Need Servo Motors Bigger than R/C

Have a look through the Trident Engineering product range. It's a UK company, but they have data on several makes of motor available worldwide.

Robot Market Place has a lot of parts, supplies and materials for robots, RC hobbies and general electronics. Their prices are pretty competitive too.

-Adam Doyle

Have you tried looking at the heavy duty r/c model servos designed for plane (and boat) control first? Some of them are substantially more powerful than the ones used in r/c cars (especially the ones designed for the larger scale planes).

For example - 6V 42kg-cm

http://www.gwsus.com/english/product/servo/heavy%20duty.htm

Additionally you can always add some gears or linkages to increase the force at the cost of reduced speed. This works well up to a point, but again it depends on your application.

Are these example servos suitable? What exactly is your application?

Have you looked into using modified wiper motors?
There are several websites that tell how to build them.
www.fieroaddiction.com/servo.html
I think either the July or August issue of PM or PS magazine has an article in it about building one.

Have a look to firgelli.com they have mini servo linear actuators, the model L-16 is stronger. Also you may be interested by trossenrobotics.com and phidgets.com

Like these maybe?

http://www.baldor.com/products/servomotors/r_series/bsm_rseries.asp

You guys are great! I was thinking of using a servo to automate a gear selector, but the Firgelli linear actuators look like a much better solution. They don't require the constant PWM signal like a servo does. Command them once and they do it. Their website has lots of info and tech notes and a forum. I love CR4!

I have lots of positive experience with linear actuators from HSI. Great quality, performance and prices! http://www.haydonkerk.com/

and if you need very large gear reduction ratios in a very small package and very little (virtually zero) backlash, look at Harmonic Drives. I'm aware of only one manufacturer of these gearboxes. Harmonic Drive Systems inc.