Rough edges when milling steel

[Cheeseking]

Honestly the choices and variety of cutter materials coatings and geometry available for specific applications is almost infinite. It will make your head spin.
I have found that McMaster Carr while having a sometimes deserved reputation for being expensive is actually not that bad on end mills.
Its a crapshoot what exact brand you’ll receive but when we order at work We seem to get YG-1 often sometimes meilin (sp?)
Can you save a few bucks on eBay ?sure but buyer beware.

 

[derf]

For smaller end mills I wouldn't even consider HSS for what carbide mills sell for these days.
the-carbide-end-mill-store.com

 

[Janderso]

For smaller end mills I wouldn't even consider HSS for what carbide mills sell for these days.
the-carbide-end-mill-store.com

I would agree until recently I noticed chipped teeth on one of my Rushmore carbide 1/2" 4 flute end mills.
I was surprised to see that. I'll have to be more careful with what I mill. Carbide is awesome but it's also brittle. IMHO

 

[derf]

Carbide is not bomb proof, but given the situation where you don't know what the material is exactly, and speeds and feeds elude you, they hold up a lot better. Even with a chip in one flute, they will cut better than a dull HSS mill. One of the benefits of solid carbide is the rigidity, which will help greatly on a mini mill.

 

[Lo-Fi]

I love carbide end mills, but they really hate recutting chips. That's what usually chips the edges, all other things bring equal. I use one of the cheap misters, but air only and carefully aimed to evacuate the chips immediately, particularly when slotting.

They don't like chatter much either, and one move from a not so rigid setup will spell the end.

If you're mindful of those things, they last a really long time and do some beautiful work at insane speed.

 

[Janderso]

If you're mindful of those things, they last a really long time and do some beautiful work at insane speed

Are you using them on a CNC machine?

 

[higgite]

I have used ME Consultant a freeware feed and speed program for years. . Get’s you in the ballpark.
You can Google and download it.

Cheeseking, I wonder why you get .191 HP but I get .134 HP with the same input data? All other inputs and outputs are identical, including efficiency. The link to the user guide doesn't work on my copy, so maybe I'm overlooking something.

Tom

 

[Cheeseking]

Ya the program has its quirks. There are probably better ones out there but hey its free. I don’t know the answer to why the discrepancy but what I have found is whenever I change a value in one of the boxes, I make sure to click the green box below which updates the values in the other boxes as applicable. Sometimes that has burned me.

 

[Tozguy]

There is not much you can do with a dull end mill no matter how much it cost. Save any dull mills until you can sharpen them even the cheap ones. If you are only cutting a shallow slot, a shorter end mill would have less deflection. When cutting both sides of a slot simultaneously a 3 flute end mill would be a better choice. It would have been interesting to take another pass to widen the slot on one side by climb milling to see if the burrs still occur.

 

[Lo-Fi]

Are you using them on a CNC machine?

No, just on my bridgeport. Takes some cajones to dial the spindle speed up, but when you do they start shredding steel like its butter. 4 flute 8, 10 and 12mm are my go-to carbide tools. All from Rennie or APT. Sorry neither are too helpful for you US guys! Both seem to be decent quality at very reasonable prices. I've got some HSS mills from APT too, for jobs where I know carbide isn't really suited. Very impressed with the 12mm fine pitch rougher, it's an absolute workhorse. I'd recommend HSS roughing ends mills to any newbie - well worth it for general metal removal, they're much more forgiving than either carbide or plain HSS.