Spindle Speeds

[Kitwn]

Good point to check the required spindle power for a planned operation. As well as checking the spindle motor is powerful enough, it's often worth checking how much or little of its capability you are making use of.

Lots of Youtube warriors seem scared to get anywhere near what their machines can achieve and have little idea where that is because they never check. My larger machine has "only" 3kW but when you see what 3kW can do, it can be quite a revelation. If you experiment and go a little too far, what do you have to lose? Cutters aren't expensive and underwear can be washed.

There are a few free f&s apps beyond the fswizard that include spindle power estimates. And many VFDs can display the actual load as a % of max.

I once read a forum entry somewhere that suggested the way to set your feedrate was to increase it until the tool breaks then back off 10% and replace the tool. I prefer to use HSMAdvisor but it's a worthy experiment if you have a handful of 3-6mm tools you're willing to sacrifice. I'm not sure I'd deliberately push my machine that hard with anything larger. Make your own mind up depending on what you have.

Regarding the strength of DIY machines, you're better reducing the depth of cut or tool engagement more than the feedrate if you're getting inaccurate cuts since the cause of smoke, as Dean implies, is not moving the tool through the material fast enough. This leads to rubbing, localised heating and smoke.