Hey guys anybody have a source for affordable linear actuators? Thinking of replicating Arneson surface drives, should be able to steer with 1/4 scale servo,but I am worried about how to adjust trim? any small actuators i've seen are $800.00 too much for me!!



Thanks Matt



Dare to be different!

Can you build them yourself?
Let me threorize here...

Take a servo and open it up.
Remove the stop from the servo output gear. The gear should now be able to spin 360 degres, this won't work if there is a partial gear in the servo).
Drill out the hole in the gear that drives the potentiometer. Do not drill it thru, just remove the tabs that lock potentiometer shaft in the gear.

Plug in the servo and turn on your transmitter, center the transmitter control you want to use.
The servo will probably be running continuously.
Center the servo by turning the potentiometer until the servo stops running.

Now you should be able to make the servo turn continuously either way by moving the contol on the transmitter, and then stopping the servo by recentering the control. (these could be just buttons for full throw)

If you are satisfied that the servo is behaving consistently the put a small drop of super glue on the potentiometer shaft to lock it in place.
Re assemble the servo.

Glue a threaded rod into the servo output, build a suitable chassis, attach a nut, or blind nut to the control arm of the object you want to move, and voila, linear actuator. $15 dollar servo.

Did any of that make sense at all?

Hey thats one heck of an idea! Yep it makes perfect sense,will try it w/old servo and let you know how it works!


Thanks Matt



Have you tried this? or just an idea?

I modify servos this way to run really small models.
Servo motor/speed controls are great for those little 1-72nd scale Lindberg tug boats,
1-700 scale battleships, and 1-72nd scale tank mods.[8D]

No reason why you can't use it as a linear actuator.

Well Umi I modded the servo like you said and it works good,but it tends to creep,You think I just need better quality radio gear? Using old fp-s28 servo and futaba magnum radio for testing. Will buy new for the project. What about digital servo's? haven't tried one yet. By the way with 4-40 screw attached has a ton of power on nut! Thanks for the help, time to get machining the drives!


Thanks again Matt

The "creep" might just be because of worn contacts in the servo's potentiometer, or even in the transmitter. I have an old ACE AM Nautical commander, an if I shake it, you can watch the rudder move on the boats.[:'(]

Need to spend some money on an FM set up some day.

good luck with the actuator.
Let us see how it comes out.[8D]

Aimee