On Sunday 04 September 2016 06:47:02 andy pugh wrote: > On 4 September 2016 at 11:05, Gene Heskett <ghesk...@shentel.net> wrote: > > I have wondered about those usages, and it occurs to me that these > > usages of an alpha character should have their "scope" restricted to > > the life of the canned cycle being executed, to disappear with the > > stack cleanup as that particular canned cycle was exiting. The fact > > that its even being discussed tells me it is non-volatile. > > No, the multi-spindle G76 needs a letter to tell it which spindle to > synchronise to.
Thats no doubt true, but I've just found that the tapered thread I need CAN be done with the G76 we have. Its not even an error if E is as long as the drive line - tp_mm. If that value is exceeded, that should be an error but in 100% of the cases where the drive line starts off the end of the workpiece, it is of zero consequence because what it does is move to the I position, and next extends the overshoot distance to the right, cutting air, then it runs a taper the full length of the thread, air included. Angle of the taper is UNK, but for my purposes, may even be slightly more than what I was playing with before. Attached is a screenshot of an external thread, doing a 50tpi cut, 17mm's long. And a 2nd screenshot of cutting a virtual nut. The I -value will be reduced for the nut else the tool backs into the threads on the other side. So, once the little monster can make swarf again, I am off to the races as I can make the needed nut for the shaft that is already threaded. And I can do it with the code we already have RIGHT NOW! ANAICT, the angle can be reduced by leaving the Z end point alone, but makeing the start point cut more air. In this case I defined the E length as drive line length - tp in mm's. And will assume z is touched off about a mm to the right of the end of the workpiece. Conversely, a greater angle is obtained by moveing z_end to the right. If a shorter tapered section can be tolerated, higher tapers would of course have a taper start point that moved to the left as E was reduced. The grid in those snapshots is a 1mm grid. Can anyone determine the actual angle achieved? For me it looks about right, but thats best described as a SWAG. :) Thank you once again for making me test a what if. :) So please do not take away the E of G76. Any chance you could put a - sign in front of an S number to select the spindle, so -s6 s1000 m3 would spin spindle 6 at 1000 revs? Ditto for a new G76, use a -e6 to cause it to track spindle 6? Treat G33 similarly? Existing code would not be broken, it just wouldn't be able to use the new features until the gcode fed it was updated. Looks like I have some downtime, the BoB running the little monster has blown a SN74ACT245N. Buggar is drawing an extra amp, enough to partially shut down an lm317 which was slowly warming the 1/4" alu end plate of the driver box and this chip is burn your fingers hot in 30 seconds with no i/o connected. I'd say that makes it the usual culprit. Digikey, 10 of them since there's 3 in this BoB, P1 mail, still under a $20 bill. So, I guess I catch up on the weed eating etc around the homestead. Till at least Thursday. Not that it needs it of course. :) Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
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