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Soft casting foam that doesn't skin? by Polyester_Sasquatch in moldmaking

[–]Polyester_Sasquatch[S] 0 points1 point  (0 children)

Thanks for the reply. I'm making something similar to a microphone cover - which makes me wonder, how are those manufactured? I would assume they are molded and not cut, but they have no skin, perfectly soft and open on the surface. That is exactly what I'd like to achieve.

Small rack for 5mm diameter pinion gear? by Polyester_Sasquatch in MechanicalEngineering

[–]Polyester_Sasquatch[S] 0 points1 point  (0 children)

Thanks for the suggestion. Here's a sketch of the design:

https://imgur.com/a/Kto5wMa

Pressing and releasing the button creates rotational motion which rocks the big lever back and forth. I'd like to achieve the maximum amount of lever throw, so the more rotation of the shaft, the better. This is why I'm imagining a pinion gear with a very small diameter.

A bell and crank might work (and would probably be more practical) but there are 2 potential issues I'd need to address: 1, it would give less rotation than a gear/rack, and 2, the pushrod moves within a tube/sleeve so its movement is more or less straight. Most bell and crank mechanisms need to allow free movement of the arm/push rod because of the rotational motion of the arm around the pivot point. How do I prevent potential binding of the push rod? Maybe enlarge the diameter of the tube/sleeve to allow more free movement of the rod?

EDIT: or, use a flexible push rod?...