I'll just shim the Angle. Save the drilling & tapping chore. Self-levelling epoxy? Too messy for my liking.
Anyway, if you are really as precision as I imagine you are, you will still Shim the angle after the epoxy.

Depending on the amount of gap shimming would be quicker however if it was like my build, I had more than 3 mm in spots, so the drill and tap method was quicker. With a good drill bit and production gun tap the job can be completed in no time at all. If it is a hand tap, it will be longer.

It's a personal I think, cause even with 10 mm gaps shimming would still be quicker.
You just do not shim it with coca cola cans alone, but a combination of assorted washers (1 mm , 0,5, 0,25 mm thick etc.) and coca cans for example. These washers can be bought at most decent hardware stores, as they are used for shimming in all kinds of engineering. Or use different steel or brass sheet stock, or... etc etc....

Whatever floats your boat. that's why it's your MM when you have built it :D

Not here brother. Thin shim pack is 4 times the cost of a pack of screws and the 15 minutes to drill and tap was not that bad. Jacking screws are fairly typical in leveling. With some stuff in rural areas you pay astronomical prices. We always think of things as in the environment we have around us and not of the environment around that person when we offer suggestions. Something everyone is guilty of.

Amen to that Pete! Just finding what others have is a hard enough task downunder. I have just completed one rail in about 30 minutes and have two way adjustablity, needed due to the abysmal state of the PFC on my machine. We have Chinese imports to thank for that.....

I am officially rapt! Both rails done now and back on the machine. Was able to level vertically at each and every bolt location and now the Y car rides damn nice on top. About to refit the racks and take her for a spin :)

Good work, get it cutting again soon :).

I am happy to report that things are running alot better now, no strange vibrations or noises coming from the X axis now. Been doing a few halftone pictures and along with my new Amana Tools V-Groove bit the machine seems to be working great...

Awesome. Can't wait to see some pictures of items off of the machine.

Alrighty, continuing on with improvements. Something that has always bugged me was the distance Mach3 moves is not was was programmed. Say I tell the Z to move to -6mm, it will go to -5.9654. Or if I tell X to move 65mm via the MDI - G0X65- it will move to 65.213. It has been like this for ages and in some cases has stuffed up my jobs that require whole numbers versus these piece meal ones.

Firstly, are others seeing this? If not, has anyone any ideas on what I need to do to cure it.

Some info:

I am running 1:1 on my steppers. I have 30T pinions. My Leadshine drives are set to 8 microstep. That puts the Mach settings at 16.977 steps per mm.

On ebay at the moment are 25T pinions that I would consider buying or would I be better with 24T pinions. Should I advance my case for 3:1 belt drives?

I would just like to get this sorted so when I need to cut a pocket to 18mm wide and 6mm deep I actually cut those figures, especially where pieces of things need to fit together with some precision.

Any help on that would be more than greatly appreciated.


On another note I am seriously thinking of moving away from Mach3/Windows to LinuxCNC/Debian Linux. Those of you have that have done that, have you found any gotchas on the way? If I go down this path I hope to design a screenset that closely mirrors Gerries 2010 screenset that I currently use.

Again, any comments or help with that would also be appreciated.

Cheers

If you are talking about your DRO amount of movement, my programmed movement Vs. actual is within .002 when read at the DRO. As in if I do a 1.000 inch z retract, My readout will be .999 to 1.001. I have 3:1 belt drives.

Yup, it's my DRO output. For example, I am cutting out 16.5mm MDF laminate. I do that with 2 cutters, one a downcut and one an upcut. Each one was told to cut down to 8.25mm at 3mm per pass. Never really noticed the first 2 passes but the last one definitely wasn't 8.25, it was closer to 9mm on the DRO when the Gcode said 8.25. Thats what got me thinking.

I know our machines aren't accurate to .00001 but would at least think if it is told to go to 8.25 it would.

It all had to do with the calculated distance per step. A single step on the machine I made for the X axis is 0.0003" or 0.00762mm. So the movement has to be a multiple of it.

You should never see this much deviation. You resolution is about .058mm, so you can expect to be off by up to that much, but not more.

If you want better resolution, you need a gear or belt reduction.

That is something you will have to calculate out. We do not know the step angle of your steppers so we can only assume it is 1.8°. That being said, you would have finer resolution with belt reduction. I personally would stay with the 30 Tooth, it is a balancing act but the more teeth the smoother the engagement.

Don't base you decision to Linux on this. A lot of people use Mach and don't have a problem.

But your statement of

seems like there is something turned on to lower the last pass down. Ger, is there anything on your screenset that you can do this with that he may have inadvertently turned on? Are you in incremental or absolute? Do your drives have a tuning potentiometer on them and have you done that? Even the smallest mundane detail can solve a problem because it is overlooked.

No. The DRO should read exactly what the g-code tells it to read (within the step/unit tolerance).


If the G-code said Z-8.25, then, like I said before, it should be within your tolerance of .058mm.


It should. Every time. Sounds like you may have a corrupt Mach3 installation.
This isn't a Mach3 bug, something is not working right in your installation. This is not a common issue.

What version of Mach3 are you using? If you're using 3.043.066, then try going back to 3.043.062 or 3.043.057.

I know nothing about LinuxCNC, but I don't think that would be a trivial task.

There are hundreds of Mach3 screens floating around, most of them bad. :)
But there are a lot, because it's not that hard to do.

I think that there are only a handful of LinuxCNC screens. Either the ones available are really good, or it's really, really hard to create a new screen for LinuxCNC.

Thanks everyone, I'll check the mach version and change to one of those indicated by Gerry.

My change to linuxcnc would not be due to this problem , I have been thinking about it for a while now. My smoothstepper bugs me occasionally :) and I have a love/hate relationship with windowz. It would be a suck it and see process.

Gerry, just a cursory glance at at transition has been interesting. Getting linuxcnc to do something like your dual touchoff requires code to be written. I see your screenset as the best available for mach3, nothing comes close in the linux world aside maybe for gmoccapy that made an appearance a little while ago. Still nothing like 2010 though.

Bruce, this is a comment from looong ago, it may not apply these days:

We saw that Mach (and Shopbot) programming was developed for the inch users - for millimeter users it seemed to have issues.

Gerald, that is an interesting observation from long ago, I have thought of running Mach in Inch mode but then I have metric racks and pinions. If I had imperial racks etc I might be tempted to switch. I have read quite a bit on the interwebs about Mach3 having issues that should have been fixed long ago that haven't been, it wouldn't surprise me if this was one of them.

This is actually one of the reasons I wanted to try LinuxCNC, if not just to see if things improve in the accuracy.

Pete: Forgot to answer your post above. Thanks for the input re pinion size, I'll stick with 30T for belt drives for now, less expense is a good thing if nothing else :)

Cheers

That is interesting Gerald.

There is an interesting section in the mach install manual at the section of native units. For a test you could create another profile with native units as inch. I am certain you are outputting your toolpath in metric so it would take care of that part. It would be interesting to see if it is a native units issue.

Mach does have some quirks. I found that with G02/03 if you had cv stop with angles turned on and you had tabs in your tool path it would cause hesitations only seen when the feed rate was higher than 150 at the locations of the tabs. Took me forever to find the cause of the problem because it only did it when the motion was in a clockwise rotation but not counter clockwise. Turning off cv with angles got rid of the problem. Not everyone experiences these problems so it is sort of like gremlins in the machine. The thing is one you get a good running profile make sure you copy your xml file.

I am not a Mach user but in Linuxcnc you can switch between commanded and actual. Seeing the difference would drive me nuts. Prime example of driving me nuts would be this guys Dro. Cool project but is a great example of the machine not being able to always achieve the commanded position. http://youtu.be/dHXoMG2s5yE

Russell, from what I have learnt about linuxcnc to date yoy can see all sorts of things you can't see in mach. How long have you been with linux? Care to share any settings you may have that are beyond standard?

Bruce I have been using LinuxCNC for 5 or 6 years now. No special settings at all just run it like it installs. I did try to install a auto z zero but gave up. Probably the most out of normal thing I did was set the file location to load to my DropBox folder and use a old IPhone as a Pendant. I also changed the way the machine Homes itself.(first Z the X and Y at the same time)

I knew someone who had a twin set up.
He had a start up screen which asked what he wanted to run before the main start up.(was it boot up as)

Excellent, never would have picked it from your videos :) Must look at your build thread again.

One last question... did you hook up your start & pause buttons or are you running without them? Probably should look your thread to answer that :)

I hooked up the Estop but start and pause are not. Most of the time I zero with the phone and hit start from it. In a production environment where you cut the same sheet all day long and paying someone to run it I can see their worth but in this one man shop I just haven't seen the value in hooking them up yet. But everything is run just have to figure it out in the software.

Ah OK. I am going to give them a go, will share what I find out :)

I have EStop, Pause and Start on my machine and I have found them to be very useful. As Russell mentioned, it more useful when you are running the same file over and over. I also find that there are times when I need to pause a cut when I am not near the computer such as when I need to move a clamp or I have to answer my phone.

For the minor extra cost I have found them very useful already. I use them often to check for clamps, or when I forget to switch on the dust cleaner again (need to automate that bloody thing) or answering a call, also I stop the machine sometimes temporary to check after first part is cut to check the quality etc. It's a convenience not a necessity.. but damn useful.

...completely worth the time and $ to add.

Dunno if you guys are referring to me or Russell... I have them on my machine, its just working out how to get them to work under LinuxCNC :)

Russell

If you are reading this would there be any chance of you attaching your stepconf, ini and hal files from LinuxCNC? I have Y and Z performing way better than I ever had them under Mach3 but the dual X motors are driving me nuts. I just cannot get them to play together and seeing as you have been running for 5 years, yours must be doing something mine isn't

Will understand if you can't/don't want to :)

This also applies to anyone else who is running LinuxCNC successfully, any and all help would be more than extremely helpful and grateful

Cheers
Bruce

Bruce

What kind of performance changes are you seeing?

Thanks

I would but I am in a middle of a move back to Florida. When I used the setup wizard I did 2 outputs as the X axis and just reverted the one side so it would run the opposite direction.

Thanks Russell, understand. I did what you did but minea not playing ball. I have to go back to Mach (boohoo) as I have stuff to cut and will try again later.

Nils, no accurate measurements just observations. I had the Y axis jogging at 1500ipm no probs at all, smooth as silk. Under mach the best I could manage was a tad over 750ipm. It just seems so much smoother under linuxcnc.

Cheers

Well, after giving up but trying one more time I managed to get the X working under LinuxCNC. Had to do it differently than Russell but it works... or seems to. Will tweak a little more, air cut a couple of file and then look into Z touch off and Modbus for my spindle.....

Keep us updated on your progress. It will be interesting to see what you find as far as performance. I do not have the problems that you had on the DRO but my problems were in other areas. Would be nice to see pics of the computer config when complete also. It may help others down the road.

I will Pete, LinuxCNC has been a bit of a marathon effort to setup but I am finally getting there.

Got homing working, does this brilliantly too. I decided to check distances and set everything up to check the DRO vs actual travel. Told Y to go 50mm, DRO showed 50mm and the actual travel was spot on 50mm - totally rapt!

Air cutting a file at the moment, the commanded distances from G code are exactly what appears in the DRO's. If you remember I had trouble with Mach not doing that, well LinuxCNC does every time. Never going back now!

I am glad you are making headway. The Mach issue you were having seemed to be odd to say the least. I have often thought of trying a setup with LinuxCNC on another hard drive and giving it a test drive.

I do have to say for others that may read this thread that Mach does display the closest obtainable DRO that can be set based on your setup criteria. For instance and this is generalized, if your setup is calculated out to distance per step as 0.00762mm(0.000348") then to travel 50mm(1.9685") the steps would be either 6561 or 6562. So your DRO in Mach would read 49.9948mm (1.9683) or 50.0024mm (1.9686). This has to be because you step distance is a constant that is bound mechanically and electrically by the driver. Now how Mach determines which is closer I do not know, I would assume based on the direction traveling and commanding a stop not to overshoot but I do not know. I did not design it.

I posted this to help others understand what is happening. Now both LinuxCNC and Mach are excellent software controllers. I have read good and bad with both. I can also say there are a lot of very satisfied users of both. So the choice is left to the end user and in the end, the one that works the best for you is the one you use. You should pick the one that is more suited to the direction that you wish your build to develop and grow.