Typical Depth of Cuts for steel

[Palinvan]

Hi everyone,
I'm pretty new to machining. I bought my Taig DSLS 3000 in March and have only used it for aluminum and wood so far. I would like to start cutting some mild steel and work my way into alloy steels like 4140 and I am wondering what people are generally taking for a depth of cut? If anyone out there can suggest a safe depth of cut of for 1/8" & 1/4" endmills I would greatly appreciate it.

Thank you!

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[allesg]

Depends on feed rate, rpms, cutter diameter, material cutter is made of,
and what you're cutting. HSS cutters make sense for newbies.
Carbide is expensive and breaks but not if you know what you are doing.
There is a formula and a chart for different materials. This is not a table saw!
Find and use the formula! The formula is only an approximation - a starting point.
Machining is not all science despite all the math and formulas. Be one with the machine.
You should have a copy of the machinists handbook and/or a text on machining.
Older machinist handbooks are cheaper and usually just as useful. EBAY!
Recently there has been a short form of the machinists handbook - it's fine.
SAFETY GLASSES & NO LONG SLEEVED LOOSE CLOTHING!
When in doubt, start with shallow cut say .005 NOT .250, start with slow feed.
Use a scrap piece of stock. make a pass. use cutting oil. Use a step over of
about 25% at first. Avoid cutting at the full width of the cutter.
If it doesn't sound/feel horrible try increasing DOC to .010 on the next pass.
then .015 and so on. Repeat until the machine protests!
You should recognize when the machine is protesting then back off.
You should learn when you are feeding too fast or too slow.
You need to learn what sounds and feels good.
You need to learn to read the cut.
It would be very good experience to do this for a range of cutters and materials.

[crob09]

Hi everyone,
I'm pretty new to machining. I bought my Taig DSLS 3000 in March and have only used it for aluminum and wood so far. I would like to start cutting some mild steel and work my way into alloy steels like 4140 and I am wondering what people are generally taking for a depth of cut? If anyone out there can suggest a safe depth of cut of for 1/8" & 1/4" endmills I would greatly appreciate it.

Thank you!

I agree fully with allesg!
A good way to think about the feed rate or cutting speed is to picture yourself with a rotary tool in hand. Just concider that old saying "let the tool do the work for you"
The mill is just like you, it's guiding the cutting bit, not forcing it threw the work. As you know wood is softer than metal, but some wood bits take longer to cut material than others, and just because something will cut metal does not mean it will cut wood.

Cheers,

Rob
what is a cnc

[Palinvan]

Thanks for the tips guys! I now have a good starting point.

[UUU]

You might like to experiment with depth of cut vs step-over amount. I like to cut more using the side of the cutter than the end, so more depth of cut and less stepover.

[bebob1]

If you are doing full face slotting (180 degrees rotation of cutting per tooth), and if you are going by trial and error, try not to go over 10% of the diameter of the cutter for your depth of cut. Also use short stub end mills first and coated whenever possible e.g. TiAlNi coatings. High helix cutter is recommended. You should also know many steels tend to harden when processed under different conditions, including while it is being milled. Generally they say the cutters should take deeper bigger cuts and avoid dwelling when cutting steel to reduce strain and thermally caused surface hardening. This means compared to say what you are used to for aluminum, for the same RPM, the feed needs to be higher, or alternatively for the same feed, the RPM should be lower. Sort of like whats recommended for cutting plastic, except the reasons are different because then youre trying to avoid melting.