sherline, cnc, and masso

[Hugh Currin]

Zee:

It shouldn't matter if the lead screw pitch is inch or metric. A constant in the software can convert either to metric or inch. Could even set up two configurations (in LinuxCNC at least) one for each unit system. This shouldn't be a consideration. But the cost of a ball screw machine from Sherline is a consideration. They are expensive.

I haven't gotten around to installing limit or home switches on my knee mill or my Sherline system. That's 15-20 years for the knee mill so it seems I haven't missed them a lot. The envelope limits are pushed more often with the Sherline but still haven't felt the need. With the Sherline I set machine zero near one end at extreme travel positions. From there I depend on software limits which seem to be reliable. I just command the machine to it's machine zero position before shutting it down. Then on start up I make this position again machine zero. I don't depend on this position for tool offsets, I set them for each session, but for limits it's more than adequate. I think this is what kvom is doing also.

It seems everyone who hasn't used a CNC machine wants to have manual control. But once you use one for awhile it becomes a non-issue. I only use the hand wheels (power off) to re-set my machine zero when everything is way out of whack. Doesn't happen often. But when running why would you want to use the hand wheels? I think all reasonable controllers have robust jog and MDI buttons. LinuxCNC at least has a smooth jog (push button and axis moves smoothly at give speed till you let up on the button), and incremental jog (set a step size and each button push moves that far, say 0.0005" or 1.000"). I find this more user friendly than a hand wheel. Also, using the jog buttons you get a great DRO. The CNC display keeps up with moves showing a display of position. What more do you want? [OK, you quickly learn to check the increment so you don't push the button to get 0.001" but really get 1.000". A learning process.] And MDI executes G-code commands one at a time as you type them in. Want to move to X=1.265", type G1 X1.265 F? and press the button (F? is speed to use). Only limited by your memory of G-codes (mine is very limited). Very minimal need for manual positioning, don't worry about this.

If a controller doesn't have these features I'd look for another controller. I know LinuxCNC does.

I haven't used a pendant. This may be even more convenient than the keyboard.

You will need an encoder, speed sensor, on the lathe. This is needed for threading.

What an exciting adventure. With your background in computers it shouldn't be too difficult. And there are lots of folks here, and other forums, to help. These guys sound like they know what they're talking about. I'm fairly incompetent but I'd listen to everyone else. :-)

Have fun.

[zeeprogrammer]

Thanks all.

Yeah I should have realized manual control with CNC isn't needed. I suspect industrial grade CNC machines don't even allow it.
Yep. Can do without limit switches but seems pretty handy.
Good info Alex. We may be talking more.
Ball screws are indeed pretty pricey. I'll probably avoid that, at least for now.

I'm hoping to use a laptop for my computer.
So far I'm thinking I need to look into...

a) driver box for the steppers
b) some kind of box to interface the driver box to the computer (i.e. I think, USB to parallel something)
c) software to output g-code (LinuxCNC seems the way to go)
d) software to generate g-code (CamBam?) I know I can write my own and probably will for a while)

What I fear most is getting/buying a bunch of stuff only to find out there's a feature missing.
At the same time, I have little knowledge so it's easy not to know what I even need/desire.

An example...I was looking into this a few years ago and at that time I couldn't find software to support a lathe. That turned me off. Now it appears there's more support.

[kuhncw]

Hi Zee,

Quoted: "Thanks Chuck. I've heard good things about Taig but I like the flexibility and accessory list from Sherline. Also, it doesn't look like Taig offers a CNC lathe."

Taig has had a CNC lathe on the market for a year or more.  Its an interesting design, somewhat based on their mill.  Google the  TAIGTurn 3019CR

Regards,

Chuck

[zeeprogrammer]

Thanks Chuck. That particular model appears to be CNC-ready. Not full CNC.
Taig's website leaves something to be desired. A full CNC lathe was actually CNC ready. Two others differ by $100 but it's not easy to find out the difference (and I didn't look).
Still, I intend to explore Taig a bit more...at least to learn what, if anything, sets them apart.

[Alex]

Zee;

My approach with the lathe is that ball screws are not a necessity. Reason: you are (usually!) each axis is usually pushing or pulling for the cut. Mills can change direction during a cut.

Saying that, LinuxCNC (and, probably all others) allow one to specify the backlash, so that when direction of an axis is changed, it gives a quick extra bit of a turn equivalent to the backlash.

I use CamBam, from DXF files. The lathe support (last time I looked) was not fantastic, but was ok.

Conversational programming is a good way to go. LinuxCNC has "Features" I think it's called. You create machining with a click of a mouse (or, push, if a touch screen)

I'd probably not bother with a manual mill. I do have an old one, though.

Guys I worked with for a couple of decades were great. Whenever I needed machining (for work) I'd go and get a work order. These guys convinced me that a manual mill was from the stone age; and with conversational programming, they were right. They ONLY did one-offs or very small production runs. More than about 10 parts, they'd send it out to a commercial shop.

Zee - this is ALL fun stuff; lots to learn, and that keeps the olde brain going.

[Admiral_dk]

b) some kind of box to interface the driver box to the computer (i.e. I think, USB to parallel something)

WARNING almost all manufactures off Software and a good numbers of those making Hardware controllers warns that USB-2-Parallel Port Converters DO NOT work as they should in this application !!!!

[zeeprogrammer]

Thanks Alex. You've given me some more good information.

WARNING almost all manufactures off Software and a good numbers of those making Hardware controllers warns that USB-2-Parallel Port Converters DO NOT work as they should in this application !!!!

Your post was timely. I've been looking at such things. Does the same hold true for the ethernet version of smoothstepper?

One of the things that was pushing me to go for the Sherline CNC-ready is that it comes with a CNC rotary table. But Sherline says I can buy the manual workshop and upgrade the manual rotary table.
So as of 4:36 PM ET, my thinking is to buy the manual system with upgraded rotary table, learn the machines, and later get the stuff to modify to CNC. The cost difference between CNC-ready and manual with conversion kits isn't enough to stop me.

We'll see how things are at 4:37.

[Mike R]

Your post was timely. I've been looking at such things. Does the same hold true for the ethernet version of smoothstepper?

My understanding of the ethernet (and some USB connected cards) is that the critical timing is handled on the card, and this is why they can work.  I.e. the software sends a message like move 512 steps on X and the card then handles the timing of generating the 512 pulses necessary.  It takes very little time to send the message relative to the actual motion so it all works ok.  The USB to parallel adapters don't work because the software is trying to do the timing precisely for each individual step of the 512 and the USB port doesn't necessarily always do as its told exactly when its told...it can put it off just a bit which throws the timing out the window, and then you throw your part out the same window...


As for software and the PC, I've found that a dedicated PC setup for the cnc machine suits me best.  You can run Linux on relatively old machines when using one of the Mesa ethernet cards, and again my experience is that once the operating system is installed, its less about the operating system and more about the specific control software that you end up diving into to do the editing of things.  Examples would be creating your own displays, adding on other peoples creations (youch probe screens and tool setters, other canned cycles / conversational add ins),  and generally getting the control software to do what you want - i.e. move the machine, turn on the spindle, spin the rotary table (and the right way!), switching on things like coolant (maybe not on a Sherline or Taig).  The list goes on, or it can be very short. AS previously mentioned, there are many people willing to help with either flavor of system chosen (Windows or Linux).


I've probably spent more time setting up and converting my cnc machines than using them but its been fun and I hope to use them more in the future.  Enjoy the journey.  All time in the shop is time well spent.


Mike

[Admiral_dk]

I see that Mike R has already answered your question.

ALL the critical timing is done onboard (inside) on the modern serious controller and that is the reason it's not critical what OS that runs the computer, nor the interface type. There is very much a limit to how accurate (especially) Windows can control the Parallel Port + the cable and the Opto-Insulators (that hopefully is inside the controller board) is also a limit. All this give a very finit resolution / speed limit - not nessesary a big deal on amatur basis - but considered useles in the Pro World.

This is also why all the Pro models runs on Ethernet as it is gavalnicly insulated between all units in the chain => a burned PC will NOT destroy the sometimes very expensive CNC equipment ....

[zeeprogrammer]

Critical timing moved to the (ethernet based) card was my understanding which was why I was somewhat surprised that USB may be a problem.

Next post will be long. It lists the various components I think I need and some notes about each.

Biggest issue for me appears to be whether I go Linux (which I've never used) or stay with Windows (which I've used from its beginning).
LinuxCNC is only app that requires Linux computer. Other applications (CAD/CAM) could be run on windows machine and output transferred.

[zeeprogrammer]

Sorry for the length of this post. Below is a component list for putting together a lathe/mill CNC system and my choices/questions for each.

‘Component’ List:

Machines
Driver
Parallel Port Translator
Power Supply
Computer
OS
Motion Control Application
CAM Application
CAD Application

Notes:

Machines: Sherline Manual Workshop package with rotary table upgraded for CNC. This allows me to play/learn the machines while I play/learn the CNC components.

CNC Retrofit: Motor mounts, motors, lead screws. The question is whether to choose Sherline’s standard steppers or high-torque steppers (almost $50 difference a piece). Seems the standard steppers are sufficient or I can start with standard and replace those motors that need more torque. Will not get ball screws at this time (pricey!)

Driver: Gecko G540

Parallel Port Translator: Ethernet SmoothStepper. Mesa has been mentioned but what is the part number?

Power Supply: I have a 20A, 0-24V supply.

Computer: I have a spare laptop.

OS: Linux appears to be the OS of choice but I’m a Windows user. Choice depends on applications (see below).

Motion Controller: Mach3, Mach4, or LinuxCNC. I believe Mach3/4 is Windows only. True? Mach3/4 has a small cost. Mach3 is stable but appears no longer supported. Mach4 appears to be fairly new and was not built on Mach3 (i.e. very different code). Mach4 appears to be under significant development and documentation may be lacking. LinuxCNC is very popular (and free).


CAM: CamBam (Linux or Windows). The question is what else (free or cheap) is available. Must support lathe and mill. If Windows base can move output to a Linux based machine.

CAD: I have CubifyDesign and like it. Runs on Windows but output can be moved to a Linux based machine. I keep promising myself to look into Fusion360 but not happy with the cloud requirements.

My leaning:
   Gecko G540
   Ethernet SmoothStepper
   Linux OS
   LinuxCNC for motion control
   Windows CamBam for CAM on different computer
   CubifyDesign for CAD on different computer

If not happy then I can swap Linux/LinuxCNC for Windows with Mach3/4 for a little money.

One thing I just realized...The above means I have to swap the driver between the lathe and mill. I have to noddle on that.

This all sounds too easy.

Thanks for all the help!

[Flyboy Jim]

This all sounds too easy.

Hah................easy for you to say!    

I'm learning a lot here and hope you will continue to document your journey. 

Jim

[Hugh Currin]

Zee:

I'm not sure what you mean by "upgraded for CNC" and then mention "CNC Retrofit". If the intent is to use the Sherlines manually, I don't think their CNC ready machines can be used manually. At least without some hand wheel adapters.

I used SOB (some other brand) steppers and have had no problems.

I built up a 50V unregulated power supply for my G540. I don't remember the trade off for voltage and/or unregulated. Hopefully someone will let us know. But 24V seems low. You can try it and if you have problems upgrade. That's the advantage of a system you build up, you can change out parts (true also for MACH vs LinuxCNC).

I hate Windoz. Thus I have my CAD and CAM on a Linux computer, although it isn't the computer I use for LinuxCNC. If you like Windows use it for CAD and CAM as there are more choices than for Linux. I use a thumb drive to move G-code to the LinuxCNC computer (sneaker net). I use and like CAMBAM. There are additional hoops to jump through to run it on Linux, so running native on Windows would be preferred.

I'd suggest building up the electronics side for your mill. You can move it between the mill and lathe until your tired of doing this, then duplicate the system for the lathe.

It is too easy. Well, until you start doing it and run into that old bugaboo of "Details". But so far so good, enjoy the journey.

Machines: Sherline Manual Workshop package with rotary table upgraded for CNC. This allows me to play/learn the machines while I play/learn the CNC components.

CNC Retrofit: Motor mounts, motors, lead screws. The question is whether to choose Sherline’s standard steppers or high-torque steppers (almost $50 difference a piece). Seems the standard steppers are sufficient or I can start with standard and replace those motors that need more torque. Will not get ball screws at this time (pricey!)

Power Supply: I have a 20A, 0-24V supply.

CAM: CamBam (Linux or Windows). The question is what else (free or cheap) is available. Must support lathe and mill. If Windows base can move output to a Linux based machine.

One thing I just realized...The above means I have to swap the driver between the lathe and mill. I have to noddle on that.

This all sounds too easy.

[RonGinger]

I believe Mach3/4 is Windows only. True? Mach3/4 has a small cost. Mach3 is stable but appears no longer supported. Mach4 appears to be fairly new and was not built on Mach3 (i.e. very different code). Mach4 appears to be under significant development and documentation may be lacking.

You almost have this right. Mach3 has not been developed for more than 7 or 8 years now, but continues to sell because so many people know it and like it- A CD copy of it is shipped with many routers, some even have a cracked license.

Mach4 has been shipping for more than 7 or 8 years but mostly to industrial (OEM) customers. Their is a feeling that not many are using it, but thats really because the forums are not loaded with users discussion. The market has changed from the days when lots of development was happening, driven by the forums. Art Fenerty, the original writer of Mach3 ( actually first called Master5, then Mach1 and Mach2) used the web heavily for his input and direction. Art had no knowledge of CNC when he started, he was an X-ray technician doing CNC for a hobby. Brian Barker, the current owner of the Mach business, is an engineer with years of experience in CNC- he became Arts mentor, then bought the business when Art wanted to retire.

There is a lot of documentation for Mach4. Their is a folder, strangely enough called docs in the Mach4 install with it.

Mach3 and Mach4 both offer wizards, or conversational programs as add-ons. In Mach3 they are written in a Visual Basic like language, in Mach4 they are a standalone program but can transfer code into Mach4. I wrote the Mach4 wizards and still support both.

There are many motion controllers beside the SmoothStepper, but since it was the first controller offered with Mach3 it is probably the largest in use. There are good controllers from PMDX, and several others, even some high end commercial ones for over $1k. PMDX offers a complete box, with the stepper drivers and power supply and motion control in one neat package that is ideal for Sherline size machines. At Cabin Fever last week Steve Stallings of PMDX was showing a new box he is developing to replace the Sherline control.

I am obviously biased, since I work for Mach, but If you are a windows user trying to learn Linux just to run a free LinuxCNC seems like the hard way to get to a usable machine. Mach does have support, there is a good forum machsupport.com and there are people paid to follow it and answer questions. You can post a problem and expect to get help.

[zeeprogrammer]

I'm not sure what you mean by "upgraded for CNC" and then mention "CNC Retrofit". If the intent is to use the Sherlines manually, I don't think their CNC ready machines can be used manually. At least without some hand wheel adapters.

I built up a 50V unregulated power supply for my G540. I don't remember the trade off for voltage and/or unregulated. Hopefully someone will let us know. But 24V seems low.

By "CNC Retrofit" I mean getting the parts to convert the manual system to CNC. By "upgraded for CNC" I'm referring to the rotary table only. The manual rotary can't be converted to CNC so the idea is to buy the manual workshop but swap the manual RT for the CNC version.

Good point about voltage. I'll need to learn more. The Sherline steppers give voltages of 3.2 (standard) and 4.5 (high torque). I'm not sure what that means. I'm more familiar with DC motors.

Ron: Thanks for the clarification and I'll check out the PMDX.

One thing (and probably more) that I forgot is spindle speed. What did you all do about that (if anything)?