Thread: Clough42 Electronic Leadscrew Implementation

I’ve followed Clough42’s ELS project for a while now with great interest.

https://youtu.be/FTs9GygRQ-U

Not only does it make for great YouTube watching but as I have a Hercus 9” C it would solve a couple of huge problems I have with the lathe:

1. The inability to quickly change feed rates. Eg roughing cuts to fine finishing
2. Metric threading

So I’ve finally bitten the bullet and have ordered all the parts to complete the build. I’m just waiting on them all being delivered.

I ordered the control panel and control board from Clough42’s eBay site, the LaunchXL board from Mouser and have a Nema 24 motor on the way from an Australia supplier.

In preparation for making it all fit together I’ve started on some mounts for the stepper motor and the encoder. These are from 10mm steel plate and gave me an opportunity to use my rotary table for the first time.

Nema 24 mount:



I made some nuts for the mounting that use the change gear bracket. I plan to hang the motor off the back:



Plus the encoder mount:



I’m planning on bolting this to the top arm of the change gear bracket but need to make an 8mm bolt with a shoulder still.

The plan is to connect the motor and encoder to the lathe using toothed pulleys. Partly because they are so quiet. I’ve noticed how quiet and smooth the lathe runs without the change gears attached.

Also today I set about trying to get the software downloaded and ready to install on the prototype board. It’s bloody complicated and I fell over on the first hurdle with a “Make” error but I think I managed to solve that by fixing the folder where the code/project was. Time will tell if it loads properly.

Watch this space…

Keep it coming. I'll be interested in how you go.

Another member here Joe Hovel made an ELS some years back for his lathe.

I think it's a cool project.

Simon

Sent from my SM-G970F using Tapatalk

Part 1 arrived this morning. My goodness Mouser are a tight outfit. Delivered in a couple of days!





Now I have to wait for all the other bits to arrive before I can load the software and test to see if it works.

Good luck with the build. Looking forward to watching your progress.

Mouser are great. As are Digi-Key. Free postage from the USA for orders over USD50. Arrrives in less time than a lot of domestic parcels.

More arrivals but unfortunately I don’t have the required parts yet to do a bench test. My motor parts arrived from Steppers Online:

I went with a Nema24 closed loop stepper motor. I’ll also be running a 2:1 reduction on the motor to leadscrew. No idea if that’s correct as I know the steppers lose torque at high RPM, but my lathe tops out at around 1,200 RPM so I can’t see me needing the speed that Clough42 needed for his lathe and I thought the extra torque was better than going with a Nema34 motor.

I can fit a Nema34 (just) if I have to, but I’m hopeful this will work.

It fits the mount perfectly, I just need to pop it in the 4 jaw and bore out the recess for the motor register:



I’ve been trying to understand some motor setup stuff but it’s difficult when you can’t bench test. Anyone here with some stepper motor experience?

My encoder is 1024 with quadrature. So 4096 pulses per revolution.

My leadscrew is 8 TPI

I have the option of setting the steps and micro steps in the software and I have the option to select the pulses per rev on the motor driver.

My assumption is that I need to match the encoder pulses to the motor driver to get a 1:1 drive ratio. Is that correct?

How do I match that when I don’t have 4096 pulses per rev on the motor driver?

I managed to get the motor mount on the lathe tonight and bore out the recess. I got a lump of Alu and drilled the 4 holes in it, then mounted this to the lathe in the 3 jaw. Worked perfectly.

Mounted up and rock solid!



Just need to find a way to clean up the wires. I’m actually going to turn the end of my bench in to an electrical board by putting a sheet of plywood on the end. This will allow me ti mount all the electronics like the leadscrew and VFD and will be hidden away from chips and any other potential sources of problems. I’ll likely out a Perspex sheet over it all to stop and fingers getting in.

Neevo

Thanks for posting this. I am keen to see how it all works out. Is there any chance once it has been done to give an idea of what it ended up costing excluding your time. That is if you are happy to add it up.

Steve

Yeah of course, happy to document the costs. So far it’s cost me:

Clough42 Control panel and power board $100
Texas Instruments Prototype Board $50
Nema 24 motor, driver and power supply $195
Omron Rotary encoder $35
Pair of 3M toothed pulleys $20
Pair of GT2 pulleys $10

The steel plate I had lying around along with the various fasteners.

The only bits left (I think) to buy are the 3M and GT2 belts and they’re cheap as chips.

I’ve been reading that you can do it cheaper as Clough42 produces and uses very high quality parts. But I’d prefer to have quality given the relatively cheap cost vs say trying to retrofit a model A gearbox to my lathe. Even then I wouldn’t have access to metric, imperial, on the fly changes that this solution should give me. Let alone the additional torque and quiet I get from not driving the leadscrew with the main lathe motor.

Thanks for the pricing neevo. At AU$500 or so plus time and material for adapters to me its a project well worth tackling, mine is an AL340. Even at $1000 plus plus its worthwhile.

Story time.
I knew little about lathes when I went to buy my AL340 but I did know from my limited contact with lathes over the years that there was a fair bit of time spent swapping belts and gears.
When I saw that the AL340 had a 'quick change gearbox' I thought you beauty that gets rid of that PITA part of using a lathe.
Only to come back to earth when I discovered that I still had to swap gears (no belt swaps mind you) to change between feeding, metric threads, and imperial threads.
Another first world problem.

I 100% agree. I think for the price it’s actually a very worthwhile upgrade.

Originally Posted by neevo

Anyone here with some stepper motor experience?

My encoder is 1024 with quadrature. So 4096 pulses per revolution.

My leadscrew is 8 TPI

I have the option of setting the steps and micro steps in the software and I have the option to select the pulses per rev on the motor driver.

My assumption is that I need to match the encoder pulses to the motor driver to get a 1:1 drive ratio. Is that correct?

How do I match that when I don’t have 4096 pulses per rev on the motor driver?

Never used a stepper motor, but

1) from Clough's Proof of Concept video, he had "FEED" set to .390?

2) have a read of "My leadscrew isn't turning at the right ratio or my threads are the wrong pitch"
at https://github.com/clough42/electron...roubleshooting

Originally Posted by nigelpearson

1) from Clough's Proof of Concept video, he had "FEED" set to .390?

No expert but, I *think*.......the figure '0.390' represents the relationship between the spindle 'counts' and the leadscrew 'counts' on Clough42's Lathe?
You have to do the calcs for your Lathe to get same result.


I've only watched the first vid so far....looks good. Might be a project in the future for me.....lol

Originally Posted by Sterob

No expert but, I *think*.......the figure '0.390' represents the relationship between the spindle 'counts' and the leadscrew 'counts' on Clough42's Lathe?
You have to do the calcs for your Lathe to get same result.

On a finished setup, yes. That video was just demonstrating encoder driving the stepper 1:1.


So, a 1.8° motor has 200 steps/rev. Divide 200 by 0.39, and you get 512.82pulses - close to a divisor of the 1024 pulse encoder he used.

(and multiplied by 8tpi, 4102.56 - close to the 4096 quadrature pulses.
Note that .391 would give 511.5 and 4092 - even closer !
Perfect ratio would be .390625.

Buying a 400, 600 or 1000 ppr encoder makes it easier)

Thanks gents! What I needed regards to info and also thanks for the link to the Clough42 questions section (Nigel), I hadn’t seen that before.

I copied Clough42 a bit too much and I’m hindsight I would have gotten the 1000 encoder vs the 1024. But I’m sure I’ll get it working with minimal error, certainly over a 1-2 inch thread.