im thinking about doing some upgrades as i fix my k40
how ezy is it to put on a water switch
Flow switch?
Pretty easy if you’ve got an analog machine, just connect it to the laser enable button.
If you have a digital k40 it might be a bit more of a pain. There’s a pin on the board that if you’re lucky they’ve used a jumper, on mine they’d just dumped a bunch of solder on there. :\
Awesome i will order 1 now 
@beny_fits which one is best to order?
I have heard issues with some not being sensitive enough that the flow of these weak pumps does not trigger it?
Unfortunately the switches I’ve ordered off eBay were not sensitive enough. My (dubious) fix was to pull them apart, clip the spring and mount them upside down.