I’m trying to tap 7075 aluminum on my 8l. When I get to about.3 inches of depth the motor starts to slow down and then stops. I then have to e-stop and remove the piece of aluminum off the tap using vice grips. I use a 3 flute carbide spiral cut tap for 1/4-20s. I also you cut tap fluid and I have a spindle speed of 350 rpm. I am also able to tap 6061 like butter. Does anybody know why the motor might be slowing down and stopping or if the 8l is capable of tapping a 1/4-20 on 7075?
Try using a peck tapping cycle. I have used pecking successfully in 1045 steel. I was using a 3/8" 2 flute spiral point tap. I was pecking .2" per peck, to a total depth of 1". I was having the same problem you are, stalling my spindle and having to finish by hand tapping the part. I was turning in low range at 350rpm. I also add tapping oil when I switch my tool to the tap. The oil made a big difference. If you use a spiral point, make sure you have plenty of hole depth for the chips to pack into.
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I find 7075 to be gummy “chip weld” to drill and taps. Using real “tap cutting oil” helps
I like the peck idea. I peck deep drill all the time and for some reason I have not tried peck tapping in sprutcam. Guessing my mill has no rigid tap and for some reason I didn’t think of that option on 8l with rigid tap.
If the motors bogging down but it’s not chip welded to the work it’s going to come down to your motor is not powerful enough.
I input what I could and this feed app I use suggests much higher rpm.
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I always make the hole slightly larger than it calls for. That helps a lot. Tapping is way better. Imo threads are visibly the same and I have never had a thread strength problem.