Question regarding 'best endmill'.

[g-codeguy]

I am a lathe programmer. Never tested endmills before. I have a job that mills a hex in 303 SS. Original program was milling with the side of a 5/8 inch endmill. Collets are 25ER. Machine is a Daewoo MS200. Not a rigid set-up if you aren't familiar with the machine. You can take a 6 inch piece of brass about 1 to 1-1/4 inch diameter, and tap the holder all over the place. Once on center, I lock both adjustment screws down.

Finish isn't the best looking using the side of the tool. Since flat isn't too wide, I switched to a 3/8 inch endmill cutting from the side using the endmill's flat. In order to keep the cycle time the same, I had to increase feedrate to 30 IPM. Endmills had sharp corners. These corners got ate up pretty fast. I had to drop down to 25 ipm as a compromise between tool life and cycle time.

I ordered ones with .030R corners for testing. My experience with inserts tells me these endmills should hold up longer. They are 4-flute uncoated from Fullerton. Job was setup again about a week-and-a-half ago. Far as I know this job has been running with the same tool since setup. Unfortunately I forgot to look at it last week to see how it was holding up. Operators will run a tool until it fails.

On vacation this coming week, so last week I was swamped with programming for next week. I will borrow the wife's cell phone (hate them myself ), and have the tool checked Monday.

My question is "What would be the best endmill given these parameters?" This is a repeat job. One where the quantities are getting larger. Being a job shop, seconds are important. I need a tool that will run fast AND hold up well.

Thanks.

Dale