Anyone Have Trouble With Threading On 1340 Lathe

[Bob Korves]

Or use the method posted in post #12 here: http://www.hobby-machinist.com/threads/cutting-metric-threads.22504/#post-199388

It is actually pretty easy to cut metric on an imperial machine (or vice versa) and disengage the half nuts long enough to pull out from the work and stop the motor. Just put the half nuts back in when the number you had before comes around after you start the lathe again in reverse. It is a MUCH safer method than others. Another good approach is to cut on the back side of the work while cutting toward the tailstock. With both techniques combined, it is child's play...

 

[Downunder Bob]

It is actually pretty easy to cut metric on an imperial machine (or vice versa) and disengage the half nuts long enough to pull out from the work and stop the motor. Just put the half nuts back in when the number you had before comes around after you start the lathe again in reverse. It is a MUCH safer method than others. Another good approach is to cut on the back side of the work while cutting toward the tailstock. With both techniques combined, it is child's play...

Yes that should work, But I think I'd want further proof before trying it on a critical job.

Like all child's play, it's bound to end up in a mess.

 

[Bob Korves]

Yes that should work, But I think I'd want further proof before trying it on a critical job.

Like all child's play, it's bound to end up in a mess.

Practice it on a piece of scrap until you become confident in the method. That is what I did... Don't take my word for it, prove it to yourself.

 

[bench]

Hi, Nice, you are the first person since I joined who has owned up to having a LD lathe, and the fact that yours is a LD1216 GH the same s mine is quite something. How do you like the 3ph motor and VFD. As I said I opted for the single ph and no VFD. Quite happy with my choice. I could have gone with 3 Ph, as I have 3 ph connected here, but just didn't think I would need it. how long have you had your lathe for and have you done much work with it yet?

Bob.

Hi,I owned the machine since last October and so far quite happy with it. I have no experience with a single phase motor so cannot say whether 3ph is better than 1ph, but running the machine on a VFD is quite convenient for its speed adjustability. I modified a few things. Crashed once the carriage at the tailstock end, and since then power feeding makes noise when the lathe is running at high rpm. Rather than fixing the QC gear box I added a DC motor to run the power feed shaft. It is very quiet and the feed speed can be adjusted continuously, in the middle of machining---a very convenient feature. Also added an extra rotary switch for the spindle, which ended up as my main switch for the spindle. To get a decent surface finish for a steel it seems I have to run the lathe at high rpm, above 1500, for a half inch stock using a carbide insert. I am not quite comfortable with the rpm. What is your typical high rpm?

 

[darkzero]

Yes that should work, But I think I'd want further proof before trying it on a critical job.

Like all child's play, it's bound to end up in a mess.

I've been using that method ever since I found out about it & never had an issue. It's the only way I do it for metric threads on my imperial lathe.

 

[Downunder Bob]

Hi,I owned the machine since last October and so far quite happy with it. I have no experience with a single phase motor so cannot say whether 3ph is better than 1ph, but running the machine on a VFD is quite convenient for its speed adjustability. I modified a few things. Crashed once the carriage at the tailstock end, and since then power feeding makes noise when the lathe is running at high rpm. Rather than fixing the QC gear box I added a DC motor to run the power feed shaft. It is very quiet and the feed speed can be adjusted continuously, in the middle of machining---a very convenient feature. Also added an extra rotary switch for the spindle, which ended up as my main switch for the spindle. To get a decent surface finish for a steel it seems I have to run the lathe at high rpm, above 1500, for a half inch stock using a carbide insert. I am not quite comfortable with the rpm. What is your typical high rpm?

Mine is only a couple of months older than your's. Your not likely to notice much difference between single ph and 3 ph except you will have a little higher starting torque, and some say that 3 ph is smoother, I doubt if you would notice that. The real difference will be with the VFD. The ability to adjust the speed is useful, but I don't think it's worth the cost. I just use the gearbox, isn't that what its for. My top speed is 1500 rpm, and I've rarely used it. I mostly run around 600 to 900. Sure I would like a lower speed for difficult screwcutting. Continuously variable speed would be useful for facing large diameters, but other than that ?. Ok your dc drive is useful, but I suggest you fix the damage you might need it for screwcutting.. I haven't crashed a lathe since I was an apprentice about 55 years ago, but I guess there's always the next time.

Bob