RPC has moved! These pages have been kept for historical purposes

Primary and Secondary tools both have different potential outcomes for your synth. Some synths will give you a bonus to how many you make if you use a secondary tool or primary, usually it makes sense as well. Making lumber with a saw can HQ bonus lumber, since a saw is obvious for doing something like that. They also factor into when making an item if you HQ+1/+2/+3 it. I use my secondary tool when it seems obvious I would use it, awl for making boots as leatherworker, saw for making lumber and masks, etc etc.