What on earth is a conical coupling?

This is a small sub part of finishing off my camera boom, but rather than bury this in that video, I thought I'd break it out into a separate clip as it may be easier to reference for those just interested in it.

[@raymondmarteene7047]

Great tip about the plastic duplicate, I have a use for that.
Cheers.

[@occasionalmachinist]

I've done it, and successfully, but it needs care with heating the steel blank - too hot and the plastic melts out, too cold and it does not form the teeth. If you have an IR contactless thermometer, that could be a great help.

[@stustoys]

If it troubles you, google isn't a fan of the name you used. Hirth coupling gets the nod.

[@occasionalmachinist]

Don't know how you found that. As it's for a camera, I'll call it a Rosette gear (from Wikipedia)

[@paulrayner4514]

interesting 👍

[@guye7763]

You are my main viewing! 🤒 and you are just down the road!

[@occasionalmachinist]

Thanks.

[@paulbyerlee2529]

Do you know the formula based on the diameter and the number of teeth to determine the angle of offset required. I know it's possible to cheat with cad but I'm not familiar with cad software. Thanks.

[@occasionalmachinist]

It takes a bit of geometric thinking, but I work out the circumference of the part and divide by the number of teeth. Because it is a 90 degree tooth, the mid-plane distance between teeth is twice the distance from the mid plane to the bottom of the tooth gullet (or a tooth tip). Knowing that mid plane to bottom gullet distance and the radius, angle= arctan(tooth gullet distance/radius).

[@paulbyerlee2529]

@@occasionalmachinist Thanks for that 👍

[@russelldold4827]

I've seen articles showing these used back-to-back with different pitches to give a low profile discrete movement rotary table. For example, coarse movement one way then fine movement either forward or backwards gives many more discrete movements.

[@occasionalmachinist]

@@russelldold4827 Interesting idea, although sounds like an added complication that most people would not use. Bit like an epicyclic gear box?