(8 Sept .corrected silly mistake where centre sleeper did not have cut-out in base. )
(see dd revised, DD base has been replaced with the new one.)
This is a simple servo driven points (turnout) motor for G Scale railways.
It uses a standard ES-08 Servo and has a simple Rack and Pinion drive.
It is roughly the same size as the LGB manual points switch, and uses the same screw locations to connect to the points.
Unlike my previous design (http://www.thingiverse.com/thing:349602) this is very small and simple, but does not have the sprung points effect, so trains will derail if trying to "push" against the points. ,
The "Direct Drive Revised" version has the connection to the points at sleepers 1 and 3, which is a better match for some LGB points which are not set up for using sleepers 1 and 2 as in the original file.
The size of the hex hole in the gear was made to be a pushfit on the servo pinion. The two gears in the files have slightly different sizes. I found it best to print a few different sizes and use the best fit. Use the 123D file and modify the hexagon size to adjust to your servos.
The length of the gear is "too long" for the linear slider, but this is to allow the use of a standard 1.7mm by 10 mm screw to hold the gear onto the servo. I found the tiny, short screws supplied with the servo too short for secure fitting of this gear.
A second screw of the same size is used to hold down the lid.
There are three versions of the hex holes pinion in the latest direct drive 123 model, chose the best one to fit your servo.
A small hole in the bottom is there to drain water if it gets in.