Linear actuator with mininum length 20cm and can be extended by 10cm segments.

Non printable parts needed are T8 lead screw with brass nut. https://www.aliexpress.com/item/1005002277808736.html?spm=a2g0o.order_list.0.0.7d801802sy60tu If you have the setup I have - that is 30cm setup, you need +5cm longer lead screw = 35cm. If you would have the actuator without the middle segment, you need 25cm TR8 rod.

Piston is a 15x1mm aluminium tube.

Motor is a standart 370 motor with a gearbox - JGA25-370. https://www.aliexpress.com/item/32987942205.html?spm=a2g0o.order_list.0.0.24e61802fzAk8I Voltage and gearing of the motor and the pitch and lead of the T8 is definitely up to you. I'm using this actuator to open door and window in my greenhouse, I don't need it to be quick. I'm using 150rpm motor with T8 8x2mm. It takes about 30 seconds for the actuator to fully extend. Strenght is good enough, I was not able to stop it holding with my hands, but the actuator is not designed to be super strong. 20T gear is held on the motor shaft by a press fit. If not strong enough, use either glue or insert some aluminium strip from ie. cutting down a beer can to make the press fit tighter.

End stop switches are those in the screenshot of Aliexpress - https://www.aliexpress.com/item/4001283221748.html?spm=a2g0o.order_list.0.0.174b1802hRKIc9 Install them as the last thing, you need to shorten the metal strip of the switch, you can position the swich in the printed body by moving and testing when the switch turns off/on.

Switch diodes need to be anything that can handle 1A and up.

Make the inner piston cube smoother by sanding the edges, use grease on gears, T8 lead screw and the piston cube.

You also need 8 skateboard bearings - classis 608 bearings to support the T8 lead screw.

Motor is held in place with 2 short M3 screws, the rest is 10mm M3 screw. I'm using imbus head screws, use whatever works for you.

All the screws are driven directly to the plastic, do not overtighten, they will hold the parts together sufficiently. I have built 2 actuators and both have been working fine and withstand heavy wind holding door and window in the greenhouse.