Logan Model 200 Servo Threading

Yep, this is the "Hobby" Machinist site, after all. I'm doing this mostly for my own entertainment, with the reward being my own satisfaction, some validation from like-minded folks, and a lathe that is really nice to use. If money changes hands I incur liability and expectations of support.

The anesthesiologist was dealing with a lawsuit while I was working for him. A hospital technician had replaced the air fitting on a ventilator with an oxygen fitting, resulting in a rather intense fire in the operating room, and they went after the staff in the OR, the hospital administration, the manufacturer, and the designer. Everyone, in fact, except the technician responsible. Observing what he had to go through made me paranoid.
 
Totally awesome! How does it work for regular feed for cutting?
Robert
 
Can you give us some follow up on this awesome project!?
Robert
 
rwm said:
Can you give us some follow up on this awesome project!?
Robert
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Had some family health issues to deal with, but I’ll be getting back on it soon. Last thing I did was switch to a “spare” controller from a different source to see how it worked. I expected it to be compatible, but it wasn’t working very well. Lots of noise and resonance, so I’ll have to hook up to the RS232 port and tune it, I guess. I’m hoping a download from Leadshine will provide the utility and guidance, but the documentation is a little sparse on these things. I’ve verified most of the feed rates against a dial indicator and the DRO and everything has checked out so far.
 
Are you using a thread dial for threading?

Or are you able to run the motor in reverse and have the stepper turn the opposite direction?

I'm sure you could have the arduino keep track of the steps and return to a "zero" point without having to run the motor in reverse especially if you add limits.
 
jh1990 said:
Are you using a thread dial for threading?

Or are you able to run the motor in reverse and have the stepper turn the opposite direction?

I'm sure you could have the arduino keep track of the steps and return to a "zero" point without having to run the motor in reverse especially if you add limits.
Click to expand...

I've set it up so everything works pretty much "normally," thread dial included. The microcontroller just takes the place of the change gears, and adds the ability to do metric, diametral and module pitches. It does allow switching the lead screw direction on the fly, which is useful for facing.

I've been planning all along to add the ability to set limits, but I've started having second thoughts. It works so well as it is, and I'm not sure the added complexity would really be worthwhile. I plan to give it a try and see how it feels, though.
 
I've been neglecting this thread (and project). I thought that I ought to put up a couple of pictures of what I've got at this point. The electronics are enclosed. I extended the drum switch bracket and mounted the touch screen on a friction hinge. The main box will mount on the leg under the headstock:

IMG_1963.JPG

The "home" page. The touch screen and knob make for a very straightforward interface:

IMG_1970.JPG

There is a setup page for displaying the valid spindle RPM's for a given feed rate and adjusting the screen brightness, and a page for setting feed limits, but I don't have pictures. Right now I'm re-writing the jog code, but I'll have it all working any day now. I swear.
 
What a mod! It is, in my mind at least, still very cool. On an Ol' Logan Model 200 no less. :encourage:

Now all that is needed is a complete write up with diagrams, schematics, drawings, and a BOM. :grin: (I'll see myself to the door now...)

Wish I had the talent, not to mention the time, to take this on and do mine up.
 
I could stop right where I am and just have a programmable gearbox, jog, and instant feed reverse, but I think it would be cool to add a couple of "enhancements" while I'm at it. I was watching Robin Renzetti make a differential screw (look him up on YouTube and Instagram if you haven't already) and thinking how neat this would be for that. Want 0.001" per turn? Do one thread at 0.025" pitch and the other at 0.026" and there you are! Of course, that means that I have to add "custom" feed rates now in addition to the 79 fixed inch rates that I already have. It's only software, right?
 
Getting into "differential screws" now -eh? I caught that video of Robin's awhile back.
Soldering fumes are being ventilated properly aren't they? :grin:
Edgewood is only @6700' so lack of oxygen isn't a factor...

Talk about breathing new life into Old Iron.
 
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