Milling speeds

Hukshawn said:
It's a carbide.
And thanks for the tables.

Of course I know how to google, but there are soooo I many references out there. I, myself, have references I like regarding other things that I suggest to people because I trust and like the reference. So, I assume other people have the same. So, I ask...
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Some the reasons the data is not consistent from chart to chart is determined by the size and type of machine tool, rigidity of the machine tool, rigidity of your setup, spindle horsepower, type of cutter, cutter material, coating, number of flutes, and so on, and so on. For example, Company A may suggest running their 1" diameter 5 flute TAIN coated end mill at 3600 rpm and .006" per tooth feed rate. That may work just fine on a Haas machining center with a 30 HP spindle but it doesn't work on a small bench top mill. I'm pointing this out not to be a smart a** but to point out that the charts don't always apply to our machines. They are a starting point.

My intent is not to offend anyone. My apologies in advance if I did.

Tom S.
 
A quick and dirty calculation I was taught in school eons ago was cutting speed (in SFPM) X 4 / Diameter (in inches) = RPM. It swaps Pi for for 3 and gives it to the margin. This works for turning and milling both.

Careful with running up a flycutter to high spindle speeds. Ballistic tool bits are a worry, and there is an imbalanced spindle load to consider.
 
TomS said:
My intent is not to offend anyone. My apologies in advance if I did.

Tom S.
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No need to worry. Just explaining my motive.
The starting point is what I'm looking for. I couldn't ask for specific as you're right, absolutely everything is a variable.
 
I made up these sheets some years ago. They give starting points for most of what I do. Seems to work in my shop.
 

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  • Lathe Spindle Speeds.pdf
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  • Mill Cutting Speeds.pdf
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When you look up the speeds on a chart especially for material like AL it will almost always be way over the speed that we can get with hobby equipment.
Just tells you that you can go all the way up your speed range if you want to. Adjust to get the best finish for your equipment.
 
Remember that these feeds and speeds the manufacture publishes are only guide lines. Speeds and feeds will work for their cutters under ideal conditions on ridgid machines with good quality cutting fluids. Home shops don't usually constitute ideal conditions and the feeds and speeds must be adjusted accordingly. A good deal,of experimentation is required to get the most out of your machine and tooling I would recommend starting with about 75% of the recommended cutting speeds for a given tool and work your feeds up slowly, that way you can find the sweet spot without damaging your tools or machine. Keep your own records on what works for you and your machining time will be much more rewarding.
 
So far it's all just aluminum. And it seems to be very forgiving.
I suppose a good starting ground to not ruin anything
 
I have this hand written chart on the wall near my mill, it just gives me the ball park RPM but it has worked for me:
The four most commonly used material in my shop is;
MS= 100 SFPM
AL= 250
Brass=300
Cast Iron=60
Tool steel=70
Then
4 X SFPM divided by Dia. of the tool= RPM
Example: I use Aluminum often(with 1/2" roughing end mill) so 4 x 250 divided by 0.500(1/2" end mill)=2000 RPM
I know it may look too simplistic but for a hobbyist working with a mini mill, is alright.
 
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