Lathe Stepper Motor Power Feed Mod

[hedgywah]

Check out Clough42 on YouTube. He did a video series documenting his build. He also released code and some helpful bits to make it easier to replicate. Even if you don't use the same equipment, it can help give you ideas. There are a few build threads here on it as well.

I wouldn't have thought about belt driving the handwheel. Turned out nice!

Thanks for the kind words brother! It took a few iterations to get here. My first try was to directly drive the spur gear driving the carriage down the pinion using a worm gear but had trouble figuring out a good coupling strategy for a gear connected to that shaft. Would have been a little less “slapped on the front of the apron” but this turned out to get me what I was after anyway.

And I’ll check out his videos, maybe watched a handful of his before and they’re always really informative.

 

[hedgywah]

I picked a Teensy 4.x for my ELS. It has a 600MHz clock and lots of processing power. I didn't want my ELS to lock up or crash while I was using it. Under $30 for the processor and definitely does the job. It's also running a touch panel display and displays my DRO's without breaking a sweat. User interface is via the touchscreen and soft buttons (context sensitive programmable). There's several threads on ELS systems on Hobby Machinist, including mine. Worth a read before jumping in head first!

Good thinking, I have a Teensy LC, but I love your idea for a touch panel that also displays DRO and might just work towards that. I have a raspberry pi 3b+ that should do the trick! I’m a little new to navigating this forum yet- if you have time do you mind linking your post ?

 

[WobblyHand]

Good thinking, I have a Teensy LC, but I love your idea for a touch panel that also displays DRO and might just work towards that. I have a raspberry pi 3b+ that should do the trick! I’m a little new to navigating this forum yet- if you have time do you mind linking your post ?

Mine is: https://www.hobby-machinist.com/thr...ad-screw-controller-using-a-teensy-4-1.99609/ My thread was documenting my journey figuring out what was needed -- and then doing it. I designed my own PCB and wrote my own software from scratch, based on the Bresenham algorithm. Still have some PCB's floating around.

Many ELS implementations use a variation of Bresenham for determining how to move the lead screw. Some folks have implemented displays on their phones, but I'm not that good of a programmer. So I went for a simple touch panel display. In my opinion, the human interface was far more complicated than the ELS motion control system. There's 3x as much code in the user interface than in the control. I think a Teensy LC is under powered for this application. The (software) quadrature encoder on the Teensy 4.1 will process the encoder edges up to 250 KHz for the spindle, and handle the DROs. FYI, you can use the same quad encoder algorithm for the DROs.

Here's an interesting thread using a Pi Pico. https://www.hobby-machinist.com/threads/another-electronic-lead-screw-using-the-pi-pico.111195/
I think there was an earlier one on the Pi Pico, but it never completed to my knowledge.

If you search using the string "Electronic Lead Screw" you will find quite a few links. Many are using James Clough's "Clough42" ELS that he popularized. Lots of very good reading material.

 

[hedgywah]

Mine is: https://www.hobby-machinist.com/thr...ad-screw-controller-using-a-teensy-4-1.99609/ My thread was documenting my journey figuring out what was needed -- and then doing it. I designed my own PCB and wrote my own software from scratch, based on the Bresenham algorithm. Still have some PCB's floating around.

Many ELS implementations use a variation of Bresenham for determining how to move the lead screw. Some folks have implemented displays on their phones, but I'm not that good of a programmer. So I went for a simple touch panel display. In my opinion, the human interface was far more complicated than the ELS motion control system. There's 3x as much code in the user interface than in the control. I think a Teensy LC is under powered for this application. The (software) quadrature encoder on the Teensy 4.1 will process the encoder edges up to 250 KHz for the spindle, and handle the DROs. FYI, you can use the same quad encoder algorithm for the DROs.

Here's an interesting thread using a Pi Pico. https://www.hobby-machinist.com/threads/another-electronic-lead-screw-using-the-pi-pico.111195/
I think there was an earlier one on the Pi Pico, but it never completed to my knowledge.

If you search using the string "Electronic Lead Screw" you will find quite a few links. Many are using James Clough's "Clough42" ELS that he popularized. Lots of very good reading material.

Highly appreciated bro! Looks like my November project is about to be in full swing! My background is in electronics engineering so this is starting to feel like home, but I’ll be darned if I haven’t always hated UI/UX design… so much code dedicated to poka yoke. I’ll put your links to work!

 

[WobblyHand]

Highly appreciated bro! Looks like my November project is about to be in full swing! My background is in electronics engineering so this is starting to feel like home, but I’ll be darned if I haven’t always hated UI/UX design… so much code dedicated to poka yoke. I’ll put your links to work!

EE myself. If you have questions, just ask...

My ELS took about 6 months to work, and a few more months to clean up some stuff. Was a lot of fun to do. Still gives me great pleasure when running the lathe, since it was my handiwork. Taught myself KiCAD to design the PCB. Got the board fabbed. Designed the housing using FreeCAD and printed the case. Wrote the code using the Arduino IDE and used a bunch of the Teensy libraries - like the timer and the encoder libraries. I did struggle with the UI, that came hard to me. Finally, I rewrote parts of the code so it would be a state machine, and that made it a lot easier to develop.

Still need to add some features, but haven't had the time lately. I did branch the code for this purpose, to keep things clean, and to play in my separate sandbox. Hope to get back to that sometime soon.

 

[hedgywah]

Very cool, Sounds like you and I come from a similar background. Haven't used KiCAD yet, but very familiar with Teensy and Arduino, designed a few PCB's in Eagle and Multisim/Ultiboard and fabbed them using transparencies over photosensitive copper, mostly music gear. It really is hard to beat using a tool or system that you made yourself

EE myself. If you have questions, just ask...

My ELS took about 6 months to work, and a few more months to clean up some stuff. Was a lot of fun to do. Still gives me great pleasure when running the lathe, since it was my handiwork. Taught myself KiCAD to design the PCB. Got the board fabbed. Designed the housing using FreeCAD and printed the case. Wrote the code using the Arduino IDE and used a bunch of the Teensy libraries - like the timer and the encoder libraries. I did struggle with the UI, that came hard to me. Finally, I rewrote parts of the code so it would be a state machine, and that made it a lot easier to develop.

Still need to add some features, but haven't had the time lately. I did branch the code for this purpose, to keep things clean, and to play in my separate sandbox. Hope to get back to that sometime soon.

 

[WobblyHand]

Very cool, Sounds like you and I come from a similar background. Haven't used KiCAD yet, but very familiar with Teensy and Arduino, designed a few PCB's in Eagle and Multisim/Ultiboard and fabbed them using transparencies over photosensitive copper, mostly music gear. It really is hard to beat using a tool or system that you made yourself

I had two lots of boards made, 5 from each vendor. JLCPCB was cheaper and faster. They are professionally made four layer boards. Two wiring layers and two power planes. The other guys were more expensive, but not terrible. Both lots are 100% usable and indistinguishable in use.

As I recall, as a new customer, with my discounts and shipping, the JLC boards cost a whopping $7. That's $7 for 5 100x95mm boards and that included "slow boat" shipping. Took 2.5 weeks to receive them. Have no idea what they'd cost today (two years later). Haven't found a need to re-spin the boards, they work fine with no rework. I thought for sure I'd need a re-spin, as I versioned it 0.1 on the silk screen. I was pleasantly surprised that I didn't have to make any changes.

Here's SN0001. My test mule. I tested the software at my desk, before putting it on the machine. Very useful for the UI stuff. It's not a sophisticated board, but it was my first KiCAD project. The mechanical board design was done in FreeCAD along with the printed housing.

 

[hedgywah]

I had two lots of boards made, 5 from each vendor. JLCPCB was cheaper and faster. They are professionally made four layer boards. Two wiring layers and two power planes. The other guys were more expensive, but not terrible. Both lots are 100% usable and indistinguishable in use.

As I recall, as a new customer, with my discounts and shipping, the JLC boards cost a whopping $7. That's $7 for 5 100x95mm boards and that included "slow boat" shipping. Took 2.5 weeks to receive them. Have no idea what they'd cost today (two years later). Haven't found a need to re-spin the boards, they work fine with no rework. I thought for sure I'd need a re-spin, as I versioned it 0.1 on the silk screen. I was pleasantly surprised that I didn't have to make any changes.

Here's SN0001. My test mule. I tested the software at my desk, before putting it on the machine. Very useful for the UI stuff. It's not a sophisticated board, but it was my first KiCAD project. The mechanical board design was done in FreeCAD along with the printed housing.
View attachment 508217View attachment 508218

Dude I love this! That Assembly turned out so clean! I will have to keep that vendor in mind bc I’d gladly pay $7 to avoid burning my nose hairs off with ferric chloride again

 

[WobblyHand]

Dude I love this! That Assembly turned out so clean! I will have to keep that vendor in mind bc I’d gladly pay $7 to avoid burning my nose hairs off with ferric chloride again

That's why I mentioned it to you. Really had a good experience with JLCPCB. Actually, had a good experience with the other vendor as well.

But I sweated the PCB design. I had never used KiCAD for a design, I had to learn the tool. That took about a week. The DRC was painful working through the errors. But the result was a first pass success. The hero was the KiCAD software, really. After going through the process, I made the design package and KiCAD created the Gerber files and the silkscreen info. That zip file was sent to JLCPCB, and a quote was generated. From submittal of the files to receiving the boards was around 2.5 weeks. Compared to the breadboard I made earlier, with all it's intermittent connections, this was heaven.

The last time I had done a PCB design was more than 40 years ago, as a junior engineer. (It was a first pass success, too. I took longer in the design phase, and management was hounding me daily. They weren't complaining later when my boards required no debug, nor rework. I took 6 weeks off their schedule, because I did it right the first time. Software development wasn't ready for my boards. They weren't expecting me to be done so soon!)

 

[hedgywah]

That's why I mentioned it to you. Really had a good experience with JLCPCB. Actually, had a good experience with the other vendor as well.

But I sweated the PCB design. I had never used KiCAD for a design, I had to learn the tool. That took about a week. The DRC was painful working through the errors. But the result was a first pass success. The hero was the KiCAD software, really. After going through the process, I made the design package and KiCAD created the Gerber files and the silkscreen info. That zip file was sent to JLCPCB, and a quote was generated. From submittal of the files to receiving the boards was around 2.5 weeks. Compared to the breadboard I made earlier, with all it's intermittent connections, this was heaven.

The last time I had done a PCB design was more than 40 years ago, as a junior engineer. (It was a first pass success, too. I took longer in the design phase, and management was hounding me daily. They weren't complaining later when my boards required no debug, nor rework. I took 6 weeks off their schedule, because I did it right the first time. Software development wasn't ready for my boards. They weren't expecting me to be done so soon!)

Ohh so we have been mortal enemies lmao, I was a test engineer in charge of signing off NPI on a third generation product. Might have angered a designer or two by constantly requesting board revisions to add coverage for flying probe :x, but in fairness it did pay off once production ramped up and we all played nice together lol
Recently I was contracted to develop and deliver a test fixture for a lab in 8 weeks or less. Wish I had known about your PCB service then but I’m honestly amazed the breadboard protoboard is still holding up after 6 months