Problem- how to internal figure 8groove with fanuc 18

[k1m0e]

hi, i have over 10 years experience programming and running cnc lathes and mills, my problem is that every time a new person comes into the shop they say oh yeah i seen that done before, the problem i am having and have not been able to solve is turning a greese groove inside a bore with my cnc fanuc lathe, i want a spiral groove starting a zero degrees and spiraling once 360 degrees over a 3 inch span for example, then reversing directions and ending at 180 degrees, because the fanuc 18 maxes out at 180 inches per minute, its virtually impossible to do, is there a can cycle that allows this procedure, i tried using a threading cycle without any success as threading only allows 2 tpi, if i could use .25 tpi it would be great but as well impossible.. i think the only way this could be done as i have done it using a ballnose endmill on the cnc mill but takes forever and not with pretty results. any comments greatly appreciated.

[g-codeguy]

I don't know of any such canned cycle. I've been programming lathes for 24 years with the vast majority of them having Fanuc controls. Is it the control or the lathe that maxes out at 180 ipm? I've always used 120 ipm as the max for threading based on my early days with the Hardinge CHNCs that used Allen Bradley controls. That is what was in their manual. However I did thread a job one time at about 75% over that figure on a Hardinge Conquest 42 outfitted with an 18T control. It was how I finally eliminated chatter, believe it or not. That works out to 210 ipm.

Not at work, but I could check another job we do on Monday. It is an OD helix made with a modified groove insert. Not sure about the feed as it has been a while since we last run the job, but I do know that the machine hauls a$$ even at low rpm. It is machined with G32 threading. It has run on Hardinge Conquest 42s with 18T and OT controls.

[g-codeguy]

I think it is your machine, not the control that is limiting you. Just checked the helix program. I am running a G32 cycle at S230 F.31

EDIT: Oops! Guess that is below my 120 max ipm...provided I did the math right. Sorry.