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Emco compact 5 cnc lathe with Welturn

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Chris Richards 327/11/2015 16:30:01
68 forum posts
13 photos


Just wondering if anyone has used an Emco compact 5 cnc lathe with the Welturn software?

I'm just trying to find a cad software to create the .Cnc files which contain g code. I can potentially manually write them but that's about it.



Emgee27/11/2015 17:02:56
1650 forum posts
224 photos


Don't forget the 209 line limit per program for the computer in the Emco Compact 5 CNC lathe, most programs will generate G code programs with many more lines than that for relatively simple workpieces.

Any program generated will also have to use the G & M codes recognised by the on board computer, that excludes many used in CAM programs.

Using the cycle commands available in the program produces a program with very few lines of code to produce many parts, G84 turning and boring, G88 facing & the G?? threading cycles are the most commonly used. There are others for grooving, drilling and reaming but not as much used as the others.

Did you ask the same question on the Yahoo Emco Forum ?


See the MFI Tutor on Youtube.


Edited By Emgee on 27/11/2015 17:05:51 ( Wrong link posted)

Edited By Emgee on 27/11/2015 17:13:41

John Haine27/11/2015 17:09:03
3271 forum posts
175 photos

Two options occur to me. One is to download LazyCam from the Mach 3 site (New Fangled Solutions) - this has a turn option. It's intended to work with Mach3 but just generates gcode which could be used with any machine (but might need a bit of editing). I believe LazyCam is free to download.

The other is to download the evaluationcopy of Mach 3 Turn and use its wizards. These generate gcode files that can be opened for edit from the "auto" screen, opening as text files which you can then "save as". You will not be able to use Mach 3 itself of course without a licence but you don't need to for your purpose. I am not in favour of mis-using software but this option is technically permitted by Mach3 though it has licence protection if you want to use the full package for CNC. It may also limit the length of gcode you can generate (500 lines rings a bell).

Chris Richards 327/11/2015 18:25:23
68 forum posts
13 photos

Hi Emgee, I might be wrong but I think the limit is lifted when using the Welturn software as the pc is feeding the the code to the machine, I guess the codes are still limited though.

I did ask the question on the Emco group but it doesn't seem to active. The mfi looks like an option but every time I add a line it inserts it as an empty line for some reason :-/

John, I guess that is a good work around, are parameters available that can be set to state the available g codes for the machine? It would make sense if that was a feature in the programs.

Emgee27/11/2015 21:22:45
1650 forum posts
224 photos

Hi Chris

When adding a line in MFI it inserts a G21 line, you need to highlight the 21 and enter the G code number you want, press Enter and you move into the X column, type in your dimension and press Enter, cursor moves to the Z column, type in your dimension and again press Enter. If you used G00 the cursor now goes to the Comment line, type in any note if required and again press Enter, that line is now completed and your cursor will be positioned at the next line of code.

The G code highlighted will be 00 as that was your last line G code choice, if you want another code type it in and press Enter and repeat as before.

If using a G84 you will have 6 columns for information, you need to press Enter for each of the columns to complete entering the line of code.

I have no experience using Welturn but you are probably correct regarding program length.


Chris Richards 329/11/2015 22:03:21
68 forum posts
13 photos

Emgee, thanks for that I was pressing the insert button rather than the return key, so that solved that issue

John I have tested the lazy cam theory, with that I managed to convert a dxf file in to g code. I then managed to get that into the Welturn and then face the next challenge. It wasn't quite happy with the format, I found Welturn needs the percent "%" at the start and end of the file.

I'm now at the point I think I'm out of my depth or no longer have the will to carry on

Chris Richards 329/11/2015 22:05:50
68 forum posts
13 photos

Ps open to swaps for a capstan lathe

Fatgadgi30/11/2015 18:24:14
163 forum posts
21 photos

Hi Chris

Impressed that you even showed willing to try learn how to use it ..... I don't have the skill or frustration threshold to write more than a couple of lines of G code in that manner.

I acquired a rusty 5 few weeks ago and after a (very) short deliberation decided to convert it to work with an external PC under Mach3 and try to use Fusion to do the CAM bit.

I have refurbed and slightly modified the mechanicals now, and I've made a big pile of obsolete electrical boards in exchange for some nice shiny modern electronic bits. Will finish the wiring in one / two weeks then it's ready for it's first trials.

Getting exciting now smiley

Cheers - Peter

Chris Richards 330/11/2015 22:20:57
68 forum posts
13 photos

Hi Peter,

You need to keep me posted on your conversion. I want to know if it's any easier to operate and importantly how much it costs to convert. I purchased the lathe to try learn cnc as I'd like to get larger machines in the future but not sure if it's for me at the moment :-/

Fatgadgi01/12/2015 11:03:20
163 forum posts
21 photos

Hi Chris, will do

The costs so far, not including any replacement mechanical refurbishment bits & pieces (bearings etc).

£94 for two new steppers and drivers.

£14 for a breakout board.

3 limit / homing sensors already had, but say £4 each from China (but microswitches are much cheaper )

Old PC and monitor was free from the loft

Mach3 Demo version is free (but I will upgrade when all works)

Fusion 360 free (for us)

Plus few quid for new connectors etc.

I am re-using the original power supply and motor speed control, but have made a new shaft encoder disc to match Mach3's maximum resolution. Emgee was kind enough to advise how to control the original motor board from Mach3, which I will do but at a later date.

Of course it may all go wrong ......... in which case I will go quiet for a long time blush

mike T01/12/2015 12:22:05
173 forum posts
1 photos

Quote. "Emgee was kind enough to advise how to control the original motor board from Mach3"

I have an Emco 5 CNC and also an Emco F1 CNC mill. Both are controlled by an external PC. I would like to learn how to control the original Emco motor control board from an external PC.

Does it control the motor speed like the manual knob, or does it just switch the motor on and off? Either function would be very useful.



Emgee01/12/2015 13:00:43
1650 forum posts
224 photos

mike T

Which control program do you use for both machines?

Is the lathe the Compact 5 cnc (has the larger control box with integral computer) or the 5PC that needs an external computer ?


John Stevenson01/12/2015 13:14:12
5068 forum posts
3 photos

I did an F1 last year, could not make heads or tails over the motor speed board other than it was all at mains voltage so just returned the whole remote box to the customer and fitted 3 M542 drivers, 3 new steppers [ old ones were crawling ] and a KB speed board. This way I got everything under Mach3 control including starting the spindle and the speed.

Fatgadgi01/12/2015 13:56:32
163 forum posts
21 photos

Hi Mike

If I have understood the principle (feel free to jump in Emgee if I have not grasped this correctly), the speed control potentiometer varies the voltage to the (probably) wiper terminal (other configurations are available !!!!) that is basically a ratio of the maximum voltage across the other legs.

So in principle, what is needed is to apply a voltage to the terminals that received the variable voltage and the motor speed should vary as a ratio of that voltage. And a standard way of outputting speed control signal is to use 0 to 10v.

Apparently there are boards available (eg Hoffmann) that can provide the interface. I have not gone into any detail or measured anything yet, but I'm thinking if that is the correct principle, then I may be lucky - it might be possible to use the breakout board output, which is isolated, almost directly.

I will need to ask for a bit of help when I get that far, but I can see there is a possibility.

The on / off control, on the other hand is more straightforward as I will use the outputs on the breakout board to switch a relay in the same way that the original switch did and probably use that switch to provide an override.

sam sokolik01/12/2015 14:19:02
60 forum posts

We had gotten a bunch of emco 'PC' machines. I had found an artical on hacking the interface board to work with mach. (getting rid of the octal latch) I was able to generate the required latch signal within linuxcnc hardware abstraction layer. (hal)

Instead of reposting all the stuff here - I did a little write up on hsm.


sam sokolik01/12/2015 14:21:40
60 forum posts


mike T01/12/2015 14:23:58
173 forum posts
1 photos

Emgee The lathe is a Compact 5 CNC with integral computer. However I have by passed the onbord computer on both machines and have a 25 pin (Mach 3 compatible) parallel port connection to my external PC. I currently use the DeskNC control program and now starting with LinuxCNC, which looks good.

John, This sounds like the way to go!!!!! Can you recall which of the KB motor speed boards you used. Can I assume you continued to use the existing Emco spindle motor?

Will, Thanks for the insight into the theory. On/ off motor control via the parallel port sounds straightforward but how do you do the variable voltage to vary the speed?

Thanks to you all

Mike T

mike T01/12/2015 14:30:16
173 forum posts
1 photos

Sam, Your reply came in while I was answering the other posts. Thanks for you input, I will need study it carefully.

An hour ago, I only had manual control of the spindle, now thanks to you guys, I have several options available.

Good stuff on this forum

Mike T

Adrian Johnstone01/12/2015 14:44:14
21 forum posts

I have two Compact 5 CNC machines that I am reworking to use modern steppers. I wanted to also redo the spindle motor because I would prefer to get rid of the large mains-voltage speed control board. Although so far all I have done is buy components, my intention is to replace the motor with a brushless outrunner, the kind designed for RC helicopters. These run relatively slowly compared to usual brushless motors, use low voltage (24V in my case) and when used with a helicopter style electronic speed controller, can be controlled by the standard RC PWM scheme and so are very amenable to CNC speed control. The downside is that they need a _lot_ of current, but for the kind of power we need an eBay standard 24V switch mode PSU will do the job.

After I started the project I found a blog that details a very similar conversion for a Chinese minilathe -

I have no idea whether this solution will deliver enough torque at low revs, and I may end up adding another pulley stage so as to allow the motor to run faster for a given spindle speed. There's no shortage of potential power, but whether it is usable at the low end is yet to be established.

Adrian Johnstone

Emgee01/12/2015 15:03:50
1650 forum posts
224 photos

Hi Sam

Very impressive conversion with a lot less work and cost associated with new steppers, drivers and related parts. like the tapered threads.

Do you know if the system could connect into the stepper boards and operate the F1 mill and the Compact 5 cnc machines ?


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