[keen]

Hi guys - just realised this thread should have the perfect followers for my question. Please read this.

I want to know how feasible it would be to convert a manual lathe to cnc and Pathpilot. I have an 1100 mill - and so have the software already, and I gather I can buy a Mesa and do an install in an old xp computer. I have done this before.

I gather I would need an encoder for the spindle and convert the three phase motor set up to a VFD? Fit ballscrews and steppers on the X and Z, drivers, main board, etc.

My main question is - is there any major issues, that would make it a dead end road for me? I have no problems with the mechanical, but can't handle too much complex software IT stuff.

Keen

[brianbonedoc]

Keen - I have seen your videos and based on those I'm sure you can handle it. There's nothing really special per se but there's a bit of tweaking to do on the software side. There's enough help and experience here and on the linuxcnc forums to get you there.

I just did my grizzly lathe in pathpilot. Using the cnc4pc c35 breakout board allowed me to use the tormach flash file and simplifies things.

[Tkamsker]

hi keen i guess you even can do it without mesa card i have seen a video where one guy did it plain on printer port i look at that after christmas


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[keen]

Keen - I have seen your videos and based on those I'm sure you can handle it. There's nothing really special per se but there's a bit of tweaking to do on the software side. There's enough help and experience here and on the linuxcnc forums to get you there.

I just did my grizzly lathe in pathpilot. Using the cnc4pc c35 breakout board allowed me to use the tormach flash file and simplifies things.

Thanks and good to hear you have already done it. A couple of questions please, that are key to this feasibility study.

Both my manual lathes have 3 phase motors - (although I have a spare big single phase motor about 3.5 hp I think) . Can I get some sort of drive that will control them -- (about 5 hp ) - That would work with the standard electronics?
....or would I need to buy a new motor and drive.... or smaller motor and drive ?

- Can I fit the encoder on the lathe spindle - so that I can still use the headstock gearbox to get a speed range to suit the job?

I could buy in a Tormach Slant Pro lathe - but the current exchange rate and freight mean about 20K NZ - and I would have to sell one of my manual lathes to make room for it - (hence the obvious question).

cheers Keen

[keen]

hi keen i guess you even can do it without mesa card i have seen a video where one guy did it plain on printer port i look at that after christmas


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Thanks - But I thought the Mesa greatly improves the performance.?

Keen

[PCW_MESA]

Thanks - But I thought the Mesa greatly improves the performance.?

Keen

You can do all the same things with a parallel port as you can with more sophisticated
hardware, that is, threading, rigid tapping, probing etc. These all work fine with just a parallel port.

( one of the nice features of LinuxCNC's real time design )

The advantages of using hardware step generation and hardware encoder counters
(Mesa FPGA card or other add-on Linuxcnc compatible hardware) are these:

Cleaner step pulse stream ( less jitter and beats between the thread rate and step rate )
This allows a somewhat higher rapids step rate before stalling

Ability to use high resolution encoders ( 5000 line or more are OK )

Less dependence on host CPU having good real time latency (not so picky about PC used)

[andypugh]

Both my manual lathes have 3 phase motors - (although I have a spare big single phase motor about 3.5 hp I think) . Can I get some sort of drive that will control them -- (about 5 hp ) - That would work with the standard electronics?

Yes, you can use a VFD to drive the motors at variable speed, or simply operate the motors as they work now, using electronic control of the contactor, and use the gearbox to set the desired speed.
....or would I need to buy a new motor and drive.... or smaller motor and drive ?

Can I fit the encoder on the lathe spindle - so that I can still use the headstock gearbox to get a speed range to suit the job?

Yes, in fact that is where the encoder needs to be for threading to work properly.
It needs to be driven 1:1 by the spindle, and this can be done in a number of ways, pulleys, gears or an encoder disc with a large centre hole.
An alternative is to use one of the spindle gears and some magnetic pickups as an encoder. https://pico-systems.com/bridge_spindle.html

I would suggest not getting too hung-up on using PathPilot initially, normal LinuxCNC can run a lathe perfectly adequately, and is likely to be easier to get working with your system.

The hard part of converting a lathe is the X-axis drive. There isn't usually room in the cross-slide for a ballnut, to creative solutions are often needed.
Having said that, backlash compensation in software is a lot more likely to work with a lathe than a mill, as the cutting forces almost never reverse during a cut.

[keen]

Thanks heaps for your input guys - most helpful.

Thanks for the warning about the X ballnut - yes I see your point, because the lathe design is condensed here to allow the max swing - what sort of creative solutions work well? A higher cross slide ?(this would allow a longer one also)

Just checking this point. I can set the lathe in eg a mid range gear for a job to get the torque and revs needed, then the electronics looped back with the encoder will dive the VFD which controls the existing motor speeds and reversing it out if a rapid stop is needed etc.

keen

[andypugh]

what sort of creative solutions work well? A higher cross slide ?

You can just use a small ballnut. My lathe has been using an 8mm which looks pitiful, but has given to trouble at all:
http://www.cnczone.com/forums/mini-l...tml#post509784
Putting the thrust-bearings outboard, where the micrometer dial normally are, made it easier.
Another alternative (if there is room) is a rotating ball-nut arrangement at the back of the lathe, which allows you to fit a bigger screw. (I didn't have room, because of the milling head).

There is a nut for a 16mm screw that is unusually slim, but has a ball return rube. That is what I used on my milling machine, and I plan on an equally elaborate mounting block for my lathe conversion:
http://www.cnczone.com/forums/vertic...ml#post1393132

Details of my own ongoing lathe conversion here:
Bodgesoc Blogsoc: Holbrook Minor Single Phase Conversion

Just checking this point. I can set the lathe in eg a mid range gear for a job to get the torque and revs needed, then the electronics looped back with the encoder will dive the VFD which controls the existing motor speeds and reversing it out if a rapid stop is needed etc.

Yes. It is even possible to have the machine automatically detect which gear is engaged by comparing the VFD speed and the encoder speed.

[tmarks11]

bump

[Steve Seebold]

I asked because I know someone who has switched to Path Pilot and is having all kinds of problems with it.

He's having problems when he gets up to G59. He says it doesn't like the tool changer. He asks me questions about it and I have to tell him if I'm not standing in front of the control I can't help him.

[tmarks11]

You know there is an entire sub-forum in this group dedicated to Path Pilot? Send him there and he can ask away.

http://www.cnczone.com/forums/tormach-pathpilot-/

[HIKARURD]

I'm working on a G0602/Pathpilot conversion and would love if someone has a config they can share?
I'm interested in learning the details of what has to be done to an existing linuxcnc config to make it work with pathpilot and examples help allot.
From what I can tell really the ini file doesn't need any changes, it's all in the hal files and specifically mapping things to the tormach variables.

I think I'm getting a grasp on Linuxcnc (far from pro though) but enough this will help complete my understanding

TIA
Sandra

[brianbonedoc]

Sandra - no problem. I have been through this and so have several others. Here are my config files for the Grizzly. I am using a C35 CNC4PC breakout board and a C41 speed control. The stepper drivers are Automation Technology KL-5056Ds.

I will try to help any way I can just let me know.

[HIKARURD]

Sandra - no problem. I have been through this and so have several others. Here are my config files for the Grizzly. I am using a C35 CNC4PC breakout board and a C41 speed control. The stepper drivers are Automation Technology KL-5056Ds.

I will try to help any way I can just let me know.

Thank you for that.
Took a look through it, already many things are clearer already.
You really are just connecting to the pathpilot GUI, the rest is normal LinuxCNC setup. which makes sense, no mater which GUI you use you're doing the same thing.
Just Tormach decided to change names of some things and added some is all.

I wonder how hard it would be to get most of it back to standard LinuxCNC naming conventions. once there you should be able to diff it then come up with a patch file to apply
or script it to apply changes to updates to pathpilot.

and FYI, I am on the LinuxCNC forum pathpilot group, just didn't see anyone there working with a g0602 in the forum so googled and found this post and your work

also, my setup is a 5i26/7i76 combo with Leadshine DM856 drivers and a GM2 VFD.
I'm putting my electronics panel together now. it's been tested just getting it all together properly.

[brianbonedoc]

Sandra I think u are correct for the most part - but there are a lot of nuances and PathPilot is very finicky - one small error and it won't boot. It is much easier to start with a standard PP install and tweak it - rather than with a standard linuxcnc and force it to become PP.

[HIKARURD]

That is my plan.
Pulling the items needed out of the LinuxCNC ini and hal files and put into the PP ones
I won't have a tool changer other than myself so setting PP to manual tool change should take care of that.
the steppers are easy as are the home/limits.

I think the Mill is harder due to the way they multiplex things on the controller but still doable (since others have done it)

[chrisalbertson]

What is the status of this? Does anyone even have source code for PP? If reasonably current source exists I'll do the mechanics of getting this started.

[North Country]

What is the status of this? Does anyone even have source code for PP? If reasonably current source exists I'll do the mechanics of getting this started.

This might be a better Path Pilot Thread:
http://www.cnczone.com/forums/tormac...6-tormach.html

I gave up on Linux CNC and PathPilot. Too much trouble finding Legacy equipment and having to rely on random forum posts for tech info.

I ended up buying 2 cheap controllers from Bang Good dot com.
Also a 9 channel USB/LAN connected controller board and controller software from Planet-CNC dot com. Only $300. Looks like the controller software will do Torch Height Control now too. Planet CNC is where I am going to put my money if I am ever able to get my shop to grow.

I think the future belongs to GRBL and the Arduino. This might be a better investment of your precious time than legacy hardware. Someone who could transfer the Linux CNC algorithms to GRBL would be great.

[chrisalbertson]

I gave up on Linux CNC and PathPilot. Too much trouble finding Legacy equipment and having to rely on random forum posts for tech info.

LinuxCNC runs one new hardware too. People are running it on Raspberry Pi3 and the like. But yes it does run best on a standard tower PC box.

I think the future belongs to GRBL and the Arduino. This might be a better investment of your precious time than legacy hardware. Someone who could transfer the Linux CNC algorithms to GRBL would be great.

GRBL runs on an Arduino an performance is limited because of the very low end hardware. But I agree overall
The newer generation of Arduino-like small computers ar well suited to this task. Newer STM32 based boards are two orders of magnitude more powerful then Arduino at half the cost and this trend will continue

LunixCNC does have the advantage in flexibility. I just watched a guy bore a hexagonal hole using normal boring bar and a LinixCNC powered lathe. I'd going to try a "D" shape hole.
Skip to the very end and watch the last 20 seconds
https://youtu.be/T4q8gCpeY1A?t=1m26s