Author Topic: Cutting Threads on a Lathe.  (Read 620 times)

Online Bsharp

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Cutting Threads on a Lathe.
« on: May 29, 2021, 04:43:39 PM »


My brother showed me how to cut threads that are cutting away. [much safer and less stress of crashing]

Internal, you just need a left hand tap to revamp or a LH threading tool with inserts. No. 4



External, an upside down cutter holder. Run in reverse and feed out.

RH threads.

Just allow a little room for feeding in on the shoulder.

« Last Edit: May 30, 2021, 06:03:48 AM by Bsharp »
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Offline Bob Roller

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Re: Cutting Threads on a Lathe.
« Reply #1 on: May 31, 2021, 02:31:25 AM »
My way as well and no real need to run the lathe in back gear.
Bob Roller

Online Bsharp

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Re: Cutting Threads on a Lathe.
« Reply #2 on: May 31, 2021, 05:56:54 AM »
My way as well and no real need to run the lathe in back gear.
Bob Roller

Please explain how you get it to cut, if not running in reverse? [and feeding out with upside down holder]

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Offline James Rogers

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Re: Cutting Threads on a Lathe.
« Reply #3 on: May 31, 2021, 06:22:45 AM »
Back gear is the term for engaging the rear gears of a lathe that create a slower spindle with good power. Like low 4 or pulling gear : )

Online Bsharp

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Re: Cutting Threads on a Lathe.
« Reply #4 on: May 31, 2021, 03:25:09 PM »
Back gear is the term for engaging the rear gears of a lathe that create a slower spindle with good power. Like low 4 or pulling gear : )

Terminology for Hi and Low, not Forward and Reverse.......Thanks!

My ole 1937 Southbend does well in High, Low speed. I may look at Low, High speed....one less thing to change.

Thanks for the tip, Low in High is very doable on the ole girl, just a little more noise. Not too fast!

But anyway, you need to get the tooling to feed away from the chuck when threading.

Not only safer, but it can be faster.
« Last Edit: May 31, 2021, 04:01:32 PM by Bsharp »
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Offline yellowhousejake

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Re: Cutting Threads on a Lathe.
« Reply #5 on: June 01, 2021, 06:24:16 AM »
For those who have a screw on chuck like me, you need to flip the cutter upside down to run it from the back and cut the threads away from the chuck. Just reversing the headstock direction and cutting with the tool right side up can cause the chuck to loosen.

DAve

Offline James Rogers

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Re: Cutting Threads on a Lathe.
« Reply #6 on: June 01, 2021, 02:04:10 PM »
For those who have a screw on chuck like me, you need to flip the cutter upside down to run it from the back and cut the threads away from the chuck. Just reversing the headstock direction and cutting with the tool right side up can cause the chuck to loosen.

DAve

Mine is a screw on also

Online Bsharp

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Re: Cutting Threads on a Lathe.
« Reply #7 on: June 01, 2021, 04:30:06 PM »
Mine is a screw on, never had it loosen.

It doesn't have a brake, just coasts to a stop. That could make a difference.

You are just making light cuts.

Any way works well for me and  my brother and his 1954 Southbend. Screw on chuck.

If you are using a 5C collet, they will not un-screw.
« Last Edit: June 01, 2021, 08:04:43 PM by Bsharp »
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Offline P.W.Berkuta

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Re: Cutting Threads on a Lathe.
« Reply #8 on: June 17, 2021, 06:39:01 PM »
Look on YouTube for Joe Pieczynski's videos - this guy is SHARP and full of good information. He shows you how to thread with the tool upside down and reversing the rotation of the work which will make the carriage travel towards the tailstock. I have a 12" X 36" older Jet 2 HP lathe with a screw on chuck but I use collets (I have 1/16" to 1-1/8" sizes) 90% of the time so unscrewing of the chuck is a non-issue for me.
"The person who says it cannot be done should not interrupt the person who is doing it." - Chinese proverb