What's new
What's new

Mandrel Alignment Shimming


Aug 16, 2021

We have 2 Mori Seiki NLX2500 lathes that was crashed a while ago. 2 new employees did it within days of each other. They are fixed with the exception of the mandrels not centered with the spindle. They drove the turret into the barrel with the mandrel engaged. We were able to get one with 0.006" and the other with 0.018". Within operation, the 0.006" reduces down more. The 0.018" has a +/- window of 0.005". We are allowed a 0.012" deviation on concentricity.

We have been using Trial and Error alignment methods for shimming the mandrel. Does anyone know of a formula that will account for the length of the mandrel and the offset of the gauge to determine the thickness of the shims needed? We have 3 different mandrel bases and 3 different sizes for each. We run a dial indicator on the rim and take in the values of the 0, 90, 180, and 270 degree positions. We shim on 2 sides to make for a solid triangle base.

It doesn't take me long to shim a mandrel base within 0.006". However, I am primarily maintenance and manual fabrication. The CNC operators could use some tool to decrease the change over time. I already made shim kits with slots for each size. We make threaded pipes for pumping stations and drilling operations so you have an idea of the application the lathes are used for. Any tools or information is appreciated. Thank you.