electronic lead screw

[Autodidact]

You found me. I don't have any backlash compensation because it's not CNC, just a programmable "gearbox". The number of pitch selections is arbitrary. I've implemented every pitch that I could find in online pictures of lathes, and every tap available from McMaster-Carr. I stopped short of having an arbitrary programmable option, but it would be possible. I did limit it to 4tpi just because I have a small lathe. That's getting to be some serious depth of cut, and I have already noticed some "hiccups" cutting an 8tpi Acme thread in 1144. I'm waiting for more timing pulleys and belts so that I can gear it down from the current 4:1 ratio between the stepper and the screw. I'm planning to test it at 5-, 6- and 8-to-1.

I still have more to do. The touch screen is great for a lot of things, but on-the-fly feed direction control needed something more tactile, so I've added a toggle switch mounted in front of the headstock. I quickly programmed it to control the direction, but have to add jogging support still. I just got sidetracked by actually making some things.

I think it would be cool to do cut knurling, so I'm also thinking of adding support for multi-start threads, but that's a ways off yet. I've only used half the RAM on the Mega so far, so there's still room to squeeze more features in . I promise to make at least a basic version of the code available at some point when I'm satisfied with it.

-Jon
[/QUOTE

You found me. I don't have any backlash compensation because it's not CNC, just a programmable "gearbox". The number of pitch selections is arbitrary. I've implemented every pitch that I could find in online pictures of lathes, and every tap available from McMaster-Carr. I stopped short of having an arbitrary programmable option, but it would be possible. I did limit it to 4tpi just because I have a small lathe. That's getting to be some serious depth of cut, and I have already noticed some "hiccups" cutting an 8tpi Acme thread in 1144. I'm waiting for more timing pulleys and belts so that I can gear it down from the current 4:1 ratio between the stepper and the screw. I'm planning to test it at 5-, 6- and 8-to-1.

I still have more to do. The touch screen is great for a lot of things, but on-the-fly feed direction control needed something more tactile, so I've added a toggle switch mounted in front of the headstock. I quickly programmed it to control the direction, but have to add jogging support still. I just got sidetracked by actually making some things.

I think it would be cool to do cut knurling, so I'm also thinking of adding support for multi-start threads, but that's a ways off yet. I've only used half the RAM on the Mega so far, so there's still room to squeeze more features in . I promise to make at least a basic version of the code available at some point when I'm satisfied with it.

-Jon

Did you end up making the knurling code? I spent a fair amount of time programming a Mega as a control system and found it fairly capable.

 

[greenail]

Did you end up making the knurling code? I spent a fair amount of time programming a Mega as a control system and found it fairly capable.

How would you imagine the knurling would work? If it is just like a multistart thread I don't think it would be that hard. I have start synchronization working in my ELS project now.

 

[Hard_ware]

Nice!!! plus multiple sync points +1
A wired pendant or control box interface would be nice once you get things worked out using gui.

The ELS to avoid changing gears is ok if changing gears bothered you.
I think the benefit of the els is not cranking a carriage handle.
If I didn't want to crank any handles then full CNC is the ticket.
The ELS being sync'd to the spindle is a must.
Closed loop stepper motors, 3-phase for position measurement.
Having a start position and a stop position would be a must.
Having a return to start button would be great. A manual L and R feed(speed adjustable) to cut or set start and stop points.

If you think about what motions you do on the lathe, to face you crank the cross slide, after that is turning , move cross slide to start point and start turning cut, stop back out or not, move carriage back to start and repeat.
With a small lathe you can't make deep cuts, so it's repeat repeat repeat.
Cutting threads all day and different threads constantly I don't buy it.
Depending on what you make it's usually a handful of different threads you will ever cut.
So making an electronic lead screw and cost vs 3 min to change gears for a thread pitch is more of a novelty then time saver.
Only exception is cutting Metric on Imperial LS or vice versa, not being able to disengage and reengage the LS sucks and slows the process down.
But turning will be used for every part you make on the lathe.
Imagine pressing a button go then return then crank cross slide in a bit now press go then return button and turn in a bit.
Not much cranking. With TouchDRO you just line up the green crosshair with your saved targets in your workspace set start and stop on the ELS and off you go. Correlating the stepper position counters to a absolute calibrated position like a DRO, start and stop points could be entered on the Z axis from prints or TouchDRO workspace.

https://imgur.com/QULIva7

Having a set start point and set stop point and a go/return, only cross slide needs to be turned in each pass for depth of cut.
If you need to set a new start point bump the L or R and set it.

This paired with touch DRO graphic workspace is about as far as you could go short of full CNC.
One knob on the lathe to crank

Teensy4.0 look like a beast!

PS we have the same lathe 8x16 38mm bore.
I made a gear chart for gear combo's, I cut 24 and 28 TPI no problem.
1mm all day long as you can't screw it up with a metric lead screw

 

[Qtron]

How would you imagine the knurling would work? If it is just like a multistart thread I don't think it would be that hard. I have start synchronization working in my ELS project now.

Hello Greenail, hope ur well, hows it all going.. Any updates?

 

[greenail]

Hello Greenail, hope ur well, hows it all going.. Any updates?

I've been working on my grinder and my new CNC build. No big updates but I have one person getting his lathe setup and I should be getting some feedback soon. I've been using my setup regularly and it is working great with a few things to note.

1. quick and easy way to turn off the stepper is handy if you have a hand wheel on your lead screw.
2. my encoder gear turned out to be the wrong tooth count (missed it by 2) so I need to print a new one before I start thread testing again.
3. the design of the haptic controller communication interface stalled me out a bit since I don't really know what it should look like.
4. While the haptic controller idea is fun it actually doesn't need a physical controller, controlling it via a phone or tablet works great.

I'll likely start writing more code and adding features when I get feedback from the new user or when I need to turn some threads. if anyone wants to help out with testing they may want to check out the setup thread here. https://github.com/jschoch/ESPels/issues/4

 

[greenail]

I need to make an adapter for my NSK ATC spindle and thus I need to cut some threads which leads me back into working on my ELS. Looking for some feedback.

This page has a good overview of the different threading strategies used in CNC threading: http://www.mitsubishicarbide.com/en...ing/tec_threading_guide/tec_threading_methods


To sum it up the ELS should offset the cutter based on the strategy, however since there may be no X feeding the threading depth is somewhat arbitrary. My current thinking is for the user to enter the number of passes they want and for the user interface to display a table showing the infeeds based on the number of passes and rely on the user to tell the ELS when he has moved to the next pass. So for example:

1mm thread pitch, 4 passes, strategy flank:

Pass 1: infeed .3mm radius, offset: 0
Pass 2: infeed .16, offset .25
Pass 3: infeed .12, offset .5
Pass 4: infeed .11, offset .75

Is this confusing?

 

[Qtron]

You found me. I don't have any backlash compensation because it's not CNC, just a programmable "gearbox". The number of pitch selections is arbitrary. I've implemented every pitch that I could find in online pictures of lathes, and every tap available from McMaster-Carr. I stopped short of having an arbitrary programmable option, but it would be possible. I did limit it to 4tpi just because I have a small lathe. That's getting to be some serious depth of cut, and I have already noticed some "hiccups" cutting an 8tpi Acme thread in 1144. I'm waiting for more timing pulleys and belts so that I can gear it down from the current 4:1 ratio between the stepper and the screw. I'm planning to test it at 5-, 6- and 8-to-1.

I still have more to do. The touch screen is great for a lot of things, but on-the-fly feed direction control needed something more tactile, so I've added a toggle switch mounted in front of the headstock. I quickly programmed it to control the direction, but have to add jogging support still. I just got sidetracked by actually making some things.

I think it would be cool to do cut knurling, so I'm also thinking of adding support for multi-start threads, but that's a ways off yet. I've only used half the RAM on the Mega so far, so there's still room to squeeze more features in . I promise to make at least a basic version of the code available at some point when I'm satisfied with it.

-Jon

Hi Jon,
Lost contact w you;
Hope U are well..and not snowed under!
Any ELS updates since we spoke abt 6 months ago?
Cheers,
Qtron

 

[Qtron]

I need to make an adapter for my NSK ATC spindle and thus I need to cut some threads which leads me back into working on my ELS. Looking for some feedback.

This page has a good overview of the different threading strategies used in CNC threading: http://www.mitsubishicarbide.com/en...ing/tec_threading_guide/tec_threading_methods


To sum it up the ELS should offset the cutter based on the strategy, however since there may be no X feeding the threading depth is somewhat arbitrary. My current thinking is for the user to enter the number of passes they want and for the user interface to display a table showing the infeeds based on the number of passes and rely on the user to tell the ELS when he has moved to the next pass. So for example:

1mm thread pitch, 4 passes, strategy flank:

Pass 1: infeed .3mm radius, offset: 0
Pass 2: infeed .16, offset .25
Pass 3: infeed .12, offset .5
Pass 4: infeed .11, offset .75

Is this confusing?

Offset = ?

 

[greenail]

I need to make an adapter for my NSK ATC spindle and thus I need to cut some threads which leads me back into working on my ELS. Looking for some feedback.

This page has a good overview of the different threading strategies used in CNC threading: http://www.mitsubishicarbide.com/en...ing/tec_threading_guide/tec_threading_methods


To sum it up the ELS should offset the cutter based on the strategy, however since there may be no X feeding the threading depth is somewhat arbitrary. My current thinking is for the user to enter the number of passes they want and for the user interface to display a table showing the infeeds based on the number of passes and rely on the user to tell the ELS when he has moved to the next pass. So for example:

1mm thread pitch, 4 passes, strategy flank:

Pass 1: infeed .3mm radius, offset: 0
Pass 2: infeed .16, offset .25
Pass 3: infeed .12, offset .5
Pass 4: infeed .11, offset .75

Is this confusing?

here's the new table display for threading without a compound.

Getting close to releasing a beta, let me know if you want to test it out.

 

[Qtron]

here's the new table display for threading without a compound.

Getting close to releasing a beta, let me know if you want to test it out.

Fantastic Greenail look FWD to end result.
But will need info like how the tablet connects to the control board etc. Marvellous!
U have taken ELS into 21st century with cream on top! Cheers
Agree re no topslide extra stabilty too, esp on my old clunker.

i suppose the entire lines of offset & incremental feed & Total feed decimal places will be truncated on the display to
not dazzle the user?