Where to find actuators

[CoilKid]

I have a project requiring an actuator of some sort. (Linear actuator, solenoid, even car door lock.) The requirements are that it must be under $20, have a 1" (25mm) stroke, can run on 12V and <2A, and be able to move either 450g(pull) or 20g(push).

I have spent about 5 hours looking around to no real effect. If anyone knows of something that fits these requirements, I'd be very appreciative if you shared. Please excuse me if this seems slightly rude, I have been extremely busy. TIA to anyone who helps.

[Melt-O-Tronic]

It would be easier to help you if you fill in your location information in your profile (at least country & state/province).  I'm assuming you're in the U.S., so you can try SurplusCenter.com (http://www.surpluscenter.com/Electrical/Linear-Actuators/DC-Linear-Actuators/?page_no=1&fq=ATR_Voltage:12\+Volt\+DC).

eBay would be a decent source too since you mentioned automotive door lock actuators as an option.  I once walked into a Chevrolet dealer and asked for their cheapest door lock actuator and walked out with one for a Corsica for around $20.  It worked for years to remotely open my tool box.

[liquibyte]

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2196748_-1

[SL4P]

RC servos - many sizes
Central locking motor - many types
Linear actuators - many types

[CoilKid]

@liquidbyte Thanks, that may work! I am looking for something with a 1" stroke though.
@Melt-O-Tronic The main problem with power door locks, is that the 15 something I've looked at all have 18-19mm stroke, and I need a 1" stroke. 

[calexanian]

One of the guys here came in with some car door lock actuators he got on amazon. Like 2 for 35 bucks or something like that. they were yellow with grey accordion boots on them. Fun to play with.

[liquibyte]

The only other one I found that had that travel was 24V.  You could always restrict the travel by grooving the shaft and putting an e-ring on it.  Easy to do without much in the way of tools too.  Make a slight groove around the shaft at the correct place by hand with a hacksaw blade and then put the shaft in a variable drill and rotate it slowly finishing out the groove to the correct depth.  I actually just grooved two shafts this same way a couple of weeks ago.

[CoilKid]

@liquibyte Well, if you can link the 24V one I might be able to change my current design based on the actuator specs. I don't believe I need to restrict the travel though. I can only find power car lock actuators that have a travel of about 18-19mm since I need a travel of about 25mm, restricting the travel won't be the problem. :-/

[liquibyte]

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2201818_-1

Nominal voltage: 24VDC
Coil resistance: 57.6 ohm (±10%)
Power rating: 10W
Holding force: 4 lbs.
Stroke: 1.0 inch
Continuous
Size: 3.3"L x 1.0"Dia.
Weight: 0.39 lbs.

[CoilKid]

Oh, right. Sorry, thought you were talking about car door actuators. Yeah, that one might work. I'll look into it and try to see if I can design around it. Thanks!

[CoilKid]

Going to take me a while to see if it will work. In the meantime, does anyone know of a car door lock actuator with a stroke of 1"or 25mm? I feel like that might be easiest to use.

[CoilKid]

@Liquibyte Just realized. I don't think the linked solenoid would work, unless I put a spring on it. I need it to be spring loaded out to 25mm, or push type and spring loaded to return to 0mm extension.

[sacherjj]

Electric door lock activators that I have pulled apart are just a small electric motor with a gear that runs on a rack.  This goes to each end and torque limits.  I was seeing if this would work for one application, but I needed holding power.  When you keep power on, it wound up smoking the motor.  Only made for momentary usages.

Motor, limit switches, nut and acme threaded rod.  Cheap, home made linear actuator.  I've used this for a few projects.  Just use a cheap geared down DC motor. 

[CoilKid]

@sacherjj I have no gears though. :-/

[liquibyte]

I've been looking around for you but am having a hard time finding a push pull at 25mm that isn't over $50.  If you get inventive, a washer, a longer roll pin, and a spring would do the trick, especially with the longer one so you have compression room and still get 1" travel.  I've even been down alibaba and as close as I can get is this and still no spring.

[sacherjj]

@sacherjj I have no gears though. :-/

Just buy a geared motor.  Depending on what your exact application is, you might be able to add a nut to a geared motor for electric car seats like this style:

http://www.allelectronics.com/make-a-store/item/dcm-563/12vdc-right-angle-gear-head-motor-with-worm-drive/1.html

[CoilKid]

@Liquibyte Well, thanks for looking around. I'm thinking I'm going to have to build a solenoid system myself using a bolt and spare magnet wire. I was hoping to find something pre-assembled, but I doubt that there's anything out there. Thanks for all the help! :-)
@sacherjj I was looking for a car door lock or solenoid because the actuate quickly. My exact application is moving a dowel rod faster than I could by hand, several times per second. (not continuous)

[Alex Eisenhut]

Hobby stuff can get you soooo close

https://www.hobbyking.com/hobbyking/store/__34839__Turnigy_Servoless_Actuator_for_Gear_Door_90_120_size_.html

maybe you can search along those lines

[CoilKid]

So if I build a solenoid from scratch to do this, I'm going to need a spring. I don't suppose anyone could direct be to an online store selling springs of various sizes?

[sacherjj]

So if I build a solenoid from scratch to do this, I'm going to need a spring. I don't suppose anyone could direct be to an online store selling springs of various sizes?

If you have the space on the far side, it is easiest to tune a pull spring rather than a compression spring.  I would pick up an assortment like this:

http://www.amazon.com/Neiko-Steel-Spring-Shop-Assortment/dp/B000K7M36W/ref=sr_1_1?ie=UTF8&qid=1411611043&sr=8-1&keywords=springs

If you need fast activation, then solenoid looks like your best bet.  Pneumatic is also possible, but outside of your cost guidelines.

[Alex Eisenhut]

So if I build a solenoid from scratch to do this, I'm going to need a spring. I don't suppose anyone could direct be to an online store selling springs of various sizes?

http://www.mcmaster.com/#

But it seems really unlikely that you have such a unique application that no solution exists.

Sounds like you really need a cam.