Chip welding boring operation 1/8" endmill in 1/4" hole in aluminum

I’m struggling to figure out a good feed and speed strategy for boring a 1/4" diameter hole using a 1/8" 102z Carbide 3d endmill in 6061. The total DOC is .45" . I’ve now chip welded 2 endmills because as it gets deeper the whole isn’t clearing. I’ve monkeyed with going faster and going slower. Anyone have any ideas a strategy for this. I’ve got compressed air running but its so tight near the hole it doesn’t seem to help clear once its past .15"

You mean 1/4" #201?

I’d suggest trying it with a #102 or a 3/16" endmill.

You do know that you can remove the aluminum using lye? Easiest way to get it these days is to get a drain cleaner which uses it as the active ingredient.

Sorry I meant the 102z endmill fat fingered it. 1/8" endmill. I’m soaking them in lye tonight to see if it will clear the chips. Still trying to get a strategy together though for how to make these holes.

What milling parameters are you using?


Once you share those, I can advise on which ones to change.

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Ok so honestly I’ve tried so many combos and fiddling not real sure where I’m at currently next to try. I was running the last test at 18000 rpm 30 in/min, I think the pitch was .03 climb cut with lead to center. My next test was to drop it to 10000 rpm , 20 in/min and try a smaller pitch at .01 and i’m down to my last clean 102z bit, before I soak the others in lye.

I would give this a try, as these are my settings for a single flute (that’s what I use typically in aluminum) when boring holes adapted to what you want to try.

Climb cut
RPM = 10,000 (this will help allow for more chip evacuation)
Chipload = 0.001 (20 in/min)
Pitch = 0.5mm (0.02 in)

That should work. You could even share the file you’re working on to make sure nothing else is weird.


Ok that was the direction I was heading. In this case there isn’t anything in the file really but holes for figuring out boring strategies in Aluminum in 1" bar stock. Its sort of my testing process with aluminum so I don’t ruin parts in operations I have proven yet.

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