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Anybody used an "Electronic lead screw" on a manual lathe?

Certainly cheaper than transposing gears for metric. At that low price it must be a do it your self kit. You will probably building a lot of brackets and adapters. Babin sells one for the HLV-H, never used that one either but it will cost more and probably has all the hardware for the installation.
 
most cnc synchronize spindle turning to slide travel speed
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the problem happens when spindle motor stops but there is backlash in gearing and if chuck keeps turning even 1/2 rev and the slide was not moving. thats why extension compression tap holders are used. if tap still turning but tap not moving forward it wants to screw into part more. if a rigid tool holder it wants to pull tap out of tap holder
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not many cnc will stay synchronized even in deceleration. sure some will but they got special ball screws with anti backlash nuts and dont have backlash in spindle gearing. might have special anti backlash gearing
 
Hi

I looked at this quite a while ago. I don't think it's a bad system but I won't be fitting one to my lathe.

The fundamental flaw then (and probably now) is that the spindle rpm was only sampled once per revolution.
If that is still true, then it will take a few revolutions for the control loop to settle down. That will make the first few threads wonky.
In practice this means you should extend the part to make 5-10 extra threads that are then cut off.


Dazz
 
Anybody used an "Electronic lead screw" on a manual lathe? Says it can drive the Lead screw and crosslide on an old manual lathe to cut any type thread, precise tapers, etc.

For $400, too good to be true?

Electronic Lead Screw Main Page

Thoughts or feedback?

Thanks,
MG

Doing it "right" means integrating it with the lathe from the outset. If that was NOT done, figure $4,000 and UP. Potentially WAY "up". Not $400.

If I had the need, I'd scarf-up some of the "many, many" masters in the used/orphaned market made by and for Hardinge's "thread CHASER" system, then adapt the <whatever> manual lathe to make use of them. You won't need all possible pitches.

Get it right, it makes the ONE thread fitted for, that go. Accurately. Very. And is really hard to screw-up.

"All manual", too. Truant electrons can go devil some OTHER pilgrim's brain.

If you really WANT CNC? Buy it ready-made and already integrated and proven.
 
Popping this thread up as I've just watched the first set of the Clough42 videos - and he clearly has at least the basis for getting it right - high sample rate of the spindle, with the servo high sample rate of the leadscrew - closing in on how this function would be done on any cnc lathe without scales - except of course no ball screw. But somehow threading works on lathes without ball screws anyway....
 
I have never used one, but I kinda like the idea. I was doing a lot of hydraulic repairs for a bit and really, really wanted one of these to make metric threads easier on my inch manual lathes. I haven't cut a metric thread on a lathe in awhile so have not thought about this for awhile.

The hobby cheap part goes right out the window when you get into real size machines. If you're going to de-couple the gearing from the spindle to the feedworks you need several HP to drive that stuff. Even the lowest end of Chinese stuff is going to set you back $500+ for servo and driver. Then you get to buy/make/figure out the control/user interface. If you want to buy new, real automation parts to do this it will set you back a small fortune.

That website shows a TINY stepper motor. That little thing isn't going to do fuckall unless you have a 7" harbor freight POS.
 
Popping this thread up as I've just watched the first set of the Clough42 videos - and he clearly has at least the basis for getting it right - high sample rate of the spindle, with the servo high sample rate of the leadscrew - closing in on how this function would be done on any cnc lathe without scales - except of course no ball screw. But somehow threading works on lathes without ball screws anyway....

I'm no expert in this but decent servo drives ( Omron ) have built in the gearing he's busy implementing. Also, it's worth looking around for something called K-flop. Here : Dynomotion Motion Control Boards for CNC Manufacturing and Robotics Applications

The designer/owner seems to really know his business. No point re-inventing the wheel.
 
I also remember looking at it back then. And I also did not like the one pulse per revolution of the spindle. Not only might the first few threads be funny, but if you hit a harder spot in the material being threaded, then the thread you are cutting and perhaps one or several more past that point will also be funny. Not my idea of a quality system. But they, of course, discounted any such concerns.

IMHO, there should be at least 100 pulses per revolution to get anywhere near what you would want. Even more for high TPI threads.



Hi

I looked at this quite a while ago. I don't think it's a bad system but I won't be fitting one to my lathe.

The fundamental flaw then (and probably now) is that the spindle rpm was only sampled once per revolution.
If that is still true, then it will take a few revolutions for the control loop to settle down. That will make the first few threads wonky.
In practice this means you should extend the part to make 5-10 extra threads that are then cut off.


Dazz
 
I also did not like the one pulse per revolution of the spindle. Not only might the first few threads be funny, but if you hit a harder spot in the material being threaded, then the thread you are cutting and perhaps one or several more past that point will also be funny. Not my idea of a quality system. But they, of course, discounted any such concerns.
That's how almost all commercial lathes work ... There's a trigger pulse, then the control coordinates the speed and feedrates. That's the reason you can't change speeds between passes. (Newer lathes maybe have better compensation for the servo lag, but that's how most anything older than 2000 was.)

There were a few more advanced controls that could do stuff like the weird cable drum thread that's not constant, but that was an unusual and extra-expense option.
 
I'm in agreement with wanting a much higher pulse count for the spindle. What if you want multi-start threads? A single pulse would be useless.
No, you start the thread one, two, three pitches farther away in Z. That's how every one I have ever used works.

It would cost too much to treat the spindle as another axis. ($100,000 lathe and they're worried about $12, but that's life in the fast lane.)

On newer stuff where the spindle is an axis, that's different. But straight ol' 2 axis lathes, it's just speed, feed and a trigger pulse. Works fine.

You can ask Vanc to confirm on newer stuff, but on older ... that's how it is.


As I remember, Hardinge had a weird way to do threads, that might be interesting for manual lathes. It was more of a copy thing. Never owned one though, you'd have to ask a Hardinge guy.
 
Ah, but I happen to need to make threads that are just as long as the travel of my lathe - so nogo on shifting over a few more mm.

Gotcha, smart guy!! :toetap:
Can't do it. Maybe on a tiny lathe but anything with decent size turret and cross-slide, you have to allow some up-to-speed distance. Inertia, you probly heard about that.

I can't speak for Jap manuals but all the US control manuals explained this. They even had a formula for the lead-in distance required, based on pitch and speed.

It would be pretty unusual that you couldn't get the threading tool three pitches father away from the end of the part :)
 








 
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