Home/Limit switch sanity check

So, I'm adding home switches to my sherline mill (connected to their supplied cnc driver board). There are pinouts for the parallel port pins I need (11,12,13) on the board but I wanted to do a sanity check before wiring it to power. I am planning on using 4.7Kohm pull-up resistors using the +5 and gnd wires off the floppy disk cable. Am I making a grounding or power draw error here? The parallel port pulls ground out of the PSU anyway (in theory), but I've made errors about such things in the past, so I thought I'd get a quick thumbs up/thumbs down before blue smoke comes out of my PC, rather than my usual method of asking what happened and why.

Hi

This describes the procedure and possible 5v sources. I have used the 5v from a USB socket before, rather than a 5v winding from the PSU itself, which is probably capable of many amps.

www.ahmetozkurt.net/comporg/ekonomi/hw2006/selen2/inputpin.htm

Obviously it is safest to test via an optoisolated circuit, but I have no idea what Sherline provide, they are not used much over here.

regards