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mars-red
11-02-2016, 08:25 PM
Whenever there are discussions about plain turning lathes, I tend to jump in to their defense... I just have an inexplicable fondness for them. I especially love the crazy attachments available for some of them.

My latest video features a threading attachment for one of the Hjorth lathes. One of my subscribers asked for details on this attachment so I took the opportunity to also discuss single point threading on a plain turning lathe in general, and some considerations to keep in mind when designing such an attachment.

https://youtu.be/3ies9MiCxEE


https://www.youtube.com/watch?v=3ies9MiCxEE

Alan Smith
11-03-2016, 04:44 AM
Very enjoyable video Max. Really like the look of the Hjorth lathe, is it North American or European in origin? What sort of collets does it take? Proprietary to the lathe I assume.

mars-red
11-03-2016, 08:37 AM
Very enjoyable video Max. Really like the look of the Hjorth lathe, is it North American or European in origin? What sort of collets does it take? Proprietary to the lathe I assume.
Thanks Alan! Hjorth had his workshop in Boston, apparently down the street from Rivett. Just as Hjorth used many designs from Rivett in his machines, he also used Rivett collets. The machine in the video takes 4NS collets, and some also took 5NS.

CCWKen
11-03-2016, 11:06 AM
I don't bother with setting up the gears on the A/C and single pointing short threads like that any more. Takes too long. I slap a die in a die holder chucked in the unlocked tail stock and let 'er rip. It takes about as long to change the lathe speed and switch to back gear as it does to cut the thread with the die. But I'm done in a few minutes with acceptable precision. Most of what I do is one-off or repairs with little time to "play". I use the same procedure for internal threads by chucking a tap. It's been years since I single pointed threads. :)

Mcgyver
11-03-2016, 11:33 AM
I don't bother with setting up the gears on the A/C and single pointing short threads like that any more. Takes too long. I slap a die in a die holder chucked in the unlocked tail stock and let 'er rip. It takes about as long to change the lathe speed and switch to back gear as it does to cut the thread with the die. But I'm done in a few minutes with acceptable precision. Most of what I do is one-off or repairs with little time to "play". I use the same procedure for internal threads by chucking a tap. It's been years since I single pointed threads. :)

Pretty much SOP, quick and it works very well......until it doesn't

mars-red
11-03-2016, 11:39 AM
Pretty much SOP, quick and it works very well......until it doesn't
Definitely, 9 times out of 10 I do the same. Since acquiring that array of Hjorth die holders that I can use on the Hjorths and the Rivett, die threading is even easier and quicker than it was.