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New 20mm V-Slot Gantry Plate Design Flaw

Discussion in 'General Talk' started by DistortedDesigns, Feb 1, 2015.

  1. DistortedDesigns

    DistortedDesigns Journeyman
    Builder

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    I wanted people to know there is a design flaw in the 20mm V-Slot Gantry Plate. Link
    You can't mount a nema 17 stepper to it the way it is made. Even though is shows it in the examples you can't (at least not with out some alterations) and where they have the motor plate placed the holes don't even line up.

    1st issue is the edge of nema 17 motor plate runs right through the center of the wheel bolt heads. Download the
    More linear belt examples_3a.skp file located here

    20 mm plate.jpg

    Even if you could bolt it where it is shown the motor would be cockeyed.

    2nd issue is the motor plates shown mounted location. The holes don't even line up. The plate would have to shift down where it would hit the other 2 bolts heads and the belt is too close to the rail. So shifting up is the only real option.

    I have a fix to make it work but it's not super pretty.
     
  2. Rick 2.0

    Rick 2.0 OpenBuilds Team
    Staff Member Moderator Builder

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    Outside slots are 3mm so moving the wheels out is not really an option and shifting the plate down is not an option because the shaft hits the edge. Adding a couple spacer washers between the plates would raise the plate above the bolt heads but could potentially allow wobble. Personally, I would just invert a couple 6mm M5 screws and place them into vacant holes in the motor mount plate, trapping the heads between the two plates causing them to act like spacers.
     
  3. DistortedDesigns

    DistortedDesigns Journeyman
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    I put two small notches in the motor plate so i had access to bolts below so i could tighten the wheels. I just added two small washers on each of the 4 bolts in between the two plates to raise the motor plate just above the bolt heads. It is nice and stable because it is supported on 4 sides. Kinda a pain to assemble but does the trick for the least amount of money.
     
  4. Mark Carew

    Mark Carew OpenBuilds Team
    Staff Member Moderator Resident Builder Project Maker Builder

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    Not a design flaw. I just use shims to raise above the low profile screw heads to give a great strong mount.
    Or like Rick stated you could tap as well.
    Mark
     

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