Give me the Skinny on End Mills

Peter Atwood

Peter Atwood

Joined
Oct 26, 2000
Messages
2,468
I look at the MSC catalog and I am totally befuddled. There are about 50 pages of endmills listed. I have no idea what to buy....here's what I'm doing:

Mostly stainless steels- S30V, 440C and also 6AL4V titanium. Maybe some 3V in there too.

What specific endmills should I buy for milling 3/8" plunge cuts in stainless? Carbide? How about side cuts? Also, what speeds to run them at?

How about for ti? I would be doing pocket cuts for leaf springs and also decorative cuts at a 45 degree angle.

What I'm really looking for is for someone to say buy #xyz123-45 end mills for this and something else for the other application. I need some sort of starting point.

Any help would be MUCHO appreciated! :)
 
Peter, what I use are 4 Flute, HS, single end, centercutting end mills. Stock #s are like 01890128 for 3/16", 01891326 for 1/2" etc.
Now that series works great for most steels, including 416, nickle silver etc., plus they are inexpensive.
Now for Ti., that I really don't know.:D

Edited to add; All the knife steeels that I use are Stainless Steel. 440C, ATS34, BG42, and the like. Guard materials are 416SS, with Nickle Silver used occasionally.
 
Peter, I think you would be best off going with the carbide 4 flute mills right off. The high speed steel (HSS) works fine for softer materials including mild steel but the exotic blade steels you are useing will burn them up even with the coolant running. The speed on a carbide can be turned up very high, so high in fact that it is not uncommon to see the chips turn blue from heat. Coolant is not advised with carbide as they can shatter. The feed rate should be adjusted fairly slow to keep from snapping them off. They are kind of brittle. Im no expert but have burned up a couple hundred dallars worth of cheap end mills. I bought some really nice new carbides on ebay for less than a new elcheapo HSS.
 
Watch the carbide. Today I snapped a dremmel carbide cutter making a guard slot. Last week I snapped a carbide drill bit. Touchy little buggers. First time I looked through MSC for end mills my eyes glazed over....:D
 
Peter,
I think you will find that the answer to this question is like asking a knifemaker what grinding belts work best.
I use carbide high helix end mills more than others when working Ti and stainless. They work well in pocket milling and edge cuts.
Mostly depends on the machine you are using, feed rate, and speed.
 
A good general rule of thumb:

Use 4 flute carbide emc's on Ti, and on any steel that may be hardened.

Use 4 flute HSS on mild steel, brass, ect.

Use 2 flute, HSS on aluminum, with high feed rates. Works well on brass, too.

You can run coolant on carbide emc's, but you MUST use flood coolant, and keep the coolant on the end mill constantly.
Bruce is correct, though, about running them without coolant, but it is VERY IMPORTANT that you have a blue or black colored chip. This indicates that the chip is carrying the heat away from your work, and not letting the work, or the end mill, get too hot.

Carbide emc's are tough & wear resistant, but highly fragile. They cannot tolerate thermal shock, nor can they tolerate vibration, or shock of any kind. When side milling, you must gradually feed the mill into the work, and keep the depth of cut to a minimum to begin with. I recommend a few light paases, versus a heavy, single pass. This will minimize the shock to the emc, and keep it in decent shape.
Plunge milling with carbide requires high speed, but gradual feed until the full end length is engaged in the material.

I hope this helps. Any questions, let me know. I grind machine tools as a side job, so I'm familiar with them.
 
Thank you VERY much for the info guys! I think you'll save me a world of aggravation and wasted bits. :)
 
Are you guys really cutting plunge lines with milling machines??

I've got one but have been plunging all my blades on the belt grinder.

RL
 
Roger, I can't speak for anyone else, but I sure as heck DON'T use a milling machine to cut plunge lines. I use the belt grinder.
I might use the mill to true up the guard stops, but that's about all, on the blade.
Most of what I use one for is milling guard slots, flattening/routing a mortise in handle material. Stuff like that.
 
Yeh, that's about what I,ve been doing. You know, rough out bolsters, drill tang holes, dove tail; stuff like that.

Seems like the grind comes with feel and experience. I like it and will like it a lot better when I get a good belt grinder. However, I'll listen to and consider ideas that are different.

RL
 
rlinger, when I said plungecuts I was referring to using an endmill like a drill bit and removing material with a downward stroke....just wanted to clarify that I wasn't meaning to mill the plunge lines. :)
 
Peter,
If you would like some machining lessons using your milling machine, let me know. I'll be glad to help any way I can. You would be amazed at the things you can do with a milling machine. I hope you also invested in some good parallels? Going to Indian George's on sat?
Chuck
 
Chuck, I'll be there. Maybe we can check out IG's new micromill and you can give me some pointers. :)
 
No Problem Peter, I just hope that George has some tooling. I'm planning on making another window frame so maybe i'll use it at the hammer-in. I also nee dto turn down an arbor in his lathe.
See you sat.
Chuck
 
Thanks for that. I was getting concerned. Just about the time I was trying to save up for a descent grinder here comes someone talking about plunge cuts with a mill. Very sorry about the misunderstanding and also relieved. I think I got what you mean now. Good!

Roger
 
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