How do you Figure out the Feed Rate on Manual Mills?

oskar

oskar

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Just wondering if there is a trick or something to figure out the feed rate (IPM) when you are milling.

To practice I only mill aluminum and I can calculate the spindle RPM but for the feed rate I just go by the sound of the cut and adjust it accordingly.

Nicolas
 
My old boss, you to have his mill set at max (about 2000 rpms) and just turn the power feed up or down until it sound like it wasn’t going to blow apart, regardless of material. He always complained the end mills were crap, because they died a quick death.
 
I just use my best judgement depending on the rigidity of the setup/work piece, machine, tooling, etc.. On my Bridgeport I like to hand feed first to get a good feel for things and then I will set my X feed rate accordingly. If it's a real delicate job I will most likely hand feed it.

Yes, sound and chip formation are two good indicators to use.

Ted
 
Tha
GunsOfNavarone said:
These guys will send you a nice slide rule calculator for free.....I'm hoping to use it enough until i start getting a feel for it....

Free slide rule calculator
Click to expand...
That is a good plan, I've used these speed/feed calculators for over 50 years, they take the guess work out of (especially) milling, good for drilling and lathe work as well.
 
There are no "tricks", if the device that you are using has no defined feed rate you would simply measure it and make note of the actual speed at an indicated speed setting, you are a machinist after all.
Measure, do a bit of math and have at it, you will not be terribly far from what you require this way.
 
So it is based on judgment and good judgment comes with experience. Since I started milling about 3 months ago I only broke one end mill so I guess my judgment is not that bad, lol

My thanks to all

Nicolas
 
When feeding manually, I go by feel. When a tool is cutting right, you can feel a slight resistance to the feed. At this point, the tool is cutting continuously and efficiently. The actual rate varies with the depth of cut, material, tool wear, cutting oil, etc. Power feed is fine and I use it a lot but when I am not sure of the rate, I feed by feel and then try to approximate it with the power feed pot. This applies to end mills, lathe turning tools, parting tools and most other cutting tools that are fed into or along a part. Might give it a try.
 
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