Bugger. Well that may have been a fantastic waste of time, for my machine at least. When I run the Centroid post processor, I'm getting the correct feedrate into the hole but the retract feedrate is defined within the G81 canned drilling cycle - and worse than that, when I dig into the manual, it's a rapid retract (G0). The Fusion dialogues allow you to set the retract feedrate but the Centroid post processor ignores that and lets the canned cycle handle things.

Presumably, short of rewriting vast chunks of the post processor, I'm stuffed. I could use the boring cycle instead, which retracts at the feedrate but that's not a whole lot better unless you have one of the special (ie rare) tapping heads with the same reverse speed as forward speed.

There's a certain amount of tension movement allowed on the Tapmatic style heads but It's not clear what I could sensibly use there.

The jury is out. Not sure if this has been a waste of time or not until I explore my options....