Pilot hole for tapered pipe thread tapping-2

【英】困ったときの知恵袋詳細

Cutting Taps Pipe Threads How to use

When processing a Rc (PT) internal taper thread with a taper pipe tap, I heard it would be easier to tap the taper of the pilot hole with the tap. Why is it easier? Also, is there a problem when tapering the pilot hole with the tap? Currently, I'm tapping into a straight hole with a PT 1-11, but I think that would like to try using a taper hole if processing is made easier.

When processing a PT internal tapered thread with a taper pipe tap, a straight pilot hole is usually processed but if the pilot hole has a specified tapered shape, the volume of chips discharged will be reduced when cutting. I think some problems caused by chips can be solved this way. In addition, the total processing load amount on the tap is reduced when tapping into a tapered pilot hole, which leads to improvement in the tool life of the tap. If the pilot hole is tapered, the cutting chamfer section of the tap will not contact the pilot hole so, it will not be possible to tap unless it is done on a synchronized feed machine.
For details, please refer to the explanation on the attached PDF file for details.

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