This is a Linear actuator design I'm using in my robotics projects.
I've created an assembly tutorial on YouTube: https://youtu.be/grQYZmOEgX4
It works using a DC motor to rotate a M4 bolt, which in turn winds a nut back and forth and is in two motor size versions.
Considering the cost of professional linear actuators being far too expensive for the hobby market, I thought I'd put together a variant of the nut running on a thread style actuator.
Since a lot of the non-printable components I've used can be bought in bulk, the per unit cost of these is a lot lower. However, you are getting a drop in quality.
That said, these do provide a nice entry-level into using linear actuators.
The 3 volt motor version is okay, but a bit under-powered for my tastes. The 12 volt version rockets through everything, but will require a beefier power system.
3 Volt Motors
3mm steel ball bearings
M4 50mm bolts
Amazon Affiliate links (I get a bit of advertising money when people click on these)
12 Volt motors
Box of M3 Nylon nets & bolts
If you find good use out of these, please consider clicking on the support button on my profile: https://www.myminifactory.com/users/andrewforster
Thank you and happy actuating!