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Machining annealed 440 steel.

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Airpirate

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#1
I have a block of 440 annealed steel that I want to make some items from.
I have an Atlas MFC mill and wondered if anyone has any experience working this material on and Atlas and has any precautions or helpful suggestions?
 

T Bredehoft

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#2
Is your steel perhaps 4140? I find 4140 a good machining steel. It is not dead soft by any means, not like 11L14 at all, it's nominally "half hard", but can be cut with HSS tooling, just figure a surface feed of 50 feet per minute or less and your tools will survive to cut another day.
 

Wreck™Wreck

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#3
440 is a stainless alloy that is hardenable and is often used for knife blades. I have limited experience with it but it machines fairly well when fully annealed. It appears that a final hardness of 58 Rc may be achieved.
 

Airpirate

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#4
Is your steel perhaps 4140? I find 4140 a good machining steel. It is not dead soft by any means, not like 11L14 at all, it's nominally "half hard", but can be cut with HSS tooling, just figure a surface feed of 50 feet per minute or less and your tools will survive to cut another day.
You are correct it is 4140 and thanks for the information.
 

4gsr

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#5
It'll give you little Atlas mill the run for it's money. Should cut just fine. Mist coolant would help keep things cool and extend the life of your cutting tools. It's cuts slow, not like cutting aluminum. You'll be okay cutting it.
 

Airpirate

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#6
It'll give you little Atlas mill the run for it's money. Should cut just fine. Mist coolant would help keep things cool and extend the life of your cutting tools. It's cuts slow, not like cutting aluminum. You'll be okay cutting it.
My current setup has a one inch cutting arbor with a Morris taper held in place with a draw in bar. I also have a arbor driver that screws in place on the spindle where a check would go. my question is whether the Morris taper and draw in bar would be sufficient for cutting 4140 or should I use the arbor driver which pins into the end of my arbor. the reason I ask is when mounted with a driver the arm is extended so far that the arm support bar covers the Y axis dial.
 

4gsr

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#7
How about posting a picture of your setup and the cutter you are planing to use?
 
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