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  1. #11
    Fantastic build Jonathan, many thanks for posting

  2. #12
    Great looking build Jonathan, a real work of art.

    I'm only about half way through the first post, can't wait to finish reading it.

  3. #13
    Thank you for the comments so far.

    Quote Originally Posted by silyavski View Post
    Great machine and very informational build. I will implement some of your ideas on my next build, especially the system for oiling the bearings.
    Please feel free to copy or develop the design, that's the general idea. You can have a better look at how it all goes together when I post the CAD models, which will be soon. Sasha's just updating them first, as for instance the model still shows the rails on aluminium strips not epoxy.

    Quote Originally Posted by silyavski View Post
    I am slightly curious about the ceramic bearing spindle. From my understanding, if you / god helps no to happen/ hit the spindle by accident on the table or a part, what would happen to the ceramic balls? You say there is an electric contact. Maybe only the lower pair is ceramic?
    Yes that is a valid concern with ceramic bearing spindles, they are apparently more fragile. I'd come to the same conclusion with regards to which bearing are ceramic, but we're not keen on dismantling it to find out...

    Quote Originally Posted by silyavski View Post
    From where did you get that encoder for the spindle? Does your VFD support encoders?
    eBay, like this one:
    HEDS-5500#A06 - AVAGO TECHNOLOGIES - ENCODER, ROTARY, 500PPR, 2CH | Farnell United Kingdom
    Part of the reason we had to put a PCB with the encoder was because the cheap one from eBay lacked the index pulse. If you're feeding the signal into the parallel port (e.g. to implement PID loop with linuxCNC) then the frequency needs to be reduced anyway. Sasha's just using the standard cheap Huanyang VFD.

    Quote Originally Posted by mart154 View Post
    Does the epoxy "self level" itself to a finish that doesn't need any more work at all? Just mount the linear rails?

    Or was there more work involved?
    Yes and no. In the pictures I posted you can see I had already drilled and tapped the holes in the frame when we decided to use epoxy. This meant that we had to plug them with bolts, covered in grease to stop them bonding, and use a countersink bit to remove the meniscus left around each bolt. To get a more complete surface for the rails to mount on you could leave the drilling and tapping until after the epoxy has set, since as there is no glass in the epoxy it drills easily with standard HSS drills.
    Apart from that, no there's nothing else involved - it's a really easy process compared to the other options.

    Quote Originally Posted by deannos View Post
    "However if I made another one of these machines (I could be persuaded),"

    How much would persuasion cost
    The problem is not so much the cost, it's the fact I'm still at University so available time to make CNC routers is limited. It's hard to say exactly how much, as Sasha and I obtained a lot of the parts cheaply on eBay and I can't rely on doing that again, but as a very rough estimate I'd say 4k-5k for everything. Maybe less, probably not more. I'll post the breakdown of the cost of the components in the first post soon, just looking for some of the invoices first.
    Last edited by Jonathan; 31-08-2013 at 12:06 PM.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  4. #14
    I have another question about your design.
    The holes on the steel are for moving the bed up and down? So, how will you keep the original parallelism of the rails that move the gantry, shimming every time? Or using the supports i see on one of the pictures and shimming and adjusting in vertical position connecting the table to the supports instead directly to the steel frame?



    About the epoxy. You mentioned the brand. Where did you get it from? Abroad? How much epoxy was used? I have to do this very soon.

  5. #15
    Quote Originally Posted by silyavski View Post
    I have another question about your design.
    The holes on the steel are for moving the bed up and down? So, how will you keep the original parallelism of the rails that move the gantry, shimming every time? Or using the supports i see on one of the pictures and shimming and adjusting in vertical position connecting the table to the supports instead directly to the steel frame?
    The main reason for including an adjustable height bed is so that the machine can maintain sufficient rigidity whilst cutting tall and short parts. This machine is plenty strong enough to cut aluminium at a respectable rate even with Z-axis fully extended, so I don't think Sasha will be moving the bed at all often. When it is moved, it will either have to be skimmed or shimmed. Putting shims on the 7 aluminium support blocks that the bed mounts to is probably the easiest way. Also bear in mind the holes for mounting the bed were drilled accurately using my milling machine, so the error introduced by moving the bed should not be very large.

    Just to be clear, changing the height of the bed only affects the parallelism of the rails with respect to the bed. The measurements of rail straightness (and twist) we took effectively subtracted the error due to the non-parallelism of the bed, as once the bed is skimmed using the machine this error will be largely eliminated.

    Quote Originally Posted by silyavski View Post
    About the epoxy. You mentioned the brand. Where did you get it from? Abroad? How much epoxy was used? I have to do this very soon.
    It was from the UK - I contacted lots of different companies who sold similar resin to see if they could get the hardener. You might want to ask Clive S where he got his as he got some much more recently than I did. The company 'Desperate Measures LTD' quoted 24.48 for 1kg of resin and 17.61 for the hardener to go with it. I think those prices do not include VAT, but I'm not sure.
    I think we used about 600g of resin - I can't remember exactly. You can work out what mass of resin you need by just working out the volume (remember to include the bridge across the middle) and multiplying by the density they quote. About 4-5mm thick should be plenty.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  6. #16
    Quote Originally Posted by Jonathan View Post
    ... The company 'Desperate Measures LTD' ...
    You made my day.


    Thanks again for the information.

  7. #17
    Thats some thread mate,well you know im a fan of this machine,i saw it being built at various stages i used to stand there in awe lol just staring at it,its so busy,well done lads.

  8. #18
    Hi

    you could not have timed this better for me, am just about to start a build. I want quite a heave duty machine for milling stone/ally

    Question. Would there be a benefit from using larger motors Nema 34s or 42s or might it be a problem

  9. #19
    Quote Originally Posted by george uk View Post
    I want quite a heave duty machine for milling stone/ally

    Question. Would there be a benefit from using larger motors Nema 34s or 42s or might it be a problem
    For the machine in this thread, there would be no benefit - in fact it would probably make the machine worse. Larger stepper motors tend to not spin as fast, but output more torque. If the smaller motor can output sufficient torque to obtain the required aceleration and speed, there is therefore no point using a larger motor as it will just cost more and sometimes not go as fast.
    You would have to be building a huge machine for Nema 42 motors to be the correct choice. See this thread for a more detailed explanation.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  10. The Following User Says Thank You to Jonathan For This Useful Post:


  11. #20
    thanks, am reading that now. Brilliant stuff.

    I have another 2 questions or request for your opinion.

    1. To stiffen up Z and Y ( when in action together ), i was thinking off adding rails to the inside edge of the X top support. ( i may want to add an impact head to it in the future ). Any opinions ?

    2. any idea when the files will be available, am eager to have a crack at this.

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