Hi all,
I'm using an PCNC1100 with their ER20 floating tap head and YG brand M3 threadforming tap.


I'm trying to form tap some M3x0.5 holes in AL6061 about 0.30" deep, hole depth is 0.40". The problem is, about the top half of the threads are being pulled out, so I can wiggle the screw into the hole past several threads before it stops and I have to start turning it.

I have had success using thread cutting taps of this size and others with not issues.

I checked on a manual mill, using the same 7/64" (0.109") drill and same M3 tap, power tapping with a Bridgeport quill. Threads are fine. Inspected the tap, threads are not damaged or galled up.

So it must be something with my program or a setting.

I've tried both my original program generated in Fusion360 and then I made a test program using Pathpilot covnersational, same results, most of the threads are pulled out of the hole.

Is this a dwell time issue?
Am I not setting the tool length correct? (I jog down to a piece of shim stock and zero minus the thickness of the shim when I feel friction, since the tap head is spring loaded, its not a hard stop like a drill bit would be).


Any help would be appreciated.