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Convert rotary table to CNC?

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  • Convert rotary table to CNC?

    Well here's the deal, I'm getting ready to convert my Boss 5 over to mach 3 this winter and I want to make wheels for my car but they are bigger than my mills envelop (12"x18") and easy way to solve that problem would be to mount the blank on a rotary table and mill them in "fifths". However will all the operations and tool changes it would be easier if the table was CNC controlled. Since I bought the CNC I haven't used my 10" rotary table at all since its much simple to just program an arc or cirle or bolt pattern on the CNC. The question is with a suitable motor mount could a manual rotary table function well with a stepper? I'd only use it for indexing so I'd probably use a smaller motor. Will it work or will backlash drive me crazy? Anyone suppose it's possible make an encoder to tell the control where the table is in degrees so backlash isn't and issue?

    I'm not making the whole rim, just the center of 3 piece rims and the OD and center hole as well as roughing in will be done on my large lathe. Overall diameter is 17" and most likely 7075 alloy.

    -Christian D. Sokolowski

  • #2
    Well sure,I have seen several conversions.You could even use a timing belt to play with the ratio if you wanted.

    If I'm reading you right,you want to mount the blank on the table,lock the table,let the mill do it's thing to 1/5 of the pie and then unlock and repeat on the other 4/5ths right?

    [This message has been edited by wierdscience (edited 01-04-2006).]
    I just need one more tool,just one!


    • #3
      Well lock in the sense that the stepper would hold the table in position for an op then rotate to the next 1/5 and do ops there and so on. Like holding the Z in one position while facing a part. My concern is actually holding the part as well as rotating precisely to each slice of the part. I expect several tool changes will be necessary for each part of the pie and would hope to do all 5 parts with one tool then move to the next tool and so on. I see CNC tables on ebay fetch a pretty penny, do they have something akin to a ballscrew to prevent backlash?

      -Christian D. Sokolowski


      • #4
        Have a look at the files in

        Ignore the first two. The .txt file tells you what is going on.
        The table is driven by a stepper motor & timing belt. The reduction I chose was influenced by the fact I knew I was going to be putting a big load on the table.
        The table has been very handy since for smaller jobs, & I've fitted a 10" 3-jaw chuck to it.

        I don't claim any originality, but it shows what can be done.



        • #5

          No, it's called backlash compensation. Use a dial indicator to determine it till it hits zero.

          I had my rotary cnc'ed with a stepper. Then I got mad At Mariss and pulled apart a perfectly good system and put the handle back on it.

          I have had a servo motor/drive bought for six months and laying here on the bench.

          It can have 1/2" play, as long as it is consistient. Your beds and ways need the numbers put in Mach3 too.

          And, just where to put the wear compensation into Boss software?

          BY the way, I downloaded 4.2 sherline EMC (free), burned it and it works fine, installs, looks good. OF course Mastercam and other programs are not available, thou it could be networks. It grabs the numbers out of the router, modem and hooks to the internet in seconds. Nice looking Linux.
          Excuse me, I farted.


          • #6
            Ohh, and I made a big cross, with aluminum stand offs and clamps milled right into the top.

            I put a Morse spindle nose on the middle, welded it in. It drops into the morse taper in the center of the indexer, bolted it to the indexer t-slots, then turned on the mill, turned on the table and let it cut the shoulder for the wheel to sit in. It made it'self centered, and accurrate as long as the wheel is round.. that is.. I was carving cast fatboy Harley wheels here. I sold three.. I have three left.. I think.. The gecko drives died in the middle of one job and I gave that wheel away. Losing the drives, losing a wheel, I have not done anymore. (done kicked my butt, I'll be ready and confident next time)
            Larken drives have been reliable and I should get back onto that project.

            Re: (after breakfast).. yeah I'm a lazy bastich..

            OKAY, now for reality.. IF you put Mach3 on your computer, If you want it to be reliable and actually perform work. You must disable about 3/4 of the background activities it does. Nobody told me this when I started. I crashed a few end mills. The cutter speed would bobble, I'd look up and see a balloon telling me to stay connected for updates from Microsoft. As the cutter speed would bobble, sometimes.. it'd snap. Ain't nothing like losing a endmill to piss off a poor man. When you "GUT" xp's background you also do away with running Cad programs (sometimes) and other functions.

            I posted a setup list of things to do to make XP damn near single tasking and wonderful.

            EMC, it is very hard to set up. The Rtlinux kernel is the worst thing I have tried to deal with with my DOS and programming background. When the newer Live BDI's came out they ran from cdrom, unfortunatly, making the configuration to "your" machine's io and tuning setup is not on the cd.. so .. you have to install it to access that..

            IF you plan on making money with your machine, DO not depend on just one system. If you use DOs, you can use turbocnc too. It can boot off a floppy, but.. Dos does not recognize more than one parallel port, so keep it simple and keep it working.. Mach3 will run fine on one port. EMC, should give you another option, it is much better timing wise than turbocnc. Not as simple, but better.

            Mach3 is king around here. The Wizards on top of the screen do about 90 percent of what I need. My machine will run on turbocnc too.

            Turbocnc can run with Freedos, they even have USB support now.

            Hey, Ain't I tried to help you enough? Sounds like you are buying dinner next trip through.

            NEIL: It'd be nice to see the above in print with your cnc series, perhaps the XP setup available from Art at He emailed it to me, it is about a page long. HIS documentation is better on Mach3 than anything I have ever saw. Much due to the fact the world assists him making a better software. *yahoo.. you can talk to the author.

            [This message has been edited by David E Cofer (edited 01-04-2006).]
            Excuse me, I farted.


            • #7
              Thanks guys. If the table has backlash and you use backlash compensation to properly position how do you keep the table from moving when milling? I suppose I could use the table locks but that sort of defeats the purpose of CNC unless I controlled them from software somehow.

              Dave, I got a little one and a wife that drives me nuts but if I ever get down your way I'll gladly buy the dinner. Best restaurant in town even!

              -Christian D. Sokolowski


              • #8
                Most all the tables have "backlash nuts" with springs or washers in them.

                My rotary indexer small amount of backlash has not shown in anything I cut, and I engraved the wheels with letters (deskengrave) "is free" to write the gcode for any windows font.

                Yeah, I had a machine I had built, the old drill press cnc w/cross slide. It'd bounce around the end play. It was too light.

                If that rotary has that much slop, take it apart and shim it. Probably you will find that it has a adjustment nut on one end. IF the gears are "that" worn, nothing will help. Perhaps some heavy grease? that takes up slack too.

                I got a 4" indexer I cut balls on the lathe with (has a toolpost on it).. it chattered once or twice, but I moved the tool lower and it was better.
                Excuse me, I farted.


                • #9
                  JohnS: said EMC is a black hole for wasted time, probably wrote by communist who wanted to destroy production in America..(ha ha)..
                  In a lot of ways, he is right. I have spent about a hundred hours trying to get it to work. It requires certain video cards and cpu's.. So does XP thou.

                  Mach3 Configuration.. save this..

                  ** First check your system Bios for a setting called
                  "Advanced C1E Enable" in CPU BIOS settings and disable it.

                  0. Install Windows in Standard PC Mode

                  1. When you see the installation tell you to press F6 (Third Party
                  SCSI or RAID Drivers) press F5 instead.
                  2. You will see Press F2 for Automated System Recovery, (DONT press
                  3. Right after that you will see a list.
                  4. Press the UP arrow key to highlight Standard PC.

                  When installing, make SURE you install all of the most recent drivers
                  for your
                  Hardware. This is vital!

                  1. Disable Visual Effects

                  1. Right-click on your desktop, and then click Properties.
                  2. Click the Appearance tab.
                  3. On the Windows and Buttons menu, select Windows Classic.
                  4. Press Effect button.
                  5. Deselect all options (maybe leave ClearType on)
                  6. Hit OK

                  2. Set Processor Scheduling for Background Services

                  1. Right Click My Computer and select Properties
                  2. Click Advanced tab.
                  3. For "Processor Scheduling" set for Background Services
                  4. Click OK.

                  3. Optimize Virtual Memory Swap File

                  1. Right Click My Computer and select Properties
                  2. Click Advanced tab.
                  3. Press Change for Memory Useage / Virtual Memory
                  4. Depending on how much RAM you actually have is what you are going
                  to enter here: If you have 256MB RAM set this to 512 for Min and Max
                  If you have 512MB RAM set this to 768 for Min and Max If you have
                  1024MB RAM set this to 1536 for Min and Max
                  5. Once entered hit SET
                  6. Hit OK
                  7. and then Hit OK Again.

                  4. Disable System Restore

                  1. Right Click My Computer and select Properties
                  2. Click System Restore tab.
                  3. Click "Turn off System Restore on all Drives"
                  4. Click OK.

                  5. Disable Error Reporting

                  1. Right Click My Computer and select Properties
                  2. Click Advanced tab.
                  3. Click Error Reporting button at bottom.
                  4. Click "Disable Error Reporting"
                  5. Click OK.

                  6. Disable Automatic Updates

                  1. Right Click My Computer and select Properties
                  2. Click Automatic Updates tab.
                  3. Uncheck Keep my computer updated..
                  4. Click OK.

                  7. Disable Remote Assistance

                  1. Right Click My Computer and select Properties
                  2. Click Remote tab.
                  3. Uncheck "Allow Remote Assistance Invitations.".
                  4. Click OK.

                  8. Disable Remote Desktop

                  1. Right Click My Computer and select Properties
                  2. Click Remote tab.
                  3. Uncheck "Allow users to connect remotely to this computer"
                  4. Click OK.

                  9. Set Computer to Standard PC NOT ACPI PC
                  NOTE: This is only necessary if you wish to remove ACPI AFTER install.
                  If you followed step 0, you don't need to do this.

                  1. Right Click My Computer and select Properties
                  2. Click Hardware tab.
                  3. Click Device Manager Button in the middle.
                  4. Double click "Computer".
                  5. Right click on Standard ACPI PC and choose Update Driver.
                  6. Choose "Install the software from a Specific Location (Advanced)"
                  7. Click Next.
                  8. Choose "Don't search. I will choose driver to install."
                  9. Click Next.
                  10. Choose "Standard PC" from the listing.
                  11. Click Next.
                  12. Click OK.

                  10. Enable DMA on all Disk Controllers

                  1. Right Click My Computer and select Properties
                  2. Click Hardware tab.
                  3. Click Device Manager Button in the middle.
                  4. Double click "IDE ATA/ATAPI Controllers"
                  5. Right click on Primary IDE Channel and choose Properties.
                  6. Click Advanced Settings tab.
                  7. Choose for Transfer Mode: DMA if Available.
                  8. Click OK.
                  9. Right click on Secondary IDE Channel and choose Properties.
                  10. Click Advanced Settings tab.
                  11. Choose for Transfer Mode: DMA if Available.
                  12. Click OK.

                  11. Disable Startup Items in Registry

                  1. Click Start button.
                  2. Click Run.
                  3. Type MSCONFIG and press [ENTER].
                  4. Click Startup tab.
                  5. Uncheck anything you think you don't need.
                  6. Click OK.
                  7. Exit MSCONFIG.

                  12. Disable Startup Program Group Items in Start Menu

                  1. Right click Start button and choose Open.
                  2. Double click Programs.
                  3. Double click Startup.
                  4. Delete anything you think you don't need.
                  5. Close window.

                  13. Optimize System Services

                  1. Click Start Button.
                  2. Click Run.
                  3. Type SERVICES.MSC and press [ENTER].
                  4. Set your services to these:

                  Alerter Automatic

                  DHCP Client Automatic

                  DNS Client Automatic

                  Event Log Automatic

                  IMAPI CD-Burning Automatic

                  ICF/ICS Automatic

                  Logical Disk Manager Automatic

                  Plug and Play Automatic

                  Print Spooler Automatic

                  Remote Access Auto Connection Manager Automatic

                  Remote Procedure Call Automatic

                  Routing and Remote Access Automatic

                  Secondary Logon Automatic

                  Security Accounts Manager Automatic

                  Server Automatic

                  Shell Hardware Detection Automatic

                  System Event Notification Automatic

                  TCP/IP NetBIOS Helper Automatic

                  Telephony Automatic

                  Upload Manager Automatic

                  Windows Audio Automatic

                  Windows Image Acquisition Automatic

                  Windows Management Instrumentation Automatic

                  Windows Time Automatic

                  Wireless Zero Configuration Automatic

                  Workstation Automatic

                  Human Interface Device Access Automatic

                  Application Layer Gateway Service Manual

                  COM+ Event System Manual

                  Cryptographic Services Manual

                  Network Connections Manual

                  Remote Access Connection Manager Manual

                  SSDP Discovery Service Manual

                  Universal Plug and Play Device Host Manual

                  ALL OTHERS Disabled

                  5. Click OK.

                  14. Optimize in Registry

                  1. Click Start button.
                  2. Click Run.
                  3. Type NOTEPAD and press [ENTER].
                  4. Copy the below lines to the clipboard.

                  Windows Registry Editor Version 5.00

                  [HKEY_LOCAL_MACHINE\System\CurrentControLSet\Contro l\Class\{4D36E96A-


                  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Filesystem]


                  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentContolSet\Control \Filesystem]


                  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\FileSystem]


                  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Explorer


                  [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Contro l\PriorityControl]


                  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\FileSystem\CDFS]




                  5. Paste into notepad.
                  6. Save file as Optimize Registry Settings.reg
                  7. Close notepad.
                  8. Double click Optimize Registry Settings.reg
                  9. Answer Yes/Ok when prompted to merge registry.

                  15. Add below to SYSTEM.INI:

                  1. Click the Start Button.
                  2. Click Run.
                  3. Type SYSTEM.INI and press [ENTER].
                  4. Find the section with [386 enh] and add this:

                  [386 enh]

                  5. Add this section at the top under [386 enh]


                  16. Set Windows Theme to CLASSIC

                  1. Right-click on your desktop, and then click Properties.
                  2. Click on Themes tab
                  3. Set Themes to Windows Classic
                  4. Hit OK

                  17. Disable Indexing on all NTFS drives

                  1. Double click My Computer.
                  2. Right click on hard drive and choose Properties.
                  3. On bottom, uncheck "Allow Indexing Service to index this file for
                  faster searching". 4. Hit OK.

                  18. Run diskperf -n

                  1. Click the Start Button.
                  2. Click Run.
                  3. Type DISKPERF -N and press [ENTER].

                  19. Disable Autoplay on all CD-ROM Drives

                  1. Double click My Computer.
                  2. Right click CD-ROM drive and choose Properties.
                  3. Click AutoPlay tab.
                  4. For rest of steps you need to go through each one of the types:
                  Music Files, Pictures, Video Files, Mixed Content, Music CD, and Blank
                  CD these steps:

                  A. Choose Select an action to perform (at top).
                  B. Choose "Take no action from list"".

                  5. Click OK.

                  20. Disable MSN Messenger

                  1. Double click on the Messenger icon in the system tray to open it.
                  2. Skip thru the internet and sign up stuff, just cancel it.
                  3. When Messenger loads go to Tools -> Options then Preferences.
                  4. Uncheck 'Run this program when windows starts'

                  21. Disable Power Management

                  1. Right-click on your desktop, and then click Properties.
                  2. Click on the Screen Saver tab.
                  3. Set Screensaver to None.
                  4. Press the Power button near the bottom.
                  5. Set all options to NEVER shut down automatically!

                  22. Disable Wallpaper

                  1. Right-click on your desktop, and then click Properties.
                  2. Click on the Desktop tab.
                  3. Where it says Background, scroll all the way up and choose None.
                  4. Click OK.

                  23. Disable System Sounds

                  1. Click Start Button.
                  2. Click Settings.
                  3. Click Control Panel
                  4. Double click Sounds and Audio Devices.
                  5. Click Sounds tab.
                  6. For Sound Scheme, choose "No Sounds".
                  7. Click OK.

                  24. Update Windows

                  1. Double click on Internet Explorer from desktop.
                  2. Select Tools from menu then Windows Update.
                  3. Follow instructions.
                  4. If update tells you to reboot, do so!

                  25. Install Programs

                  Do not install any programs you will not use. Only install programs
                  that you DEPEND on for what you do on your computer. Keeping things
                  lean and mean will keep your system fast and stable.

                  26. Maintain Hard disk

                  1. Double click on My Computer.
                  2. Right click on Hard Disk and choose Properties.
                  3. Click Tools tab.
                  4. For Error Checking click Check Now. Do before Defrag!
                  5. Click Defragment Now, AFTER Error Checking completes.
                  6. Click OK.

                  [This message has been edited by David E Cofer (edited 01-04-2006).]
                  Excuse me, I farted.


                  • #10
                    I wonder if "XP Embedded" would be a better choice over XP Professional. Could a home user purchase the OS?

                    [This message has been edited by JPR (edited 01-04-2006).]


                    • #11
                      For this mode of operation, I would definitely consider a locking mechanism for the table. I use my table manually and always lock it down before milling or drilling. This makes sense for two reasons. First, there is backlash and the forces involved with a milling cutter in cutting out an irregular shaped hole will vary over all 360 degrees in the horizontal plane so the work will rotate back and forth during the operation.

                      Second, there is the table itself. If the worm and worm wheel are absorbing all the forces of the milling operation, then they will be subject to excessive wear at those positions. If you are making multiple parts with this setup, the same locations on the worm gear will get the bulk of this wear. This will cause them to become inaccurate. Personally, I wouldn't want to do this to my rotary table.

                      I would consider either motor or solenoid operated clamps for locking it in position.

                      Paul A.

                      Paul A.
                      SE Texas

                      Make it fit.
                      You can't win and there IS a penalty for trying!


                      • #12
                        Hmm, Paul...

                        I don't want to argue, just interject...

                        Don't we do that with our cnc' tables anyway? A rotary indexer is much cheaper than table screws.. *machining the same place.. wearing out the same threads.

                        My indexer cost me $200 used.. New it is over 2k.. but I'd rather crap it out than the table screws. Just putting that heavy rascal on the table pisses me off and the table tuning. I had to slow it down to 80ipm.

                        Locking something down helps. Using it wears it out. Hopefully a lifetime of use.
                        Excuse me, I farted.


                        • #13

                          I was told by a reliable source, windows 2000 has the same kernel and less overhead, less cost, less problems.

                          Mach3 states XP.. I bought XP.. I don't know about 2000 myself.

                          As we all know, I am not perfect, nor a super genuis. I am learning too. Daily.

                          I can tell you the new Sherline 4.2 EMC looks better than anything else I have seen come down the pipe. It installed as easy as windows, ran right off.. the Penguin looking up at a butterfly with a fly swatter in hand.. I laughed.. and called the wife to look too. By the way, the OS and the program is free to download and burn onto (1) cd. It does require a new computer, not some old wore out 486..
                          Excuse me, I farted.


                          • #14

                            Always two ways to look at any subject. Many times more than that. That's why we're here.

                            Paul A.
                            Paul A.
                            SE Texas

                            Make it fit.
                            You can't win and there IS a penalty for trying!


                            • #15
                              I HATE XP, been using win2k since theday it came out. Prefer SCSI drives for critical machines as they have less CPU overhead. Win2k can be stripped to the bone and run lean and mean, used to do it all the time when I was into gaming. It'd be really cool if there was a dual CPU version of Mach 3. my web browsing comp is a dual P3 Xeon 550 box with 2 gigs ram got the parts on ebay cheap. Quiet, stable and in many ways faster than the sum of the two processors. Got the really fast machine in the basement, video editing and the like. Athlon XP64 CPU, 4 gigs ram, 15K rpm SCSI boot and programs drive with two large SATA drives for editing. Stripped everything I don't need and use Winlauncher to run the editing software at high priority, framerates and quality are better than my digicam is capable of. Rips DVD's like lightnin'

                              I was looking at the rotary table today. I think I can rather easily hook up some large air cylinders I have lying around to the camlocks and use an M-code and opto relay to control them then backlash comp for the stepper. It's a cheapy import that got used for one job before I bought the CNC so virutally zero wear. Guess I'll have to get moving on that upgrade....

                              -Christian D. Sokolowski