New Electronic Leadscrew Project

[Paul Alciatore]

This looks promising. I like his thinking.

https://www.youtube.com/watch?v=FTs9GygRQ-U

[Sparky_NY]

This looks promising. I like his thinking.

https://www.youtube.com/watch?v=FTs9GygRQ-U

Electronic leadscrews are very old news for lathes. There have been countless build projects and forum threads on the subject over the years. The concept is sound. This guy is not developing any thing new, far from it.

This guy sounds like he has plans for a commercial product in the future, not just a one-off for his lathe. A commercial product is a different matter, there are so many hardware configurations for the different lathes out there that every install will be unique (hardware wise) When developed, the cost of a commercial product will likely be beyond what most will be wiling to pay.

As I said, electronic leadscrews are old news YET no commercial products have seem to appeared over the years. There is probably good reasoning for that.

[Doozer]

I am also interested in buying (or making) an ELS for my lathe.
For me, I am pretty good with electrical and electronics, but I
just don't have the "hobby" time to make my own boards and
solder in 100+ components. So I would like to buy one.
One product that I have bought for a CNC lathe that I made
was the servo motor and drive package from AutomationDirect.
If you look on their site, you can get them in different Watt ratings,
which is horsepower. You get to buy the motor and matching cable
that plugs into their drive. You also buy an encoder (for attaching
to the lathe spindle) and it also had a cable that plugs into their drive.
The drive connects to a laptop and they give you software to setup
the drive parameters. There are 2 parameters, which are a fraction
ratio that you can input. This ratio is the setup between the input from
the encoder, and the output to the motor. (The motor you would connect
to the leadscrew). So 1 to 1, the leadscrew will spin the same speed
as the spindle. You need to figure your math to cut whatever threads per
inch or millimeter pitch that you want, so there is some manual math
needed to find what ratio you need to input into the drive. (Example,
1:1 ratio, the lathe will cut threads that match the pitch of the leadscrew,
and from there adjust your math accordingly.) Pretty easy to calculate,
no sexy front end screen with this drive, just manually input 2 numbers
for the lead-follower fraction. But I thought it was a highly usable option
for a purchased ELS system for the home shop. I do not know much
about the Raspberry Pie, but I think it is a small computer. Thinking it
might be able to run the servo drive software in a neat little package,
without the need to have a laptop always sitting near your lathe.
What I do know, is that AutomationDirect does sell these servo drive
and motor packages for around $600 to $800 and they work very well.
At least the lathe I built with them, it was a good fit for the application.
Maybe for you cheap home shop bastards, the price might seem a
little bit high, but having used one, I can assure you that the Automation
Direct motors and drives work well and are not difficult to program.
I know it seems like a lot of money to outlay on a possible unknown
where you have to rely on yourself to sort out the details, but the
CNC conversion guys do this every day. I am just here to testify that
their servo drive works and it is nice to have a motor and an encoder
that will plug directly into their drive and it works. No figuring out pins
and wire connections. That is worth something to me. Actually I called
AutomationDirect once, an asked if I could program the ratio in their
servo drive software using one of their touch screens, without connecting
the touch screen to a PLC first. They told me yes, that they offer a touch
screen that would plug the numeric values into the drive software, and no
need to go through a PLC, but you could not do much math with the touch
screen alone, just enter the variables. With a PLC you could do the math
like enter the TPI and it puts in the ratio for you, but it would be another
piece of hardware to buy. The Babin ELS on the Hardinge lathes uses
a touch screen with a PLC built in to do what they do. The Babin touch
screen is not from AutomationDirect. It is another brand. I looked into
it at one time, and I figured out what Babin uses for a screen, but I forgot
what exactly which one it was.
When I get some time, I am going to buy another AutomationDirect servo
drive and motor and encoder, and convert one of my toolroom lathes
for ELS. If any of you guys have some ideas, I will be watching this thread.

--Doozer

[CCWKen]

I'd buy one although I don't think I'd pay $600 for it. That would buy a lot of the taps and dies I use now. And keeping stock around for off-the-shelf parts like special boring head mounts seeps wasteful. My change gears stay on my favorite feed. I would like to change that on the fly.

[BCRider]

After watching about half that video I feel a serious urge to go out to the shop and give the full featured thread or feed QCGB on my lathe a hug....

[lakeside53]

I followed the original ELS project (was a yahoo group) for years, and came to the conclusion that although was interesting at the time, today you may as well just CNC the entire lathe by adding in the second axis. Use a simple conversational interface if the "programming" seems "daunting".

[nickel-city-fab]

Was gonna say, isn't this basically what the Hardinge HLVH does with analog electrics? I imagine designing the analog way would be much easier/fewer components, for me anyway. At the end of the day, its all math.

[skunkworks]

I agree with lakeside... Linuxcnc has had encoder threading for 15 years or more. I just works. Lead-in and lead out plus tons of other functionality...

Reminds me of this

https://www.youtube.com/watch?v=D_aGsBCorww

'I picked a cnc controller that doesn't thread - so I added threading with an arduino...'

sam

[elf]

I don't know what the big deal about an ELS is. All you need is synchronized steppers (or servos). My rose engine can do threads with any pitch, multi-start threads, left hand, right hand, or just plain helixes. It's driven with a Teensy microprocessor (Arduino compatible). A library, TeensyStep, does the synchronization. My code just needs user input for number of revolutions and length to thread. I also designed the driver board that holds the Teensy and four stepper drivers.

[RB211]

Yep, might as well go full CNC.

[Baz]

Yep, might as well go full CNC.

Anyone here own a bicycle? Why? You might as well get a 6x6 100ton dump truck for moving the groceries or an F1 racer if in a hurry.
An ELS can potentially be a substitute for a pile of gears (cost and hassle) or a complex QCGB (eg Harrison M300 one seen on ebay for £750) but stepper and psu and processor costs do mount up so full CNC does get expensive.
I got a little Arduino last year with the intention of doing an ELS and schemed the software but then got waylaid. Two aspects that I planned were
a) no screen and fiddly menus - use two rotary 16way BCD switches so I can go from thread to feed in one second flat. (trouble is they are expensive)
b) don't try to do any maths in the mini processor. Work it out beforehand and just have lookup tables. No danger of lost cycles.

[RB211]

Anyone here own a bicycle? Why? You might as well get a 6x6 100ton dump truck for moving the groceries or an F1 racer if in a hurry.
An ELS can potentially be a substitute for a pile of gears (cost and hassle) or a complex QCGB (eg Harrison M300 one seen on ebay for £750) but stepper and psu and processor costs do mount up so full CNC does get expensive.
I got a little Arduino last year with the intention of doing an ELS and schemed the software but then got waylaid. Two aspects that I planned were
a) no screen and fiddly menus - use two rotary 16way BCD switches so I can go from thread to feed in one second flat. (trouble is they are expensive)
b) don't try to do any maths in the mini processor. Work it out beforehand and just have lookup tables. No danger of lost cycles.

You are only 1 ballscrew and stepper away from full cnc. Might as well go all the way.

[DFMiller]

I can see this is a useful project.
For instance if your trusty lathe develops a problem like a busted fibre gear all of a sudden and you can’t just run out and get a new gear.
In fact my nice older Taiwanese Myford clone did exactly that yesterday. If the gear turns out to be unobtainium I will be looking at this or something similar.

Dave

[RB211]

I can see this is a useful project.
For instance if your trusty lathe develops a problem like a busted fibre gear all of a sudden and you can’t just run out and get a new gear.
In fact my nice older Taiwanese Myford clone did exactly that yesterday. If the gear turns out to be unobtainium I will be looking at this or something similar.

Dave

3D print a gear or make one, this is a home shop machinist forum, right?

[DFMiller]

Or make and ELS.
All are options. I suspect ELS is more versatile and much simpler and reliable.