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What quality are CNC spindles balanced to?

William Payne

Aluminum
Joined
May 29, 2016
I’ve been reading up on spindle balancing out of curiosity and interest. I know that many tool holders are balanced to G2.5 but what about the spindle itself? Are they G2.5 as well or are they G1 or G0.4?
 

mhajicek

Titanium
Joined
May 11, 2017
Location
Minneapolis, MN, USA
I’ve been reading up on spindle balancing out of curiosity and interest. I know that many tool holders are balanced to G2.5 but what about the spindle itself? Are they G2.5 as well or are they G1 or G0.4?

That's going to depend on your spindle; it's like asking "How fast does a car go?" Mine is just like butter at 50,000RPM.
 

William Payne

Aluminum
Joined
May 29, 2016
That's going to depend on your spindle; it's like asking "How fast does a car go?" Mine is just like butter at 50,000RPM.

You are correct but could you tell me what ISO standard it’s balanced to. That seems to be what I’m struggling to find is the quality standard for certain RPM’s.
 

Matt_Maguire

Stainless
Joined
Oct 17, 2011
Location
West-Central Illinois, USA
That depends, most motors and spindles for turning, boring and milling are G 6.3. Then good toolholders & tooling are G 2.5 ASSEMBLED! Then G 1 & G 0.4 are the real nit-picky stuff.

I’ll attach some chit…

Good luck,

On edit I forgot a visual panel where the G#s live vis amplitude, velocity & acceleration… :rolleyes5:
 

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William Payne

Aluminum
Joined
May 29, 2016
That depends, most motors and spindles for turning, boring and milling are G 6.3. Then good toolholders & tooling are G 2.5 ASSEMBLED! Then G 1 & G 0.4 are the real nit-picky stuff.

I’ll attach some chit…

Good luck,

On edit I forgot a visual panel where the G#s live vis amplitude, velocity & acceleration… :rolleyes5:

That documentation is great!!! Where did you get that from? Is it a book?
 

mottrhed

Plastic
Joined
Sep 23, 2013
Location
nh
Ya most spindle rebuilders are at G.4 overall for most modern spindles, but there are certainly exceptions depending on the application and original design. Actual physical imbalance is just ONE of the many things that any competent rebuilder should be concerned with when reviewing the vibration analysis once the spindle is being tested.
 








 
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