Tiny tool feedrates

[Jonathan]

I can wind my poor old mill up to 2000 rpm but I can't say it enjoys it. Ten times that is cloud cuckoo land. The best I can offer in my comfort zone for a long cut is 1200 rpm.

That's interesting...I'm pretty sure we both have the same milling machine (I posted a picture of mine recently in my build log) and I've had mine on the maximum, 2150rpm iirc, for the past few months! So am I damaging the machine, or are the bearings in mine better (it's not overly noisy)?

1mm cutter, how many flutes? If it's 3 flute carbide then I also make it 57mm/min..so yes 1mm/s when cutting a slot. However if you're only taking 0.25mm off then you can up that to 2mm/s (again assuming it's 3 flute) because it's less than half the width of the cutter etc. Still going to take forever...

Where are you getting these small cutters out of interest? Why do you need such a small cutter...it must be a REALLY fine mould?

[Robin Hewitt]

Why do you need such a small cutter...it must be a REALLY fine mould?

Not really, I'm trying to recreate a couple of moulds I already have that are showing signs of wear. I don't want to spark erode 90 degree corners and a 0.5mm radius looks like a credible approximation on the drawings. I can hand grind 0.5 to square if it looks naff but I'd rather not.