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Balanced Tools G6.3 vs G2.5

Djstorm100

Cast Iron
Joined
Jul 26, 2014
Location
Richmond
What is the true difference in these besides RPM?

If a machine has max spindle rpm of 15,000. I'll tend to buy tooling that's rated to 25k rpm. I guess my logic (although flawed) is more of a "safety margin" by going with the G2.5 balance vs G6.3. I mostly use ER collets, side lock and a few heat shrink. Which all are G2.5 rated to 25,000rpm. I understand with all these, they are balance with out the nut, no tool, etc.

Having said all that, does it really matter which you go with as long you don't get near or over the spec rpm? (20k and 25K in this example)
 
Ehh there can be many variables in how this works.

How big are your tools diameters? Bigger tools at higher RPMs need to be better balanaced to maintain integrity of the system. If you have a big tool in a moderately well balanced toolholder spinning at 10K and a big tool in a really well balanced toolholder spinning at 10K, the better balancing is going to improve the whole system - bearings will wear slower, drawbar will last longer, better harmonics, etc etc. Now you may think "thats such a small amount of difference how could it ever matter?" And youd be right if we are talking just that one tool, but you never run just one tool. You run 50 tools for 10-20 hours per day, so all of that is going to add up. In theory anyways. I could be totally wrong.

IMO buy the best tools you can afford. If you can afford a $100 Shars, buy that. If you can afford an $800 Haimer hydraulic, buy that. I have a $130 Shars shrink fit curved nose holder that I LOVE because it has the curvature for a fraction of the price of an MST holder. Its decently balanced, but I wouldn't run the thing on a Grob or Hermle machine.

At the end of the day I don't think it truly matters that much, but someone with better knowledge of this topic may offer some insight.

And if youre really worried about this, you can buy a balancing machine and balance your own tooling systems.
 
Ehh there can be many variables in how this works.

How big are your tools diameters? Bigger tools at higher RPMs need to be better balanaced to maintain integrity of the system. If you have a big tool in a moderately well balanced toolholder spinning at 10K and a big tool in a really well balanced toolholder spinning at 10K, the better balancing is going to improve the whole system - bearings will wear slower, drawbar will last longer, better harmonics, etc etc. Now you may think "thats such a small amount of difference how could it ever matter?" And youd be right if we are talking just that one tool, but you never run just one tool. You run 50 tools for 10-20 hours per day, so all of that is going to add up. In theory anyways. I could be totally wrong.

IMO buy the best tools you can afford. If you can afford a $100 Shars, buy that. If you can afford an $800 Haimer hydraulic, buy that. I have a $130 Shars shrink fit curved nose holder that I LOVE because it has the curvature for a fraction of the price of an MST holder. Its decently balanced, but I wouldn't run the thing on a Grob or Hermle machine.

At the end of the day I don't think it truly matters that much, but someone with better knowledge of this topic may offer some insight.

And if youre really worried about this, you can buy a balancing machine and balance your own tooling systems.


Thanks for the wealth of info. Do you run the Shars at 12k or more?
 
What is the true difference in these besides RPM?

If a machine has max spindle rpm of 15,000. I'll tend to buy tooling that's rated to 25k rpm. I guess my logic (although flawed) is more of a "safety margin" by going with the G2.5 balance vs G6.3. I mostly use ER collets, side lock and a few heat shrink. Which all are G2.5 rated to 25,000rpm. I understand with all these, they are balance with out the nut, no tool, etc.

Having said all that, does it really matter which you go with as long you don't get near or over the spec rpm? (20k and 25K in this example)

G-6.3 is the general rule for running machine tools except grinders. G-2.5 is better, going better than that the expense goes up fast. Attaching some stuff for general reference.

Good luck,
Matt
 

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G-6.3 is the general rule for running machine tools except grinders. G-2.5 is better, going better than that the expense goes up fast. Attaching some stuff for general reference.

Good luck,
Matt

I am buying in a new CNC mill for work and was looking for information on the ratings difference and came across these pages.

I am considering G6.3 for our cnc mill - a small machine, VMTCNC XH7122 (tormach 1100 in comparison?) machine BT30 and numerous ER collet holders.
The stuff we make is more for in-house use, plates and square rigging bits, and is not an engineering industry -we make animated films, So i would be using it to make mounting plates and fixtures. The machine has a spindle feed of 8000rpm so a long way way from the top 15000 rating at G6.3. My understanding on tool balancing is limited, apart from reading several articles from manufacturers and magazines, forums and pages like this, but the knowledge i have is telling me that running tooling at 8k rpm in a G6.3 @15K spindle shouldn't cause issues for us. We will not be having a balancing tool machine that's for sure, and the largest cutters we would run is 12mm or 50mm face mill.

Would getting some G2.5 tooling be an idea for running smaller cutters - 2mm?
Currently were using my own cnc mill, a converted boxford VMC260 with a 2k spindle! so this step up is a bit bigger for me!
I think im just trying to find out if G6.3 would be fine for our use now as were not actually a manufacturer of parts, just making in house. If it was not ok to use then why would they make them?

The supplier of the machine has suggested G2.5 is better for ATC machines, would this be an issue if i use the 6.3 in the ATC?
 
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