least hover the mouse longer so I can see what you're selecting. But I managed, half way through blind luck, to figure it out. Doesn't help that I was using Fusion360, but it got done!

[@leavoa]

Happy to hear. Editing this video was an interesting experience since it showed me just how difficult it is to create the quality content we get on KZbin for free. Thanks for the notes, I'll take them into consideration if I ever make another video.

[@dannyortiz8409]

Is it critical to have the inner and outer triangles to be parallel to each other?

[@dannyortiz8409]

Also, do you happen to have any reference or calculations to figure out the number of teeth per angle?

[@leavoa]

@@dannyortiz8409 Not sure about the parallelism question. You can try it out yourself and see. Number of teeth is up to you. If you want sixty teeth, make sure each triangle takes up (360/60)=6 degrees. And use six degrees in the circular pattern (or sixty instances)

[@danielhigh3260]

Hello would you be interested is selling hirth joint ? What you have made is what I want

[@leavoa]

Hi Daniel, do you mean the CAD file, or the physical object?

[@danielhigh3260]

@@leavoa the physical object about the size of a half dollar or maybe a quarter

[@leavoa]

@@danielhigh3260 I don't sell these, but the folks over at www.hirth-joint.com/ seem to. (No relation to them)

[@DJMadMaarten]

Nice! Could you maybe give me the .STEP of this?

[@leavoa]

Sure thing: cad.onshape.com/documents/00e8776cc73eafe9e9a21abb/w/dc812d2316c7834a92890f6b/e/551d20a4c3254e399c137764

[@beardedamerican8929]

I love and hate this video. You jump around so much that it's hard to follow. Then when I copy what you do to start the circular pattern, my loft gets erased and you don't show how you grab the loft, saying it's complete when it's not. How do you grab the loft when it wants you to grab an entity? A loft isn't an entity.

[@jaxes88]

I had the same problem. How I got around it was to use the triangle in sketch 5 and extruded it outwards beyond the edge of the circular joint, extruded as "new" not "add" so that it creates a separate part that you can select as an entity on the circular pattern function. On the circular pattern where you are removing the entity you are copying it will remove the extruded triangle you just created too. You will need to set your instance count for the number of teeth that you want. Hope this helps!

[@beardedamerican8929]

@@jaxes88 lol, you described everything I did. Thank you, the really helps! Knowing that I did it right is good to know. So, yes, absolutely helps, lol