Stupid things we do in the shop should be a sticky thread!!
Back around the turn of the century I was still in my arrogant infancy of CNC machining. I was used to brute force manual beast to make life easy so I was always trying to get creative, Ya know the old adage "give a lazy man a hard job and he'll show ya the easiest way to do it"? Well, That was my mentality in my early 30's.
I had started out on Sony and Acramatic controls so Fanuc was a whole new world for me, A bit intimidating and clumsy but I can handle anything! Welp, We get this big ass You-Ji VTL 100 horse main with 50 horse live spindle two speed gearbox,,,,,Oh yeah!!!! Pffft,,, Nope, POS couldn't pull a greasy string out of a cats Ass.
I've got this repeat job that's a plate of ductile iron 2" thick and about 8' in diameter that gets the usual turn, face, bore, and a bolt hole pattern with a few 4" pipe threads on the outer edge. This new Machines supposed to do all this in 2 ops by thread milling the outer pipe holes. I guess someone forgot to tell the dealer a 10,000+ pound chuck don't interpolate very well.
So now I'm looking up at this 20 foot tall beast of a machine and wondering how I can be more impressed with a powermatic drill press. All of a sudden this awesome, great, Beautiful idea pops in my head, So awesome I had to wonder why someone else hadn't thought about it. Let's get a 4:1 torque multiplier out and rigid tap that MF! I run over to the warehouse and grab the multiplier and 4" pipe tap, Then proceed to make an adapter from the 1-1/2 female side of the torque multiplier to BT-50. Even got all fancy with it, Ball detent so the multiplier wouldn't fall off the drive, You know, Safety first! Even made a socket to fit the tap with set screws to keep the tap in.
So now I've got this contraption in the spindle, recalculated the feed for 4:1 in my G84 line a 12' piece of 1-1/2 aluminium tubing to hold the torque side of the multiplier along with a very green operator to hit feed hold and feed override incase my invention got out of control. Here's the exact point my limited knowledge of Fanuc shined. I'm on the end of this cheater pipe and tell the kid "Hit it". I'm watching as the tap starts slowly into the hole and ever so slightly begins to cut as I start feeling the cheater begin to put pressure on my chest as I try and push back. It wasn't long before I realized that programming the spindle speed to the manufacturer's peak torque curve may have been one of my many bad decisions in this adventure.
Before maybe the second thread made its way around the bar began pushing me back while slipping on the unswept chips covering the floor. I turned my head to see just how far away from being pinned between the bar and the Haas Vf-5 when I realized I was already there. I began yelling "Feed Hold" at the operator as I'm starting to feel the true power of that spindle I had been laughing at earlier. I see the guy poking vigorously at the feed hold button and I'm thinking to myself "What the hell is wrong with this POS Now, why didn't it stop?" I don't think before this I had ever used E-stop since Acramatic controls you could just turn the Pot down to 0 and everything stopped, Even in a tap cycle. E-stop for some reason didn't even register to me while in the midst of being crushed. What did register was the feed rate knob, I grunt out with all but my last breath "turn the feed down"! As I here the clicking of the knob I'm thinking "Ok, Thats got it". Nope,,,That machines still getting even with me for making fun of it.
As I realise im not going anywhere and am at a point I can only hope for the best I notice the distance to go getting closer and closer to 0. Then I remembered "This Fkr has to go the other way now". I struggle to get out the words "Move!!!!! " Only to see the kid jump behind the hanging pendant controller. I reached around to try and get a grip on the bar so when it began pulling to reverse the tap I may be able to give it a quick yank to snap the tap loose from the threads. Nope, This rides not over yet! Since this thing was geared down 4 times it took about 8-10 seconds for the bar to drag me around a 12' radius all while kicking and fighting to snap the tap loose only to see this kids eyes looking like mister Magoo as the bar goes under the control. Now here he his pinned up against a Blanchard grinder that has no intention of moving, waiting for the resistance to let off the tap. Luckily it was taper pipe so it released much quicker than it engaged.
Soon after that the safety officer at Continental wrote us up for removing machine guarding and overriding the safety interlocks. I never saw the kid again, I guess he decided working around me wasn't a good life choice.
Ever since then I have always wondered why Fanuc doesn't have feed hold and feed override on G84?!?