[modeleng] Re: Mystery Thread & New Loco

Barrie

I find the easiet way to screw-cut is to stop the lathe at the end of the
cut, withdraw the tool, and reverse the lathe - in this way whatever the
thread, it is always on track.

I bought an ancient Hardinge last year, and with this lathe, screwcutting at
speed is a doddle!    You can thread up to a shoulder, and the lathe will
stop.
The topslide has a device for withdrawing, and the reverse on the
screwcutting does not lose the track   Hardinge suggest that you do not
screwcut above 1000 rpm!

Cheers!   Hubert

----- Original Message -----
From: "Barrie Purslow" <bpduo@xxxxxxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Monday, August 14, 2006 11:57 AM
Subject: [modeleng] Re: Mystery Thread & New Loco


> Al,
>
> The thread had stripped about 1/2" into the end of the tube but the
original
> thread was about 3/4" long so I set up the thread cutting operation to
> extend the remaining thread using a tpi of 26. I suspect the thread is
> actually 1mm pitch as the new thread does go slightly tight when a collet
is
> screwed in more than 1/2". I avoided the metric pitch because, although my
> lathe will cut them, it is not possible to release the clasp nut from the
> leadscrew between passes! I felt sure this would result in a catastrophe!
>
> Regards,
>
>
> Barrie
>
> >


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