Pitches and feeds chart on the Hercus 260 now has me baffled.

Last week I cut a M~14 x2 thread single point with no hassel. According to the chart #4 is engaged with B lever in position. Stud gear 18 was left on as I interpreted the chart that it can be either ~18 or 45.
See the chart.
Attachment 390189

Beautiful thread that mates perfectly with a corresponding M~14 x2 internal cut with an M~14x2 tap.

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Today I tried to cut a ~1.5 thread in a brass sleeve. I checked my settings made a scratch pass. To my surprise, the scratch didn't confirm ~1.5 but ~ 0.8!

So I changed the stud gear to the 45 and got a scratch pass done that confirmed ~1.5 on my gauge.

So I proceeded to cut the thread. Being a little fine on brass it was difficult to see but as I proceeded it seems the peaks were cut as the valleys were broadened. It seems that each pass cut in the same pattern but not in the same position. I hasten to add this happened on my first attempt to single point a thread as I had the compound set at 30° so my advancement of the compound cut off the thread in the same way as this shows on each pass. Since then I have learned to set the compound angle to 60°

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So my questions are 2.
1. Why did the first scratch pass not conform to ~1.5 until I changed the stud gear from 18 to 45.

2. What am I missing to result in my thread being eaten?

Thanks for any help.
Attached Images




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