<p>I'm trying to gear down a servo even further. I notice that the majority of the gears are made of nylon, and I want to create new gears that come close to the resolution and strength of the existing gears. I have a Replicator 2, but the resolution does not seem to come close to what I need. Any suggestions on how I can create nylon or other hard material parts that might work?</p>

I looked at the current Marlin code and the P24 command should work as you expect it unless the pin you are trying to use in listed as the "SENSITIVE_PINS" list:
```
```
#define SENSITIVE_PINS { 0, 1, \
X_STEP_PIN, X_DIR_PIN, X_ENABLE_PIN, X_MIN_PIN, X_MAX_PIN, \
Y_STEP_PIN, Y_DIR_PIN, Y_ENABLE_PIN, Y_MIN_PIN, Y_MAX_PIN, \
Z_STEP_PIN, Z_DIR_PIN, Z_ENABLE_PIN, Z_MIN_PIN, Z_MAX_PIN, Z_MIN_PROBE_PIN, \
PS_ON_PIN, HEATER_BED_PIN, FAN_PIN, FAN1_PIN, FAN2_PIN, CONTROLLER_FAN_PIN, \
_E0_PINS _E1_PINS _E2_PINS _E3_PINS _E4_PINS BED_PINS \
_H0_PINS _H1_PINS _H2_PINS _H3_PINS _H4_PINS \
_X2_PINS _Y2_PINS _Z2_PINS \
X_MS1_PIN, X_MS2_PIN, Y_MS1_PIN, Y_MS2_PIN, Z_MS1_PIN, Z_MS2_PIN \
}
```
```
These pins are printer specific; so, without access to your Marlin build, I can't see if pin 4 corresponds to one of these.  If this is the problem, the command should be returning an error.  If there is no error, I would look closely at the hardware.