First off, why are Misumi's lead screw nuts so expensive?
But the main question; are resin lead screw nuts reliable? They're siginficantly cheaper, but I still want the job done well.
Many use them to satisfaction. I think the biggest problem with these plastic nuts is, they're not suitable for high rotation speeds, because they warm up much faster and melt much earlier than ones made of brass. Luckily, most printer designs do not require high rotation speeds.
