[partsman]

We are looking at a couple VF-0Es with the 10,000rpm 20HP spindle. I have read quite a few posts about the 20HP actually being substantially less than that at most RPMs. I'm assuming that they get 10,000rpm by changing to a different pulley ratio and that this would reduce torque in all rpms. Do the 10,000rpm spindles have a noticable loss of torque compared to the 7500rpm version? I don't think the VF-0 has a gearbox so how does this effect tapping or making heavy cuts. I'm mainly working in aluminum so the 10K is nice but not if it will prevent us from doing 16-18mm tapping or making heavy roughing cuts. Any comments would be appreciated.

Thanks (again) in advance.

[gizmo_454]

The 10K spindle, based on my readings, should still be a 1 to 1 ratio just like the 7500 rpm spindle.

As to the power/heavy cuts, all I can offer is what I have experience with. We have a VF2SS with the 12K, 30HP spindle. That is 50% more power than what you are looking at, obviously, but this is what I remember off the top of my head....

6061-T6 Aluminum
3/8" 3 flute Helical Solutions reduced neck end mill
10,000 RPM
120 IPM (0.004 IPT)
Radial WOC = Full slot (3/8")
Axial DOC = 0.200"
Spindle Load = roughly 30%

6061-T6 Aluminum
3" Mitsubishi APX3000 9 flute indexable end mill
1500 RPM
27 IPM (0.002 IPT)
Radial WOC = 2"
Axial DOC = 0.020"
Spindle Load = roughly 25-30%

I have not yet loaded any taps in this machine that are any bigger than 3/8". I have, however, tapped up to 1/2-13 in 1018 steel with our Mini Mill. That is a 7.5 HP 6,000 RPM spindle. I don't remember the actual cutting conditions other than we used a spiral point plug tap, it was a through hole about 3/4" deep, and that the spindle load meter was higher than I would really like it to be. Probably in the neighborhood of 70-80%. For that machine, I would say that is probably about the biggest you would want to tap. Over that, I thread mill. In aluminum, you MAY be ok in the 16-18 mm range with the machine you are looking at. I am, however, speculating at this point.

I hope at least some of this info helps give some perspective of where you should be with the machines you are looking at.

Good luck!

Mike

[KenFoulks]

If your biggest concern is threading aluminum on a machine this old, then you have nothing to worry about. Every spindle has lower torque at high rpm, since you won't be tapping at 10k or even 5k; you will be fine.

[partsman]

Thanks again Ken & Mike!

If your biggest concern is threading aluminum on a machine this old

What else SHOULD I be concerned with on a machine this old?

I've only got one shot at this and don't want to pick the wrong machine. I own a message board for old construction equipment and am usually on the other end of these types of "what should I buy" threads

I really appreciate every one's feedback.

[KenFoulks]

You can call the HFO where the machine is or your local HFO and ask for the service history. You can also view the Alarm History on the machine. I would recommend asking the selling party to show you a demo of the machine cutting steel and aluminum. A square boss with a round pocket will tell you almost everything about the machine.