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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. [email protected]

    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.

    [email protected]

    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.

    [email protected]
  7. Ian Godfrey

    Ian Godfrey Well-Known 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?
  20. Ian Godfrey

    Ian Godfrey Well-Known Builder

    Big thanks to Daz, Chris, and Duncan.

    Here's a few shots of Daz's upgrades with new plates fabricated by the awesome Chris Laidlaw. Going to start making cuts very soon once I get the spoiler board installed. Chris's plates are the unpainted aluminum ones as well as the spindle mount, the black ones are from the original SMW3D kit that I spray painted so please excuse my "not so hot" paint job. For anyone considering the upgrade, it is very easy to install, this is my first CNC build and I found it easier than the stock kit and actually helps keep the wires nice and clean. It also makes the machine much for rigid and reliable over belts. A very affordable and easy upgrade, I'd love to see more of these offered. Oh and the gantry stiffening plates are from Ooznest who were kind enough to sell me a set of just those.

    For Chris's plates go here:

    OX Lead Screw 6 plate Upgrade Kit (seen at Openbuilds) | eBay

    01.png 02.png 03.png 04.png 05.png 06.png
  21. crispin

    crispin Well-Known Builder

    What's a nice set of plates like yours doing listed in such a sketchy category?
    Listed in category: eBay Motors>Parts & Accessories>Other
  22. CRG Au

    CRG Au Well-Known Builder

    Hi Ian. Photos look great mate! Can I ask, what are your x and y axis lengths are and are all your lead screws the standard openbuilds 8mm?

    Just ordered a set of plates and a mount off Chris. I'll be upgrading my Ox shortly. Any advice would be greatly appreciated!

    Chris Laidlaw likes this.
  23. Ian Godfrey

    Ian Godfrey Well-Known Builder

    Hey Chris, sorry for the late reply. Thanks for the kind words!

    My x axis is 750mm and the y is 1000mm. So yes I bought 3 full length acme lead screws (8mm) from Openbuilds. I also picked up the bearings and lock collars there too. Oh and the anti backlash nuts as well.

    Advice wise, what I did was put Mr. Laidlaw's amazing plates onto the frame and placed the anti backlash nuts onto the lead screws approximately half way along their lengths and mounted it between Chris's plates. I slid the gantry back and made sure that the nut and the y plate touched or was close enough to not cause the lead screw to flex. In my case, as with Duncan's I believe, there were precision shims on the wheel assemblies. The spacers are fine but the addition of the thin shim didn't work and actually are not needed at all.

    So I sighted down the rods to make sure the in and out of the screw (horizontal) was good and that the rod wasn't sagging (up and down). This might need a bit of propping up by a tiny bit, or maybe not depending on your length. If so, a block of wood works, freeing your hands for the next step. When I was happy, I marked the screw holes from the anti backlash nuts onto the y plates (scratch awl or pencil) along its centre axis as close as I could without getting too crazy precision wise. The not so fun part is taking it all apart so that you can drill these holes but it's not that bad. So drill them undersized and tap them! That way you don't need bolts on the inside face of the places interfering with their run. You just attach the anti backlash nuts with your m5's and are good. I drilled them on my drill press and just hand tapped them.

    That's it! Oh and I have the regular height z axis plate so I did the same thing with the x axis. There's a gap between the anti backlash nut and the z plate so people here were making their own 3d printed block to mount and pad out the gap. I made my own that woks for my machine. Duncan has one too in this post above. If you need help with that or if you or anyone wants the .stl for mine I can post mine too.

    Basically all you have to do is drill those y plate holes. I suppose if you modelled the whole thing you could determine their location this way but mine was already assembled so I had to tear it apart to make this mod anyway. The good news is this set up allows for wayyyy cleaner write management I find as well. A total win, win.

    And besides that, be sure to check Gaz's video.

    If you need anything else, please let me know.

    Chris Laidlaw and crispin like this.
  24. Troy D.

    Troy D. New Builder

    I'm in the process of building the ox metal, which uses 3-D printed parts for the Acme lead screws. I certainly don't see the 3-D printing parts as a weak point, as all they really do is hold the Acme lead screw in place. The real rigidity comes from the aluminum extrusions.

    From what I'm seeing, and I'd like for you to confirm on your own machine, is there is a fair amount of movement in the z-axis fore and aft. I tightened up my rollers as much as I dare, but there still is some flex in the Z axis. I'm using the double 20 x 60 extrusion which I think is standard on the Ox, along with another 20 x 40 at the rear.

    Since I had to buy 1000 mm maker rails and Acme lead screw, I decided to extend the width from the stock 750mm to 1000, and perhaps that was a bad idea? I would like to know on your particular machine how much flex you have fore and aft on the Z axis. I'm using a 1.5 kW spindle, and looks like you have a 2.2, so even heavier.

    I'm using the gantry plates from Chris, which I believe are 6 mm. Everything he machines seems to be top-notch, but I'm not quite convinced that plates that hold the Acme lead screw would provide much more rigidity than three the printed parts. As I mentioned, the rigidity doesn't come from the lead screw at all.

    I'm thinking it would probably take 20 x 80 doubled up, and more rollers to really stiffen things up more. I've yet to do a bunch of cutting with this so I'm not sure how much of this is a real issue in actual cutting. If a person was to make a final pass full depth, and only take off a thousandths of an inch, it could largely compensate for some of the flex.

    Now, as far as getting a flat bottom in a pocket, I don't know. Essentially the more the bit plunges in and out of the piece or otherwise loses contact with the work piece, the more the movement would be noticeable in the output.

    I'm very curious what you found on your own machine.


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