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

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oskar

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#1
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
 

Buffalo21

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#2
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.
 

GunsOfNavarone

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#3
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
 

Technical Ted

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#4
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
 

T Bredehoft

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#5
You'll either get to know the feel of a good cut, or break a lot of end mills.
 

benmychree

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#6
Tha
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
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.
 

P. Waller

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#7
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.
 

oskar

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#8

oskar

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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
 

mikey

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#10
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.
 

stupoty

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#11
He always complained the end mills were crap, because they died a quick death.
yeah I wonder why that was ?

Who can tell ?

;-)
 

MrWhoopee

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#12
Calculating chip load and IPM is for CNC machines. I never saw a manual machinist try to calculate it or care to. Dial the power feed down low and engage. Gradually increase the feed until it feels/sounds about right, stopping just shy of breaking the endmill. For all of the science in machining, it's still an art.
 

Buffalo21

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#13
My free Niagara speed and feed slide rule, arrived at the shop, last week.
 

oskar

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#14
Calculating chip load and IPM is for CNC machines. I never saw a manual machinist try to calculate it or care to. Dial the power feed down low and engage. Gradually increase the feed until it feels/sounds about right, stopping just shy of breaking the endmill. For all of the science in machining, it's still an art.
That’s absolutely true, you need to be a good artist to be able to translate what the sound of you machine is telling you when machining.

Nicolas
 

GunsOfNavarone

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#15
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.
Sadly, owning a small machine shop in my garage hasn't magically made me a machinist. I'm working hard at it, but there us no substitute for experience. The slide rule has made me comfortable taking bigger bites than I was previously. I'd swap my little slide rule for one if you all to fly out and show me the ropes, but until then, this stuff is a bit intimidating to us noobs!
 

GunsOfNavarone

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#16
Tha

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.
I bought a super beautiful one from 1941....I'll have to post some pictures...vintage wash machine green plastic(?) Bakelite (?)
 

oskar

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#17
Sadly, owning a small machine shop in my garage hasn't magically made me a machinist. I'm working hard at it, but there us no substitute for experience. The slide rule has made me comfortable taking bigger bites than I was previously. I'd swap my little slide rule for one if you all to fly out and show me the ropes, but until then, this stuff is a bit intimidating to us noobs!
That’s the true! Owning a mill / lathe does not make me a machinist but I try to be by learning and it will take time. Right now I don’t even know how to use accurately enough any measuring tool, lol
 

Mitch Alsup

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#18
You'll either get to know the feel of a good cut, or break a lot of end mills.
This,

Once you develop a bit of feel, you can hear, feel, and often smell; when the speeds and feeds are in the right ball park.
 

GunsOfNavarone

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#19
This,

Once you develop a bit of feel, you can hear, feel, and often smell; when the speeds and feeds are in the right ball park.
I for sure won't break any end mills, but I'll take forever to machine something. I'm super careful and light with the feeds. I'm sure there are negatives to cutting too light, but i feel better too light than too heavy. Working up to the ideal chips, but it is a bit daunting. I would love to have someone with some serious skills show me the ropes...not a lot of machinists in the neighborhood. So what does a quality chip look like from say hot rolled 1018 mild steel? I know my chips are why too small.
 

Doubleeboy

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#20
If you take too light a cut and too small a feed you run the risk of rubbing instead of cutting. Rubbing is a fast way to dull an end mill. Newbies are usually cautious which is good, but too light a cut just plain wears out your tools. Nothing wrong with breaking a few smaller endmills in the pursuit of learning what your machine and you can and can not do.
 

ch2co

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#21
Guns said “I would love to have someone with some serious skills show me the ropes...”

Just ake your time and those skills will become self taught. Learn by doing.

Although I’m still learning I am amazed at how much the process of ‘just doing it’ is a GREAT teacher.
 

GunsOfNavarone

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#22
If you take too light a cut and too small a feed you run the risk of rubbing instead of cutting. Rubbing is a fast way to dull an end mill. Newbies are usually cautious which is good, but too light a cut just plain wears out your tools. Nothing wrong with breaking a few smaller endmills in the pursuit of learning what your machine and you can and can not do.
NO DOUBT I take too light of bites...I'm trying to break that habbit. As i MOSTLY use a 5/8" end mill, i never want to see what that takes to break!
 

MrWhoopee

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#23
NO DOUBT I take too light of bites...I'm trying to break that habbit. As i MOSTLY use a 5/8" end mill, i never want to see what that takes to break!
A larger endmill (1/2 +) is probably a good place to start. You can learn what it will take without much danger of breaking it. Once you have a feel for it, you can try smaller cutters.
 
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