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  1. #1
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    Convert lathe to CNC

    I am new here and know very little about CNC. I would like to convert my Montgomery Ward 74LTC-2130 to CNC with a turret. I would also like to be able to convert it back to manual in the future if possible.
    Here is a picture of what the lathe looks like(not mine but same)


    If anyone has done this or has built something similar, information or links would be great.

    I know that I must do much more research on CNC. If anyone has links to help with the CNC learning curve it would be very helpful

    Thanks for your time
    Lewis

  2. #2
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    I started my research about CNC lathes.
    For software I found that a lot of people like mach3. I downloaded the demo and played with it a little. I still need to learn to use it.

    For the turret I am looking to go with this one because plans are available. [ame=http://www.youtube.com/watch?v=hdngeM662PE]CNC Lathe Tool Turret 8 Position - YouTube[/ame] I also found this one which also looks nice but no plans. Making a pulley on a Harding CHNC conversion - YouTube

    I did not find any conversions done to a Logan 10x24 or kits. I did find a couple of videos of conversions on similar lathes.
    [ame=http://www.youtube.com/watch?v=xQPiDeDypfM&feature=channel&list=UL]CNC Lathe Conversion,Clarke - YouTube[/ame]
    From what I can tell in the video he powers the head stock with the stock motor. The lead screw and the cross feed are powered with a servo motors.
    In this video at 3:00 he talks about having backlash where the pulley connects to the lead screw and that he could not thread because of it. I would like to build this lathe with the abilitly to thread just in case I ever need to. Does anyone have a solution to this problem?

  3. #3
    Community Moderator Al_The_Man's Avatar
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    They look like steppers to me?
    It appears he is using the existing lead screws, which would explain the backlash in part, otherwise with a Ball Screw set up in a thrust bearing, there should be no backlash in the pulley to ballscrew mounting?
    Also if you CNC with a ballscrew, you can get rid of the compound rest, and this generally allows a larger QCTP to be fitted, than normally would be the case if the comp. rest was retained.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  4. #4
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    LGentry, the turret is native to the CHNC. There is a brief step-by-step photo teardown of a CHNC turret here and a much more extensive description here on the Zone of the overhaul and CNC control conversion of the CHNC lathe in the video you showed.

    Randy

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    The lead screw has 0.020 of play in it and the cross feed has .015. This seems like a lot of movement for my needs.

    My use for this cnc conversion was to mostly turn hard plastic pieces with a stainless steel tube in the center for strength. These pieces would not exceed 6 inches in length or 2 inches in diameter. It would be required to take smooth accurate finish cuts for a decent finish that could later be buffed with out the need for sanding. It would also need to make a clean parting cut threw the stainless. The turret would allow me different tools for detail, parting and drilling.

    Sounds like I need to research ball screws.

    Thanks for the help everyone, it is greatly appreciated!

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    The rails seem to be in good shape and there is not any play between the carriage and the rails. The cross slide also seems to be in good shape.

    What I think I should research now is mounting the a ball screw to move the carriage and the cross slide. Then use gang tooling on the cross slide to keep it simple and lower the cost. The cross slide has about 7 inches of travel which I think will be enough for three tools.

    Does it sound like I might be on the right path?

  7. #7
    Community Moderator Al_The_Man's Avatar
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    What I did on a similar lathe was to obtain bearing mounts from Misumi US, and extend the BS shaft past the RH end to affix the pulley for 2:1 reduction, and I tucked the motor back under the centre casting.
    The hard part is usually getting a small dia BS to replace the cross slide screw.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  8. #8
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    Thanks that gives me some hope
    Would you happen to have any pictures? So far I have not found anyone that has converted one of these lathes.
    I was thinking about running the BS on the RH side of the cross slide. I assume this would give me more options for the BS.

    One of my biggest concerns at this point is my ability to convert this lathe. I worry that I will spend a lot of money on parts only to ruin a tired but functional lathe. I also worry that I will get part way finished and have to pay a lot of money to have custom parts made in order to complete the project.

    As this is my first cnc project, I have also considered getting a HF 7x and converting it with cncfusion. My concern with the 7x is the amount of travel on the cross slide. I don't know if there will be enough for gang tooling which is a must for the project.

    I have done some minor fabrication on my 4x4 such as cutting, grinding, welding and installing a new engine.
    List of tools I have that I think will aid in the conversion. 175 Miller mig, angle grinder, drill press, hand drill, drill bits, taps and dies, clamps, measuring tools. Sure wish I had a mill for making parts.

    What do you think I should go with for my first cnc project, convert the logan or the HF with cncfusion?

  9. #9
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    Here's a very simple conversion of a lathe in pictures:

    Tony Jeffree's Model Engineering Pages

    See here, some videos of a similar lathe, but with a more comprehensive conversion.

    cncyourmyford's channel - YouTube

  10. #10
    Community Moderator Al_The_Man's Avatar
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    Quote Originally Posted by LGentry View Post
    Thanks that gives me some hope
    Would you happen to have any pictures?
    This is on a 9"x30" Lathemaster.
    Same mounting at the Headstock end.
    Al.
    Attached Thumbnails Attached Thumbnails DSCF0180.jpg   DSCF0177.jpg  
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

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