Newbie- Spindle Speed

[ngwanhoe]

I notice that the mini milling machine can change gears.

Spindle speed: Low range 0-1100rpm /- 10%. High range: 0-2500rpm /- 10%.

I know that drilling hard material or large drill bits use low speed and soft material or smaller bits can use high speed.

But why need to change gear as the high gear range is 0-2500rpm?

Confuse.....

[Torsten]

As with all electronic variable Speed setups you will loose Horsepower as you slow the motor down. This can stall the motor as you try to put some load on it.
A mechanical gear setup will allow the motor to run closer to its rated rpm where it can supply the horsepower as stated on the nameplate of the motor.
So when running slow the lower gear will give much more power to drive your tool.
Of course some tools do not require much power and will run fine even with the higher gear setup.

[ngwanhoe]

Thanks Torsten,

Ah... I understand a little bit now. That means if I were to drill a large hole with larger drill bits, the low gear provide more torque and would not jam and stalled in the hole.

Cheers