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Project Ox Upgrade Kit 06-05-2017

Beef Up The Ox

  1. Chris Laidlaw

    Chris Laidlaw Journeyman Builder

    Hi Guys,

    Daz agreed that I can make and sell these kits. Daz, please let me know if the situation has changed.

    Please email me if you would like a set. chrisclub@gmail.com

    I have not yet programmed and designed the fixture plates or programmed any of the parts, but 2 people have made inquires so far.
    It will probably take me 3 full days to make the first set.
    The plates will be made from .26" thick (6.6 mm) 6061 T6 Al.

    I plan to only make the parts that are not available at the Openbuilds store.

    P.S. I have a store on Ebay for other CNC parts:
  2. Duncan Smith

    Duncan Smith Well-Known Builder

    Quick Y axis update, trying variations of Daz's design. Prototype showed idea of a mount plate for the acme nut is probably not good; it moves the nut out, forcing the motor further out, which allows for a bit more flex, certainly with acrylic prototype. Also prototype used 3 of the existing motor mount holes, I didn't like the look of the leverage on those. So I'll go with what I think Daz has done, which is drill and tap the existing Y plate for the acme nut. Actually easy to do in situ without disassembling the machine (assuming holes are arranged to line up with the slots). One less component. (Fusion is playing up with the online link or I'd share the design for the curious).

    For the motor mount, I'd prefer four screws to the three Daz has used for the motor, and I'll not co-locate with the v-slot screws (assuming I understand the design correctly). Also, the point about having clearance to drill for the acme nut - easier if located with the slots.

    I think with the motor screw going into the v-slot hole...there must be about a mm out horizontally - do you have a bit of a lateral bend in your acme screws, Daz? That or your y plates are a mm thinner than mine.
  3. Chris Laidlaw

    Chris Laidlaw Journeyman Builder

    Hi All,

    I have started designing fixture plates to make the 6 plate set... I have simplified the X extender plate and made its 4 stepper holes M5 tapped.
    The bearing holes on all plates will be press-fit... .630" -0"/+.001". See attached .dxf

    All plates will be 6.6 mm thick (.260") 6061 T6

    The only Daz files I see are the 1/29/17 version, I hope the only change since then was the thickness.

    I hope to start cutting parts tomorrow, so if anyone sees a problem, please let me know.

    The 6 plate set will be $170 Friends and Family plus shipping.


    Attached Files:

  4. Chris Laidlaw

    Chris Laidlaw Journeyman Builder

    Hi Duncan, I like your ideas.

    I did notice a few minor issues with the Y stepper plates... the spacing is a tiny bit off.. .7774" vs .7874".
    Also, not sure why the transition from horizontal to vertical holes is not exactly 20 mm apart.

    I like using all 4 motor mounts... but I think it would be better to keep them co-located with V-slot holes and tap the top hole in the v-slot. The 4th motor hole bolt would just go into a hollow in the v-slot if it was too long. I like the idea of using existing holes in the Front X plate for the new acme nut, so the rod should be centered on the X front plate between it's wheels.
  5. Duncan Smith

    Duncan Smith Well-Known Builder

    Here's the issue with the Y motor mount plates:

    If you co-locate the motor screw mount with the v-slot holes, the centre line for the motor is 23.5 mm from the centre line for the v extrusion, for 47mm nema23 mount spacing.

    If you mount the acme nut directly on the gantry plate, the centre line for the acme screw is 25mm from the centre line for the v extrusion (I measure a 3 mm gap from extrusion to gantry plate, gantry plate thickness - which is 6mm thick for me- plus 6mm to centre of acme nut).

    So, 1.5 mm out. 1.85 if you have 1/4" thick gantry plates. This will be a significant bend in the acme screw near limits of movement.

    You can't shim your way out of that, though it might be possible to shave the 1.5mm out of the acme nut to make the difference. Personally I'd rather move the motor mount to match the given acme mount location.

    Test fit last night of a cut in acrylic confirms these sums (for my machine, yours may be different). Will post the design later.

    Shame you're not in Europe, Chris, or I'd commission a set in my design from you.

    Also, I think the design I posted for the X acme nut mount is a little thin, probably needs to be a little thicker.
  6. Chris Laidlaw

    Chris Laidlaw Journeyman Builder

    Hi Duncan,

    Thanks for the input! My plates are 6.6 mm thick, so I will calculate accordingly. I like the idea of mounting the nut directly to the Y plates.

    Do you still use a spacer to mount the nut to the X plate?

    I ship all over the world... in the last two weeks I shipped to Finland, Belgium, UK, Canada, New Zealand and yesterday Czech Republic.

    It is only $22 to $32 extra for shipping.

  7. Ian Godfrey

    Ian Godfrey New Builder

    Thanks everyone here (Daz, Duncan and Chris) ! Such a good group of minds. Duncan, do it! I got a router mount from Chris and it is impeccable. (Got an order on these too!) Really looking forward to this modification everyone.
  8. DazTheGas

    DazTheGas Veteran Builder

    @Duncan Smith

    So lets do some maths ;-)

    An assembled extreme wheel is 11mm, so the centre line that will sit on the v-slot will be at 5.5mm. so lets add a 6mm spacer which brings us to 11.5mm, and then a 6mm plate that brings us to 17.5mm. we need to add our acme which is 12mm so the centre of this again is 6mm, so we now have 23.5mm from the centre of the V-Slot to the centre of the Acme.
    Now a Nema23 stepper from the centre of the fixing hole to the centre of the spindle is 23.57mm

    So we are 0.07mm out. but you must remember that industry standard for stepper motors is + or - 0.2mm and not all spacers and plates are dead on.

  9. DazTheGas

    DazTheGas Veteran Builder

  10. Tracy Ranson

    Tracy Ranson Journeyman Builder

    I was wondering if you could provide these files in DXF format please.
  11. DazTheGas

    DazTheGas Veteran Builder

    Try this file out, ive never used DXF so not sure??


    Attached Files:

  12. Tracy Ranson

    Tracy Ranson Journeyman Builder

    This one worked out for me. Thank you
  13. DazTheGas

    DazTheGas Veteran Builder

    ok I will add all the rest later to the zip..

  14. Gerta

    Gerta New Builder

    Really excited to see all the activity on this upgrade. I'm glad to see the plates are now available from Chris (and maybe soon DazTheGas?) so we don't have to start from scratch with the shop on campus.

    DazTheGas, any chance you could post the details for drilling the OX gantry plates to accommodate the y acme screw anti-backlash nuts? Perhaps this is already somewhere in the posted info and I'm missing it.
  15. Duncan Smith

    Duncan Smith Well-Known Builder

    Thanks for the details, Daz!

    I think the discrepancy is in the spacers, I have an ooznest kit which has a 'precision shim' and a quarter inch spacer giving 7.2 mm measured from wheel to gantry edge, so I think I have an extra 1.2 mm over your setup? Enough for me to notice anyway.

    I've got the plates cut, ready to fit tomorrow and see how horribly wrong I've got it. Proof of the pudding...!?
    Sums come to 24.7 mm rather than 25mm, which is less than I'd notice.
  16. Duncan Smith

    Duncan Smith Well-Known Builder

    Hi Daz, Found your (quite excellent) video on the upgrade. Your gantry plates definately look to ride much closer to the rails than mine. So, note of caution for upgraders. Check the setup and measurements for your machine!
  17. Duncan Smith

    Duncan Smith Well-Known Builder

    So how's pudding? Moderately tasty. Some slight stress in the system, I think the acme screw centre line is ~24.56 for my machine based on measurements on the screw in situ, as opposed to the 25mm I've cut. I'll move the motor mount in by 0.44 mm if/when I cut new plates from aluminium.

    Also I think I've cut the holes for the acme nuts on the Y plates a little high (a mm or so), so I'll also adjust my plates for that. This was my concern with doing these manually, hence the aborted idea of a nut carrier to allow for adjustment:


    Reality is that the machine seems to be coping with the innaccuracies, partly thanks to the flexible shaft couplers, so it seems to work out ok without the adjustable mount.
  18. Duncan Smith

    Duncan Smith Well-Known Builder

    Plate, as modded for my machine and my lack of skill in measuring and drilling holes in aluminium:


    For the bearing mounts I just omit cutting the motor mount holes. I've left provision for a cross brace if rigitity is an issue, hence the extra 2 outer holes.

    With acme driver now in place, and having seen Daz's vid on aluminium cutting, I might have the confidence now to give cutting these in Alu a try.
  19. Synths

    Synths Well-Known Builder

    Is anyone interested in doing a 16mm ballscrew variant of this design?

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