I've got the cheap enco stuff in 1/2-10 and its about .009 out in one foot - it rusts freely too. Edit; its got some burrs on it to so needs a bit of attention before usig it with a plastic nut.
The McMaster stuff rates between .009 and .003 on thier website. The Precision acme rod on the page Gerry's provided at MSC say's 0.003 /foot but I've replaced the enco with thier 1/2-5 precision and I cant measure any varience over three feet. It's definitely one of the aresa where you get what you pay for.. |