Need max spindle speeds for metal

[bgolash]

Hi Group

I am working on a spindle design for metal machining.
I was wondering what the high and low spindle rpms
would be required for general machining. I`ve seen the
Bridgeport specs at 0 to 4500 rpms. The high end at
4500 seems high for metal when is this higher speed
required. I will be using a PMDC motor to drive the spindle.
I need to know if I need to gear up or down for
maxium usage. The PMDC motors are avalable in 1725
or 2500 rpms.

Thanks

[ESjaavik]

Originally Posted by bgolash The high end at 4500 seems high for metal when is this higher speed required.

When you use small diameter cutters.
When you use carbide tools.
When you cut aluminum.

With a small diameter carbide cutter in aluminum you might want 45000 rpm!
A good place to ask is where you buy your tools, they can tell you what the best speed and feed is for the cutter and the kind of work you do.

[bgolash]

Thanks ESjaavik
Just the info I needed!

[Mcgyver]

you're going to need to know the theory on this, but the good news is its simple. Then, knowing to what use you will put the machine, you can figure out the speeds you need.

check out http://its.foxvalleytech.com/MachSho...c/SpeedRPM.htm

the big BUT here is those are optimal numbers and our older or lighter duty home shop stuff usually taps out on rigidity and hp before we achieve those speeds. On my XLO (b-port), I rarely get over 3k but there’s been many times when i wanted less than 100.