Theading away from the head stock.

[M-Tecs]

On older lathes with glide bearings you can minimize spindle chatter by running the tool upside down. This prevent the cutting force from lifting the spindle (especially useful when parting off)

Modern CNC lathes create the same effect by moving the tool to the backside of the part. This makes good sense as the tool turret is rock-solid compared to the rotating chuck.

Glide bearing? Are you referring to Babbit bearings?

[uscra112]

I think he just means any sort of plain bearings (vs. rolling). South Bends were bronze. Not good for the high spindle speeds demanded nowadays, but at low speeds they are just fine. The front bearing on my SB 10" Heavy is loose, but due to the light cuts I do the lathe still works very well.

[Cap'n Morgan]

I think he just means any sort of plain bearings (vs. rolling). South Bends were bronze. Not good for the high spindle speeds demanded nowadays, but at low speeds they are just fine.

Exactly! Glide bearings or "glidelejer" is the Danish name for plain bearings. My brother still has dad's old lathe with bronze bearings and a full Norton gearbox (both metric and imperial threads without changing gear wheels) Before use, it gets a few squirts of oil in the main bearings.

[M-Tecs]

With the heavier industrially type machines chatter from the carriage lifting is not an issue. On machines that have some leadscrew wear accuracy is enhanced threading away from the spindle since there is less wear on that side of the leadscrew.

[john.k]

There are various lathe attachments that can do high speed threading......commonest Ive seen is the Ainjest Quick Thread ,commonly fitted to Colchester lathes ........however the ultimate in high speed single point is the Cri-Dan lathe......French ,but also made in England ,Italy ,and the US..........ive found at high revs (2000+) its almost impossible to get a thread that isnt bright and shiny.....mine is a Herbert Cri Dan Type B,made in England,also has a hydraulic copy attachment added on,and air chuck and air tailstock......paid $200 for it..scrap price.....weighs 2 tons.

[country gent]

The tool also goes a long way to a good looking thread.Just sharpening to the center gage on a coarse pedestal grinder wheel will get a proper thread form and thread but the rough cutting edge shows. frag a finger nail down it and feel the rough edge. I have a 60 grit for roughing and 120 for finish. but for the best from here I go to the surface grinder with a fixture. this fixture gives the correct 8* angles and true 60* form. It also leaves a very true sharp edge. When you grind or sharpen a tool a few passes with a fine stone to remove the grind marks will really clean up the thread

[Ernest]

just a note. I made sure the 4 jaw was on nice and tight and made very small cuts going away from the head stock on a rifle barrel and I cut the best threads I have accomplished so far. It was so much less anxiety provoking. I wouldn't think about doing heavy cuts that way but so far so good.

[alfadan]

Saw this interesting device: https://www.youtube.com/watch?v=Ic2k5Dyx_zY

[Hannibal]

The tool also goes a long way to a good looking thread.Just sharpening to the center gage on a coarse pedestal grinder wheel will get a proper thread form and thread but the rough cutting edge shows. frag a finger nail down it and feel the rough edge. I have a 60 grit for roughing and 120 for finish. but for the best from here I go to the surface grinder with a fixture. this fixture gives the correct 8* angles and true 60* form. It also leaves a very true sharp edge. When you grind or sharpen a tool a few passes with a fine stone to remove the grind marks will really clean up the thread

I find diamond hones to be very useful for such applications. They're nice and flat and do an amazing job if you'll take a few minutes.

[country gent]

It takes more force to loosen with a smooth even cut than a a cut thats interrupted or has vibration. Using the tail stock and a long nosed live center will also "block" the part/chuck in place helping keep it from loosening coming off

[Ernest]

It takes more force to loosen with a smooth even cut than a a cut thats interrupted or has vibration. Using the tail stock and a long nosed live center will also "block" the part/chuck in place helping keep it from loosening coming off

that is a great Idea!