6061 + Carbid Help

@ErichKeane - After reading your overview on grinding it sounds simply enough to give it a try. I'm going to order some blanks and give it a try. Its something I'm going to have to learn anyways. The pre-ground tooling you referenced looks reasonably priced so I can practice with those.

@DAT510 - Yes, all the inserts are CCMT. For the ISCAR CCGT 2-1-AS what speed/feed are you running when your turning ALU? May be worth a try and see how it performs. I appreciate the close-up of the insert.

Thank you to all for the comments and suggestions. There is so much to learn but I guess we all started at where I am today. I'll keep at it!
 
ISCAR calls out SFM from 985 to 3280 sfm. On my lathe, given the part dia. and my lathe's max RPM, I was barely getting 800 sfm. That said I was still getting a near mirror finish, with a feed rate ~0.0025/rev.

The "1" (CCGT 2-1 AS) in the insert nomenclature refers to the nose radius. With the CCGT 2-1 AS, having the largest available in the "2" (CCGT 2-1 AS) size. The larger the nose radius (for any cutter Carbide or HSS) typically will give you a better surface finish as compared to a smaller nose radius, though your depth of cut may need to be reduced.
 
I use carbide inserts to cut aluminum all the time. For me, the nose radius is the most important factor to getting a decent surface finish. I use the largest radius available for the holders I use, and that's sufficient for my current needs. However, the finish I get on many types of steel with the same cutters just sucks. Steel is more difficult, finish-wise, and that's where HSS tools work better for me. I use a relatively lightweight lathe -- a fully manual (and relatively unmodified) benchtop 7x12 -- so YMMV, depending on your machine and how well it's adjusted.

I've used my carbide-insert boring bar on my lathe to make friction-fit bearing pockets in T6061, taking cuts far less than .001" with no problem. Based on my experience, it is possible with the right inserts. My main problem was with the wispy swarf getting into the innards of my 4-jaw lathe chuck, jamming it up. I had to take the whole thing apart to clean it out. Not totally bad, though, It had to happen sometime :).
 
From the appearence, your carbide inserts seem to be of the right kind for Aluminium, ie, sharper edge + larger rake angle when compared with those from Shars. In case not, you will need to get the right insert.

Is it possible that the tip of the insert is not centered ?
 
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