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Direct or Offset Z motors?

Discussion in 'CNC Mills/Routers' started by patdee, Nov 10, 2017.

  1. patdee

    patdee New

    Oct 31, 2017
    Likes Received:
    I am planning on building KYO's "Sphinx" CNC mill; with some modifications.

    C-beam Sphinx

    I downloaded the B.O.M. to order the parts. As I perused the list, I noticed that the "Z" motor mount was offset; and used pulley's and a belt. Thus it required that the motor be offset. But in my viewing of countless Sphinx "Builds", I noticed a number of times where they used direct motor drives; where the motor connected directly to the lead screw.

    If you would be so kind; would you care to state candidly; the" pros and cons" of both methods; before I order the parts.

    Thanks in advance for your doing this.

    Note: I apologize if someone has already posted this question. If so I hope "OpenBuilds" will delete this thread; for I have no intention of "upstaging" any one; especially since I am new to this great forum.

    Joe Downard likes this.
  2. Javit0

    Javit0 New

    Jan 2, 2021
    Likes Received:
    Oh man... 4 year later I hope that you were able to find the answer of your question. If not, I had the same thought and I was able to find in another post an answer that made sense from minimill (MiniMill Z Axis Upgrade with Offset Motor).

    - Lower overall machine height (In my case, this was my main driving factor: Wanted to fit the mill in existing shelf space)
    - Lower center of gravity - less vibrations
    - Easier to reach Z axis to manually turn (versus reaching inbetween motor and CBeam in the conventional setup) for manually adjusting Z Zero
    - Future: Reduction Drive (Pulley ratios) for even more torque

    - More parts (; - no biggie

    I will probably stick with direct config. For me, the only Pro I see is lower center of gravity/balance center with the spindle in one side and the motor in the other side. I don't think I am that good in machining yet.
    Peter Van Der Walt likes this.

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