Using the Cross Slide for Threading

If you try to cut threads using the cross slide considerably coarser than 20 TPI, you will run into more problems. When cutting 20 TPI on one of our hobby lathes it is pretty easy to get decent results using the cross slide only. Benmychree is correct, however. Doing it with the compound is the correct way to cut threads and will give excellent results with a tool ground correctly. My own soft rule is to cut threads using the compound for any pitch coarser than 20 TPI.
 
Old school just ramblin again. Although both methods work But for perfect threads: In my 50yrs threading i use the compound. My secret which is no secret' first you need a crosslide stop, thats one more thing not to worry about. In
my case one of my So.Bend long bed is the dedicated threading lathe. I use no wires no mic.(which I never use) I put the lathe in back gear and the belt on high speed. End of cut back out compound return to start wind in crosslide (to its stop)
feed compound .005 or so by the time thats done and my number comes up, hit the half nut & away we go.. About the
number or line on the dial. Forget it. On the setup after the TPI is set on the gear box = start it up and hit the half nut
now backlass is gone -- shut the power - now is reset the thread dial and MARK it with a sharpie. (got it) release 1/2 nut
return carriage to the begging then move cross slide to its thread stop turn lathe on move coumpoud until you touch off
on the part.....stop and zero the coumpound -- now dial a scrach pass turning counpound .004 or so when the sharpie
comes up hit the lever. thread age says OK. end of cut hit the lever !/2 nut: now if you did not cut a reliefe , end of cut,
don't worry at that point , end of thread you hit the half nut-- let it run right there then retract the cross slide.
When I see a peak at the top of the thread I stop and try a nut what ever then a no go a couple spring passes the usually
little better so feed compound 2 or 3 check it another spring pass. then try the nut is going on but a little stiff. Old
trick paint on valve grinding compond and I run the nut or female back and forth using a vise grip or something
use gloves and a wood on the bed. Bear with me ain't a writer but I give you sir 15 minutes using my method ..
Ok people new to this Please ya don't have to be policically correct or machine correct no wires no nothing. You
need look listen and feel. Rule one after all is said as you get deeper you gotta take litghter coumpond cuts cause the tool is getting deeper. sam got F's in writing in school 60 yrs ago
 
This is a screen shot from a canned threading cycle on a late 90's CNC lathe, eight parts that I ran this morning, 1 1/2"-12 internal thread 2 1/2" deep in 1018 steel.

You will notice the "Approach Angle" field is 29 1/2 Degrees as if threading from a compound. This is the default setting, I have found that this means little when making 1 or just a few parts per day, however it may help tool life when making 1000's of parts per day.

Many modern lathes have multiple options for approach angles when threading including alternating between the Z+ and Z- sides of the thread each pass.

A useful method of manually threading repetitive parts that I employ is to use the compound for controlling the diameter, advance it and leave it then retract the cross slide to clear when returning to the start. Return the CS to zero then advance the the compound for the next pass, this works very well on machines with an X axis DRO. One quickly grows weary of backing off the compound by the 50th part (-:


When threading on manual machines I use the cross slide only and have never had a problem in the last 30 years doing so. Having never used a hobby type machine I may be entirely wrong however.

Also very few manual lathes have a 3rd axis DRO for the compound, I dislike using hand dials.

 
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i have never cut threads with the crosslide.
i was taught to use the compound @29.5*.
i should try some crosslide threading to see the differences for myself.

i'm a little reticent before starting the process, that the method may not be ideal for 304 stainless steel, which galls terribly.
but i'll give it a go!
 
For one piece why not use a die to cut the thread.
The common sort of threading dies seldom start correctly and result in A "drunken thread", one that wobbles. An automatic die, like a Geometric die does not do this, but if one wants a concentric , non wobbly thread, single pointing is the way to get it.
 
i have never cut threads with the crosslide.
i was taught to use the compound @29.5*.
i should try some crosslide threading to see the differences for myself.

i'm a little reticent before starting the process, that the method may not be ideal for 304 stainless steel, which galls terribly.
but i'll give it a go!

Mike, if you thread with a HSS tool, try using a 15 degree side relief for stainless. It should cut fine.
 
i'm a little reticent before starting the process, that the method may not be ideal for 304 stainless steel, which galls terribly.
but i'll give it a go!
I was using 416 SS. Probably nothing like 304 though.
 
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