My turret mill is a Kondia FV1 of early vintage, now with LinuxCNC.
I have numerous NT30 chucks that all mount without any problems.

Purchased recently a 75 mm boring head and today tried to mount it - without success.
As the head is an Asian import, suspicion naturally fell on it.

But, to my dismay, I have discovered the dogs in the quill are slightly offset.
If a chuck is held up to the dogs, a flashlight easily shows up gaps in the fit.
The gap is on one side of the quill, rotating the chuck 180 degrees in the quill makes no change.
Several chucks tested show the same effect.

Had the dogs out, inspected, measured and swapped.
The problem always comes back to the same side of the quill.

Measurements leads me to believe the nominal dog size is 16 mm, and my dogs are that.

The stock chucks typically measure 16.25 to 16.45 mm in width of the slot.
The import is about 16.1 mm.

So, the odd man out is the new head, and it is impracticable to consider rectification of the quill,

Need suggestions on how to get about 0.1 mm off the sides of the slots in a NT30 chuck.

NT30 Dog Slots compr.JPG

John
Attached Images




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