Serious question, I just found out a 1 micron runout on a tool holder can cause a 0.0005" error at the tip of a 6 inch tool.

Read it in a Sandvik technical paper, blew my mind a bit. How much runout do you guys actually see on your machines?

3 comments

3 Comments

Oh man, I've been down this rabbit hole. On our newer Mazaks I can usually hold under 5 microns at the gauge line with good holders, but throw a 6 inch extended holder on there and you're lucky to see under 15-20 microns total indicator reading at the tip. The real kicker is when you think you've got it dialed, then you tighten the drawbar and everything shifts. I started using a shrink fit holder with a precision collet for critical features, and it cut my scrap rate by like 40 percent. But honestly, if your spindle taper has any nicks or wear, all that measuring is just window dressing lol.

willow_martin2mo ago

Wait, you guys are actually measuring your runout? I just get it close, make a test cut, and swear a lot until the part looks okay. In my experience, if the machine is old, you're probably chasing way more than a micron just in the spindle taper.

elizabeth2202mo ago

Honestly the biggest factor people miss is temperature. That old machine's spindle grows a few thou after lunch and your morning setup is trash.