Electronic Lead Screw

[NevNZ]

Hey guys, I'm interested in installing an electronic lead screw on my lathe (Opti-Turn TU3008).
I've read a lot about the Clough 42 system and watched all of James Cloughs videos which I found to be excellent. I see there's also a couple of commercially produced units now. I came across another one being made by Maxim Kachurovskiy in Germany, also seems to be produced in his workshop (photo below). Has anyone installed one of his ? I don't have any electronics experience to speak of, but I like the idea of the project. I'm interested to get a comparison, any feedback is welcomed.

 

[markba633csi]

Interesting control panel- looks Egyptian

 

[Firstram]

Interesting control panel- looks Egyptian

Efficient use of space for sure!

 

[WobblyHand]

Lots of systems out there for an ELS. Here's mine on the bench testing out integration of the DRO display. It has a printed case and sits on top of the headstock. I rolled my own set up, code and PCB with a touch panel. That way there are soft buttons which are context sensitive. When I get some quiet time I plan to implement some convenience functions like feeding to a stop and eventually threading to a stop. I've had my ELS running for a year now, and I think it's terrific. Makes things a lot easier, especially with the integrated DRO. I added the DRO stuff specifically to allow the system to do thread to a stop. Hopefully it won't be too hard to get it to work once I work out the details.

 

[Just for fun]

@WobblyHand That sounds like a really nice setup, way outside my pay grade. That's really neat that you can do that sort of stuff.

 

[RJSakowski]

I have had the Clough42 ELS working on my lathe for a couple of years now. I have a Grizzly G0602 lathe and it seemed that this would be the path least likely to have gotchas. I used a different hybrid stepper than Clough did. I mounted mine under the lathe bed as @WobblyHand did. I also made my own display interface. For the electronics enclosure, I used an old breaker box. I also separated the power switch for the control electronics and the stepper. This allows me to have the display on without activating the stepper. When I want to use power feed or to thread, I just power up the stepper and I'm ready to go.

I found the stepper torque to be lacking and took advantage of the integral gear box on the lathe to gear down 2:1 to increase torque. I had chosen a NEMA24 motor as it fit nicely under the lathe bed and made a compact installation. With the gear change, I had to change the parameters in the firmware accordingly. I could have accomplished the same thing by using different gearbelt gears on the stepper.

The one thing that I found to be lacking was the inability to easily add custom thread pitches. I did add one by modifying the firmware but that isn't a convenient solution. The big problem is the Clough interface. The available buttons don't leave much of an opportunity to do this but an individual on Clough's github site has done a modification of the firmware to create custom metric pitches with the OEM interface. I haven't implemented this my self yet as I wanted custom Imperial pitches as well and it is a bit of a pain to flash new firmware for half of a solution. I think I would be able to modify the firmware to meet my needs but I would have to immerse myself in the code to get an understanding of what I was doing.

Aside from that shortcoming, the Clough ELS has been working flawlessly.

 

[WobblyHand]

@WobblyHand That sounds like a really nice setup, way outside my pay grade. That's really neat that you can do that sort of stuff.

It took me a while to do this. Over 6 months, so hardly an overnight success. Had to learn a lot along the way. Thanks for the compliment, it was well outside of my comfort zone, but greasy gears and flying e-clips were sufficiently motivating to keep on going.

Hard parts were mounting and fitting the stepper motor and making the PCB. Have a thread on the RPI and DIY electronic sub forum on my ELS.

Debugging in the shop wasn't that easy, so I built a second board and did most of the debug in my office, which was easier. Certainly made it easier to get the menus working and more functional. When I had something working I would remotely load the lathe PCB and then go down to the shop for live testing. Minor changes were implemented in the shop on a local RPI which had the Arduino IDE installed.

My approach on gearing was to use the QCGB middle setting. That way I could change gearing 2:1 either direction with a minor change of software. No extra pulleys needed, since I would use the gearbox.

I only had a stall once on cutting a 4TPI thread on a 3/4" rod, so rod flex was an issue. The root of the screw was close to 1/4" so insufficient meat. So I'd say I deserved the stall. Also used 4 micro steps per step, which allegedly has more torque than 8. So far, in real use haven't had a stall in over a year. Perhaps this is because I'm a conservative machinist, or because I don't push it too hard, but knock on wood, but it seems to work for me.

I have canned thread tables that allow selection via pressing the pitch value on the display. It's pretty easy to add custom threads of arbitrary pitch. If I wanted to, I could have 3*pi TPI, or 0.23mm, it's relatively straight forward. Weird settings might have some pitch error, but honestly that's no different than using gears. I have a utility program that helps me evaluate things like that. Most of the time the errors are so small, that it practically doesn't matter.

 

[NevNZ]

Interesting control panel- looks Egyptian

Yep it's a busy looking interface. He another one that looks a lot cleaner - pic below. My understanding is that the busy one will also run the cross-slide, and can do things like turning curved surfaces for knobs etc. The simpler looking one just runs the main Z axis carriage.

One feature I like the look of is the soft stops. Apparently you position the carriage, press a button, and it adds a stop to that position which I think would be a nice feature especially when machining close to the chuck or any other hard surface.

@WobblyHand and @RJSakowski thanks for your detailed explanations. I've read more about your installations on other threads and appreciate the detail.

The main question I have in mind at this stage is that Clough 42 uses the TI board because he says it has a very high processing capability which is needed for this application. Maxim has used Arduino, so I wonder if Arduino is just as capable. I have zero knowledge of either, but the videos of both show them to performing similar functions.

 

[DavidR8]

Another option:

Electronic Lead Screw

electronicleadscrew.eu

 

[WobblyHand]

I used a Teensy microcontroller, which I think is a bit more capable than a run of a mill Arduino. Teensy runs at 600MHz and has full floating point math, at no speed penalty. I use a 4096 count spindle encoder (per revolution) it will run without a hitch up to 5800 RPM. Max chuck limit is 3000 RPM, so should have some decent safety factor. Although the Teensy has a hardware quadrature encoder, I didn't use it since it was 32 bit only. My software interrupt driven encoder is 64 bit, so it cannot overflow in any practical circumstances. A Teensy is more than capable for this.

The TI processor was nice for it's time, but isn't as capable. However, James Clough did an amazing job with it, and it's amazing for the board. I used a Teensy because the TI boards were unavailable due to pandemic shortages. I had one on backorder for 6 months and finally gave up and designed a system based on a Teensy. A few months after getting everything working the TI boards became available. At this point, I have no reason to adopt the Clough42 ELS. But right now, his ELS would be the easy button.