# How to cut threads on lathe that does not have ability.



## toolholder (Aug 21, 2014)

I bought a 2006 Central Machinery 3 in 1 that doesn't have thread cutting ability. So, what tricks do I need to learn or what do I need to buy that will facilitate thread cutting? :thinking:


----------



## toolholder (Aug 21, 2014)

I just bought this 3 in 1 today and have little knowledge, learning fast. It seems there is not much love for the HF 5980, I paid $500 for it barely used with about $1k worth of tooling. I will be doing small aluminum parts with it. It seems like the only way to do threads is make up a  gear drive from the spindle to the lead screw, I'll see how much I like it before I get excited about that.


----------



## DMS (Aug 22, 2014)

You could also do something called an electronic leadscrew (ELS). It's sort of half CNC. Basically you put a motor and drive screw on the carriage, and an encoder on the spindle, and a small box controls the "gear" ratio. 

If you are not doing oddball threads, you could always just make a tailstock tap/die holder. They work pretty well, and are fast in most cases than single point threading.


----------



## Andre (Aug 22, 2014)

Use a tailstock die holder with a HSS round split (adjustable) die. Dont use a hex or non split die as they are meant to clean threads not cut them.


----------



## toolholder (Aug 22, 2014)

I need to do about 200 thread operations (all same) in the ends of roughly 1" aluminum tubing which can be thicker and cut down and/or made a collet for to keep from distorting. I was thinking of the ELS method or gearing down the chuck to around 60 rpm and sticking tap in it, make some sort of jig to hold tubing. 

The other operation is about 200 plugs that will screw in to the tubes. Maybe I could do basically the same thing as I do tapping. The concerns I have are having a clean bottom in the tube threading and clean end of die operation.


----------



## billdeme (Aug 25, 2014)

Do you have a drill press?  If you don't have access to a tapping head, I've chucked LIGHTLY on a tap and jogged it down to depth and reversed back out.


----------



## toolholder (Aug 27, 2014)

billdeme said:


> Do you have a drill press?  If you don't have access to a tapping head, I've chucked LIGHTLY on a tap and jogged it down to depth and reversed back out.


I do have a drill press. But I decided to use the lathe to tap with. I am cobbling together a speed reduction to get the spindle speed down to less than 60 RPM, on paper it says 48 RPM.


----------



## Rbeckett (Aug 27, 2014)

Can't remember exactly where I saw it but a fellow added a small stepper motor and a chain drive rediction unit to his lead screw and did threading and powered cross slice operation.  I Bought a set of gears and a belt as well as the stepper motor, but have been too lazy to build the appropriate electronics to power the stepper.  I sort of envisioned the capability of just doing powered long axis operation and a quick jog capability..  I got the gears from Canada at Motion tech  I think.  It has been a while since I ordered them.

Bob


----------



## TOOLMASTER (Aug 27, 2014)

made this last year.


----------



## chips&more (Aug 27, 2014)

If you are talking about having the spindle in sync/time with a lead screw for threading and not just threading with dies and taps. I would be looking for another lathe. Sorry, but I think by the time you dilly dally around spending gobs of time and money, you will probably find out I was right…Good Luck.


----------



## toolholder (Aug 27, 2014)

I am going to keep the lathe as it's a nice compact size to have on the benchtop. I think I am going to like having multiple machines so I'll get something small later that does good with threads. A year or two get a full size lathe and mill. This is part of my new career so whatever it takes to get the job done right.

I think slowing the lathe chuck down to less than 60 RPM and chucking the tap/die and loosely holding the work peice will do for now, hopefully.


----------



## janvanruth (Aug 29, 2014)

toolholder said:


> I am going to keep the lathe as it's a nice compact size to have on the benchtop. I think I am going to like having multiple machines so I'll get something small later that does good with threads. A year or two get a full size lathe and mill. This is part of my new career so whatever it takes to get the job done right.
> 
> I think slowing the lathe chuck down to less than 60 RPM and chucking the tap/die and loosely holding the work peice will do for now, hopefully.



You might consider to crank the spindle by hand.
i recently saw a thread, dont know where, somebody made a crank that went into the spindle,  where it wedged itself.
Seemed like a easy contraption to make and worked just fine.


----------



## billdeme (Aug 29, 2014)

You van do the same thing in your lathe, just not as fast. Chuck lightly with a chuck in your tailstock then jog forward till you bottom out then reverse. If your tap spins just chuck A LITTLE tighter till you find that sweet dpoy


----------

