What do you call the part or mechanism that would help me do

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>>1148206
Like this, But with a blade instead of a top?

>>1148225
Pretty much.

>>1148206
some hand drills are like that, just push to turn instead of crank

>>1148230
Is it called a camming screw or something? What's the name of the mechanism.

>>1148206
It uses a very steep screw, i.e. low threads per length. By pushing it down, two pins (or bearings) pushed against the valleys or whatever of the screw are torqued and pull their housing round with them in angular motion.

Can I achieve this with a variable pitch helix screw?

The pitch starts low to mostly cause pushing out and then gets steep to mostly twist.

>>1148266
pics

>>1148449
See the OP.

>>1148581
Well your post >>1148266 makes it sound like you have a particular screw in mind, instead of a rod drawn on a piece of paper.

>>1148686
I want to design a screw that would do this.

Try googling "yankee screwdriver with a blade."

>>1148695
And cast it? Mock it up on s-ketchup first. You'll want high torque at the beginning, so almost vertical threads, and as you push down more and more horizontal threads need to engage. Honestly this isn't a terribly diy friendly project, because you'll need either some proper bearings and custom housings for them, or some sort of very well lubricated pins. Keeping all that lube inside the mechanism might be tough.

>>1148898
I'm using Inventor. It doesn't need to bear any load. It just needs to push out about 1cm and then spin an arbitrary amount.

It's a part for something else.

I'm sure if I 3d printed it it would do the job, though ultimately it would need to be made out of at least some kind of polymer.

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>>1148959
You could try using some sort of plastic 2-part resin, probably polyester over epoxy, and for that a 3D printed part would make a great mould. But the mould would probably have to be made from silicone, so you'd have to print the part a little oversize and sand it down since you won't be able to sand down the mould's interior. I'm not sure if thermoplastics would be strong enough to replace the thermoset resin, and whether their melting point would be low enough not to destroy the mould could also be an issue.

1cm is pretty tiny, and any threads on this would be fairly brittle. I guess you'll just have to keep prototyping screws until you find something that works. At such a scale you should be fine using a fixed pitch like in >>1148225, but you really won't get much rotation at all unless you use a really fat screw. I think. At least practice with varying thicknesses as well as thread pitches.

Whats the minimum and maximum "push" travel?
How far does the other part need to spin?
Much torque required?; does it push something?
About how big is it?

>>1149082
>>1148959
Also 3D filament is a polymer.

>>1149082
OK, so it needs to push out 1cm, no more, maybe a little less.

The spin needs to be not much, minimum of half a cm max about 10cm.

It pushes a part that weighs a few grams max. The length of the blade is 3.8cm.

From the top of the push button to the back of the blade is also 3.8cm.

>>1149220
What is the blade in this context, and why are you measuring rotation as distance/linear displacement instead of angle/angular displacement?

>>1149264

The blade is a catch that needs to move backwards out of another part and then rotate enough so that it cannot go back into to the other part.

I'm measuring it that way because there's just not much need for precision there. 15º of rotation is probably enough to keep it from going back in.

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You could cam the end of cylinders
-Fix shaft to "outer" cylinder, one next to blade spins on shaft
-Put a spring between them, and a stop "1cm" behind the blade, so it doesn't spin until it hits the stop
-Add some tabs somewhere to limit it's movement, and a spring to return to original position when button is released