Any safe way to thread away from my chuck on a South Bend 10K?

[twooldvolvos]

I'm slowly adding to my lathe skills and its time to make a thread. So of course I have been doing a lot of reading and viewing videos on line. I have a burning question. Is there any safe way to cut threads away from the chuck on a South Bend 10K? My understanding is that answer is no because I would run the risk of unscrewing the chuck (my chuck is a screw on type). If this is correct, I will need to learn thread cutting in the direction of my chuck. I have been too close for comfort to my spinning chuck with my tool post already and it makes nervous to do so. Any wisdom is appreciated. Thanks.

 

[SLK001]

Do you have a way to mount your tool behind your work? If you were to try (and wanted normal, RH threads), your machine would have to be run in reverse, your tool would have to be upside down and on the back side of your work.

In short, learn FIRST to thread normally. When threading, the back gears are usually used, so the speed is quite low. It is really an easy operation to master. If you have collets for your machine, their use would make threading away from the chuck safe. Although there are many who say, "I have a threaded chuck and I thread from the chuck all the time...", it is NOT a safe practice. It's kind of like saying, "I grind my tool bits without safety glasses all the time and I can still see with both eyes..." - a methodology that most would NOT consider safe. And even if the chuck doesn't come flying off the machine, you still have ruined your work if the chuck comes loose.

As for coming too close to your spinning chuck, are you using your back gears? Are you using a 29.5º angle on your compound (and feeding the compound)?

 

[jcp]

I have used my collet setup when it's 1/2" or smaller thread. I've also used the 3 jaw chuck, but have since quit. I learned to thread toward the chuck (a long time ago) and it's really no big deal. Start at a low rpm and work your way up. Practice is all it takes.

 

[DavidR8]

Indeed, threading toward the chuck is not a big deal.
I’m a novice and I’ve done it without any problems.

 

[bill stupak]

2x on the backgear, use the lowest speed you have along with backgear and practice with a thread pitch around 20 and you'll do fine.

 

[mickri]

I made a chuck keeper (wrong term?) that will hold a chuck in place if I have to run the lathe in reverse. It is a long rod that fits through the spindle. The chuck end is a close fit to the inside of the chuck and the outboard end is threaded. When it is snugged up I can not get the chuck to come off no matter how hard it try. Another forum member explained how this works. The two different threads, 8 tpi on the chuck verses 13 tpi on the keeper, work against each other preventing either from unthreading.

 

[twooldvolvos]

Do you have a way to mount your tool behind your work? If you were to try (and wanted normal, RH threads), your machine would have to be run in reverse, your tool would have to be upside down and on the back side of your work.

In short, learn FIRST to thread normally. When threading, the back gears are usually used, so the speed is quite low. It is really an easy operation to master. If you have collets for your machine, their use would make threading away from the chuck safe. Although there are many who say, "I have a threaded chuck and I thread from the chuck all the time...", it is NOT a safe practice. It's kind of like saying, "I grind my tool bits without safety glasses all the time and I can still see with both eyes..." - a methodology that most would NOT consider safe. And even if the chuck doesn't come flying off the machine, you still have ruined your work if the chuck comes loose.

As for coming too close to your spinning chuck, are you using your back gears? Are you using a 29.5º angle on your compound (and feeding the compound)?

Thanks for your advice.

I don't have an obvious easy way to put my tool behind the work so I will save that idea for another day.

This is how new I am. I have run the lathe in back gears just to see if I could make the chuck spin and that's as far as I went. I hadn't thought to thread in back gears but that is an excellent idea.

As for collets, I do have collets but haven't tried them yet. I take it that with collets, the draw bar will hold the chuck onto the lathe. Another good point.

 

[mickri]

You don't use a chuck with collets. The collets are held in the spindle by the draw bar and you need to have a thread protector on the spindle threads to prevent damage to the spindle threads.

As others have said there is no need to thread away from the headstock. When I started I used pvc pipe to practice on. Didn't take long to get the process down. Maybe an hour at most.

IMHO Mr Pete, aka Tubalcain, is the best source on the web for a beginning hobby machinist. He is a retired high school shop teacher. You could start with his beginning videos doing and making what he says and by the time you get through the first couple of hundred of his videos you will be well on your way. There are lots of other good videos by very knowledgeable people. But they are random helpful tips on how to do things. Mr. Pete starts from square one and leads you down the path. He is still my go to source to brush up on things whenever I run into a problem.

 

[Tozguy]

I will need to learn thread cutting in the direction of my chuck. I have been too close for comfort to my spinning chuck with my tool post already and it makes nervous to do so.

As already mentioned use the slowest speed possible. Do not run the chuck in reverse.
Start with an easy pitch like 16 tpi, or finer, do not thread to a shoulder, use a long enough piece so that the tool holder never gets close to the chuck. Make the situation as easy as possible.
You can even turn the spindle by hand (with power off) at first to build your confidence with the operations.
Its like learning to ride a bike or to swim. You will soon get more comfortable with the operation.

 

[SLK001]

As for collets, I do have collets but haven't tried them yet. I take it that with collets, the draw bar will hold the chuck onto the lathe. Another good point.

No, the wording of my answer was unfortunate - "If you have collets for your machine, their use would make threading away from the chuck safe". What I should have said is, "If you have collets for your machine, their use would make threading away from the headstock safe". You remove the chuck to use your collets. If you have the correct size collet, it is the best thing to hold your work with, both toward the headstock and toward the tailstock.

When practicing threading, be sure to support the work from BOTH ends. Flexing of the work can frustrate a novice to the point of abandoning the hobby. I don't recommend learning on PVC pipe, since it usually isn't round and it also isn't concentric on the ID and OD, unless you prep the pipe properly (which is also good practice). It's best to have a nut handy in order to test fit your threads, so practice with the thread pitch of the nut.

Having a SHARP tool of the correct geometry is also mandatory. Grind a piece of HSS to the correct geometry, then hone the edge to a very fine finish. DO NOT USE CARBIDE at first. LEARN to grind your own HSS tool bits. It is a skill that you will use as long as you have your lathe.