Author Topic: 20 tpi x 9.5 degree taper ?  (Read 424 times)

Offline V 45

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20 tpi x 9.5 degree taper ?
« on: May 07, 2019, 02:24:30 PM »
How to identify and cut this thread pitch?  Wasn't sure where to put this. I need to make a couple of these plugs. But haven't a clue how to.
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Offline cnr6400

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Re: 20 tpi x 9.5 degree taper ?
« Reply #1 on: May 07, 2019, 03:22:54 PM »
To do tapered threaded plugs a technique I have used is to mount an adjustable offset centre in the lathe tailstock to set the stock at the needed angle. The threads can then be cut as usual on the lathe. If you don't have an adjustable offset centre, you can offset the tailstock on many lathes, but getting it reset to centre afterwards can be tricky. A boring head as used on milling machines can be used as an adjustable centre too, if it has a Morse taper shank that fits the lathe tailstock.

Offline V 45

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Re: 20 tpi x 9.5 degree taper ?
« Reply #2 on: May 07, 2019, 03:36:12 PM »
That's informative....Thank you !
Never assume the implied task has been completed !!

Offline jadge

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Re: 20 tpi x 9.5 degree taper ?
« Reply #3 on: May 07, 2019, 03:39:57 PM »
It depends upon whether the thread form is perpendicular to the axis of the work or is perpendicular to the taper. If the latter then the offset works, if the former you'll need a taper attachment or hydraulic copying unit.

Andrew