Problem- Insert or no insert

[daytona81]

I can't upload pictures from my iPhone so I'll have to do it at home. But basically I have I 3" 6 flute shell mill the I use only on aluminum and have been isn't it for years with only 5 inserts. The 6th insert spot has a piece chunk missing from the tool itself from before I started working here. The piece missing is directly behind the cutting edge of where the insert would be. It's not huge but there is enough material missing to make me question if it's safe to put the 6th insert in without blowing up the tool. Anyone have an opinion?

[Perfect Circle]

What kind of RPM's will you be running?

[Perfect Circle]

What style and IC insert are you using.
And what type of matl. are you going to cut.
If it is AL. you should be fine. If 1/3 of the backer matl. is gone then I would start to question the stability of the cutter...on anything but soft matl.
If you have any more info I could answer your question better.
You said that you have been running it with 5 inserts for years?
Now why all of a sudden do you want to run 6?...Just asking

[daytona81]

Originally Posted by Perfect Circle What style and IC insert are you using. And what type of matl. are you going to cut. If it is AL. you should be fine. If 1/3 of the backer matl. is gone then I would start to question the stability of the cutter...on anything but soft matl. If you have any more info I could answer your question better. You said that you have been running it with 5 inserts for years? Now why all of a sudden do you want to run 6?...Just asking

I just replaced the inserts and i just got curious as to why we never Put the 6th one in. The only material we cut on our machine is aluminum t6 6061. Rpm range is anywhere from 2500-7500. The range is so big because we've contracted so many Programmers through the years until I started to take over. I'll get some pictures to you later afternoon

[Perfect Circle]

Ok sounds good

[PixMan]

What blows my mind is why would any commercial shop continue to use a damaged tool that can only give 83% of its full capability? Send the thing out and get it fixed. If that's not practical, find a new replacement. If that's still too much money, find a replacement on Ebay.

BTW, just about ANY 6-insert 3" face mill cutting nothing but aluminum should be running right up at 7500rpm all day long. That's not even 5900 sfm, and carbide can cut 6061 at twice that.

[packrat]

Originally Posted by PixMan What blows my mind is why would any commercial shop continue to use a damaged tool that can only give 83% of its full capability?

I can see you never worked in a small jobshop.

[PixMan]

Wrong. During my 30+ years of being a machinist, I've worked in 6 different shops that employed less than 12 machinists. I think that's "Small job shop" by definition.

Only ONE of those shops would have kept using a damaged tool. All others would have bought a new one, and sent the damaged one to one of the growing number of places that'll fix them so they'd have a backup tool when the damaged one was fixed.

It's not that I've never worked in a small job shop, it's just that I don't like to work in a foolishly cheap job shop. Good tooling doesn't cost....it pays!