Out with the wobbly standard Porter Cable collet Tools and in with the refined, low TIR (Total Indicated Runout) ER collet. If there is a significant runout, then bores will be slightly larger, fine etching grooves will be wider than expected, tiny end mills will break easily, and the router bearings would wear faster. Here is a collet specially made for the Porter Cable routers so you will have pin-point accuracy. These collects are rated at 0.0004″ TIR Precision Grade. Now, you can have the precision at a low cost that is typically found in expensive spindles. This collet wouldn’t be complete without the nut to fasten it on to the router. This nut must be used with these collets.