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  1. #101
    Quote Originally Posted by JAZZCNC View Post
    Nah too expensive try these people or go to your local bearing supplier as they are often cheaper and will sell without Vat for cash.
    Timing Pulleys

    Your gantry is looking slightly better but still needs work. Also by the looks of it you haven't given much thought to how the ballscrew end bearings will mount and how the motor will connect.? Has it stands now it can't be done without special machining and using FF/FK bearing blocks.

    10mm plate would be better for the bearing plate 6mm is still a bit flimsy.! Can't afford any flex or resonance here.

    Do you have any SW fil;es for the pulleys? what Pulley width? Im assuming 16mm should do it? That belt must be very strongi guess? When the gantry comes to a sudden stop wont its inertia and the belt cause it to pendulum a little?

  2. #102
    Right, I have beefed up the gantry quite a bit now, Though the problem IM having now is difficult access...

    As you can see from the pictures below, having mounted the block the ballscrew doesnt extend far enough so i though i could add a coupler than add some 6mm rod which will go on one end of the coupler and the other end, the pulley. Pretty complex way so unless you guys say thats ok ill scrap that idea... would also need to cut a whole in the vertical box section to be able to tighen the coupler

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  3. #103
    How's your ball nut on the gantry going to connect to the Z axis? The way youve got it its going to be impossible to connect...

    Sent from my Galaxy S5


  4. #104
    Yeha i know haha, did that at like 7 right out of bed thus was a design that cant be done haha. They will be behind the horizontal box sections :)

    Is the pulley mounting system ok? Or in need of a severe redesign?

  5. #105
    It might be easier to use one large piece of box section for the gantry. Something like 150mm by 75mm, that way you have one nice flat surface after expoxy leveling to mount all your rails and ballscrews bearings. You also need a way of tensioning the motor and pully belt, slots in the mount would be fine. You might want your slots in the same axis as the center to center of the motor and pulley?

    Another thing, you want to keep the pulley on the ballscrew as close to the bearing as possible.
    Last edited by gavztheouch; 07-06-2014 at 11:31 AM.
    CNC routing and prototyping services


  6. #106
    Another thing, you want to keep the pulley on the ballscrew as close to the bearing as possible.[/QUOTE]

    so now coupler as a way to extend? :/ If so that allot of travel lost in the y axis... as i would need to bring everything closer but keep machine dimensions similar..

    i think the best thing to do is a gantry re design perhaps??
    Last edited by FlyHighRC; 07-06-2014 at 11:37 AM.

  7. #107
    Check out the other builds and find something similer that works
    CNC routing and prototyping services


  8. #108
    Wal's Avatar
    Lives in Stockport, United Kingdom. Last Activity: 06-09-2018 Has been a member for 6-7 years. Has a total post count of 387. Received thanks 41 times, giving thanks to others 18 times.
    >as i would need to bring everything closer but keep machine dimensions similar..

    Ahh - compromise!

    Hey man, reading through the thread I can see you're very keen to get this done, you're having to take a lot on board in a very short space of time and you have the self-belief - all of this is EXCELLENT. You can get something good built for the money you're talking but given that it's your first build, you just can't rush it.


    You can have two of the above..!

    It is possible to over-think things and there does come a time when you have to take the plunge and just start building, but to put things in to perspective - I spent about a year (more, in fact) on my current machine (most of this was going back and forth design wise) and as it stands it weighs over 100KG (without the base) can cut aluminium/brass quite comfortably and accurately (for my needs: 0.05mm) and has a working area of around 200x200x150mm. I'm happy with it, but there are certainly things I'd do differently if I was making it over again.

    What I'm saying is this - if you head down rush into it you may as well buy one of those machines in your original post. It needn't take you as long as what my build took me, but don't expect to have this done within a few weeks.

    Have a look at how your grandad works - is he any good? I'll bet he works thoughtfully and steadily if he is...

    Just my two cents.


  9. #109
    Can I just say you clearly haven't been doing much research despite your claims that you have.? Why because if you had been looking carefully you wouldn't have made so many errors regards mounting things and the COCKUP with ballscrew running thru those supports shows this clearly.!

    Your just wasting time at the moment because your not looking at the details and it's the details that matter most. Anybody can fudge together an outline of a CNC machine but building one requires certain Details are 100% correct and your not seeing them because you haven't looked/read closely enough at other builds. Asking questions is good an I encourage it but asking questions that are clearly in other threads that you have been advised to read is just lazy or you haven't done what you said you had.!!

    I'll give you this one last bit of info which you should have seen from other builds then I'm not giving anymore I see which should have been obvious in other threads pointed out to you.!!

    15mm wide timing belts, HTD series 5mm pitch no less than 18T pulleys because there isn't enough material left on boss for decent Grub screws after boring, plus better tooth engagement. I use 20T all the time when 1:1 ratio and 18/36 when 2:1

    Now go back to reading other threads and start paying attention to the details.!!

  10. #110
    Quote Originally Posted by Robin Hewitt View Post
    I must be misreading this, I thought that Jazz and me would see eye to eye about routing aluminium, I did go to Specsavers so it can't be that.
    No Robin we don't agree at all. I'm referring to the machines suggested lower down but your still banging on about that old chest nut that Routers can't cut aluminium properly.! . .Which is frankly stupid because there are many of us on here that do it quite nicely thank you.!

    Agreed on the concrete machine thou, correct Concrete and epoxy can make a very solid machine.!!

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