Raymarine ST1000 Tiller Autopilot Limit switch carrier assembly

This is a limit switch carrier that can be added to a Raymarine tiller pilot to prevent the unit from self-destructing in case the motor attempts to drive the unit beyond its physical limits.

It needs to be printed in PETG, HT-PLA or better due to its temperature tolerance. You also need a printer that is well calibrated. The unit should be printed upside down and can use a spot of tree support. A skirt is optional, rafts, brims etc should not normally be required.

Mine was printed at 0.32 layer height and 0.4 width YMMV.

These switches will activate and the diodes connected across their terminals will then only allow the unit to move towards the middle of the stroke until the unit is out of danger.

There is an accompanying youtube video with assembly instructions. My channel is called Sail4life.

More tips and details are on hackaday:
https://hackaday.io/project/192920-tiller-autopilot-limit-switches
 

Note you will also need 2x small microswitches, four m2.5 x 14mm screws with nuts or hot melt inserts and a 1.6mm stainless (welding) wire you can bend to shape yourself. Details are in onshape and below the video. Besideas that it requires some soldering, stranded wire and two Schottky diodes rated 6A or more continuous.

The cap-seal bearing unit can be printed in PETG in case yours was already broken by the impact of the plunger and sled on the end plate.

The source files are located at:

https://cad.onshape.com/documents/ff892cc9957fb0d175a6a223/v/53364b00edf9ea2185319d31/e/4644be35b096e6c55c23fbe9?renderMode=0&uiState=64f3539a4ea89400fd74ee01

The project is titled "ST1000 LimitSwitches" in onshape cad. This is v 1.0.