Tips for corner rounding end mill?

J

Jeff D.

Aluminum

Joined

Jul 11, 2007

Location

Spanish Fort, AL

• Nov 22, 2008

• #1

I'm just a home hobbiest, and have never used a corner rounding end mill before. I am working on a little project, and want to put a 3/16" radius on some small blocks of 303 stainless. Any tips or suggestions would be appreciated. I'm using a manual Bridgeport, without power feed.

Take it all in one cut?
Straight mill most of the cut, and climb mill the last little bit to get a better finish?
Approximate spindle rpms?
HSS vs carbide cutter?

I don't have a coolant system. Thoughts on using compressed air, or cutting oil?

Thanks in advance.

Jeff

 

J

johncollins

Aluminum

Joined

Jul 7, 2008

Location

Alpine, TX

• Nov 22, 2008

• #2

Corner rounding

HSS mill, look in Machinery's Handbook for speeds and feeds, should be able to do in one pass if your machine is rigid enough, I use a Kool Mist mister an like it (clean up is easy and you don't have a coolant tank to clean once in a while).

John C

 

L

L Vanice

Diamond

Joined

Feb 8, 2006

Location

Fort Wayne, IN

• Nov 22, 2008

• #3

This type of cutter is usually found in HSS, and I don't think I have seen one in carbide except for routing wood. Carbide router bits will do OK on aluminum, but I have never tried one on stainless.

The best tip is to run slow and feed slow. The largest diameter is the one that rules when figuring cutter speed, but don't go to the limit. It is easy to dull these cutters, and if you do, it will require grinding back a lot of face to get back to the unworn part of the edge.

I like Tapmatic Edge stick lubricant for many milling operations and other work. It is not messy like oil and other liquids.

http://www.lpslabs.com/product_pg/cuttingfluids_pg/EdgeLube.html

Larry

 

S

SND

Diamond

Joined

Jan 12, 2003

Location

Canada

• Nov 22, 2008

• #4

Micro100 and others make them in carbide and they cut well. I have also used the basic router bits, in stainless(304/316) and such up to rads of 1/2" or 5/8". Takes a few cuts yes, but its carbide, why would it not cut? just get the one with the 1/2 shanks, though even with the 1/4" shank and smaller cuts a lot can get done. But it may not cut wood or plastics quite as well after wards.

It can be a little hard to get a proper radius done in 1 cut if you only have 1 part to do. I usually rough and then fine tune the height and last depth of cut required to a proper appearance. I usually climb cut the last pass because my mill is tight enough to do it, I don't know if yours is.

 

H

harrytm

Cast Iron

Joined

Jun 18, 2002

Location

Corry,PA,USA

• Nov 22, 2008

• #5

If possible, trim most of the corner with a 45 degree cutter or tilt your part in the vise and flat mill or side mill the corner to leave minimal stock to then clean up and finish with your corner rounding cutter.

I often just keep shifting the part in the vise to mill the resulting corners and kinda "facet" the corner until there's very little to finish with the rounding tool.

 

fmari --MariTool-

Titanium

Joined

Nov 15, 2005

Location

Illinois

• Nov 22, 2008

• #6

I agree it helps if you are doing this manually to rough it out with a 45 deg tool. Also makes the corner rounding endmill last longer which tend to be more expensive than chamfer tools.

I have solid carbide double ended TIALN coated corner rounding endmills on my website if you want to try the carbide route. I would just brush some dark cutting oil on the part and climb mill. 2000 rpms would be a nice conservative number. Should last a while in 303 stainless.

 

J

Jeff D.

Aluminum

Joined

Jul 11, 2007

Location

Spanish Fort, AL

• Nov 22, 2008

• #7

Thanks for all the tips. Very helpful.

fmari --MariTool- said:

I have solid carbide double ended TIALN coated corner rounding endmills on my website if you want to try the carbide route.

Click to expand...

What's that website?

Edit - Didn't realize it was right there in your screen name. $59.30 for a double ended carbide, 1/2" shank with 3/16" radius is looking pretty good compared to other prices I have seen.

 

67Cuda

Banned

Joined

Oct 22, 2008

Location

West Coast, CA

• Nov 23, 2008

• #8

L Vanice said:

I like Tapmatic Edge stick lubricant for many milling operations and other work. It is not messy like oil and other liquids.

http://www.lpslabs.com/product_pg/cuttingfluids_pg/EdgeLube.html

Larry

Click to expand...

Tapmatic Edge stick is good for sawing, but using it for milling is messy, it's a pain to clean off.

 

D

Dictoolsindia

Plastic

Joined

Dec 2, 2020

• Jan 22, 2021

• #9

Hi
Corner Rounding end mills are used for breaking edges and putting a smooth radius on a part. These are suitable for milling deep inside a pocket or on the backside of the part

DIC TOOLS INDIA
Manufacturers of HSS End Mills | Reamers | Drills | Milling Cutters

 

K

kazlx

Hot Rolled

Joined

Nov 22, 2010

Location

Tustin, CA

• Jan 22, 2021

• #10

Another handy method tip, if you are doing edges on a block, set it up for the correct cut off of the fixed jaw, then you can just rotate your block in the vise to hit all the edges, then flip the part and rotate again to hit all the edges. Much easier to get a clean radius if they are all square edges rather than trying to compensate for the nose diameter and turning handles to make sure it all matches.