Review on 🔩 HHIP 3900-5129 ER-4 Collet Block by Arturo Reyes

Nice to look at. Arrived well tapped and oily, no fingerprints or corrosion. The nut fits smoothly, but the roughness of the thread is visible. The inner wall cavity showed unpolished tool marks. Experts speak of a concentricity of less than 0.0005" to 0.0002" for quality holders. I measured 0.0012 inside and outside runout when installed in a 3-jaw tool on my 9x18 Chinese lathe with the best flat set. That's about as much as I can get from my spindle and 3 jaws on any setup. I think this will be enough for use in my home shop. Maybe not for you.