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  1. #91
    Okay its sunday afternoon and I have spent an hour chopping wood. You know when you get what you think is a great idea. You rush in and draw it up and think...eerr i'm not so sure.

    I was concerned about getting good fixings in the box even though it is 6mm. Rather then pushing tubes through I came up with the idea of prespacing blocks along a threaded rod and pushing it into the box. Drill through and fix everything. You then have 4 end bolts to clamp up the sides.

    Your thoughts???

    Bruce

    Just decided that that idea is pants. Think I may have a better one.
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    Last edited by motoxy; 22-01-2012 at 07:43 PM. Reason: brain need putting into gear
    The more I know, I know, I know the less. (John Owen)

  2. #92
    Probably just have a block fixed each end for location and fixing. Drill the opposite side of the box where the rail mounting screws are along the centre line just big enough to hold the nuts to lock the screws through the box. This should not have a detrimental affect on the overall strenght of the box.
    I should probably now be thinking about buying some more parts. z rails and screw, motors and couplings. Then start getting some materials.
    The more I know, I know, I know the less. (John Owen)

  3. #93
    Well I think its about time to get my motors, drives etc. and couplers. I have looked at diycnc, zapp, cncrouterparts and cnc4you. Any others I should check out or any advice to be had? Probably have to buy the power supply in uk to avoid 110v.

    Bruce
    Last edited by motoxy; 24-01-2012 at 06:16 PM.
    The more I know, I know, I know the less. (John Owen)

  4. #94
    Last time I checked cnc4you was cheapest for steppers including postage (though it looks like that may have changed now) and eBay for the drivers. I'm not aware of any other places.

    The drawing in post #98 - You should make the joint between the X-axis linear bearings and gantry sides stronger. Currently it's only aluminium angle which will bend at the corner relatively easily, and since the bearings are free to rotate upon the rails that will cause deflection. Perhaps you could use box section there, or better just add some triangular pieces to stiffen it.

    Power supply - 500VA toroidal transformer plus bridge rectifier and capacitors is all you need. www.rapidonline.com are reasonably priced.

  5. #95
    Hi Jonathan, thanks for the heads up on the angle. hard to think I used to be a designer.. Currently being checked over for memory loss problems which probably explains a lot.
    I am going to start my build now. I am ordering material tonight as I think I can start moving forward now.

    How easy is a self built power supply???

    zapp have this as a kit http://www.zappautomation.co.uk/prod...547704f50af02c 316

    Do you think these are to cheap or worth a punt http://www.ebay.co.uk/itm/2508624928...ht_3191wt_1110

    Bruce
    The more I know, I know, I know the less. (John Owen)

  6. #96
    Thats it. Ally ordered.
    The more I know, I know, I know the less. (John Owen)

  7. #97
    Quote Originally Posted by motoxy View Post
    How easy is a self built power supply???

    zapp have this as a kit http://www.zappautomation.co.uk/prod...547704f50af02c 316

    Do you think these are too cheap or worth a punt http://www.ebay.co.uk/itm/2508624928...ht_3191wt_1110
    Very easy to make a power supply. Connect primary of transformer to mains via a fuse, secondary to bridge rectifier (e.g. bit excessive but you can't go wrong with http://www.rapidonline.com/Electroni...ctifiers-29671) and output of rectifier to smoothing capacitors. Minimum about 10,000uF, 80V or greater. Switch on and check the output voltage and polarity is correct with multimeter just to be sure then connect it to the stepper drivers.

    I tested a driver that looked identical to the ones you've linked to on eBay. I'd happily buy them if I needed some 50V drivers.

    Edit to add:
    Apparently it's not blatantly obvious this 4 line post isn't a substitute for proper research, so please note that this isn't a set of complete instructions but a general guideline.
    Last edited by Jonathan; 27-01-2012 at 11:48 PM.

  8. #98
    Okay I have purchased most of my main electrics. Jonathan was trying so hard to save me money but to be honest I was not happy building my own psu. I decided that I would get all my parts from one source in the UK so I could have a warranty and tel support. cnc4you are the lucky recipients of my dosh. I had a long talk with Brian and feel very confident.

    I have some parts being made by a very kind young gentleman, I wont mention that its Jonathan as I do not want to embarrass him.

    So by the end of this week I should have enough parts to begin the build, again. Hopefully this time, after all your good advice, properly.

    Ooo i'm so excited.

    Bruce
    The more I know, I know, I know the less. (John Owen)

  9. #99
    Quote Originally Posted by Jonathan View Post
    Very easy to make a power supply. Connect primary of transformer to mains via a fuse, secondary to bridge rectifier (e.g. bit excessive but you can't go wrong with http://www.rapidonline.com/Electroni...ctifiers-29671) and output of rectifier to smoothing capacitors. Minimum about 10,000uF, 80V or greater. Switch on and check the output voltage and polarity is correct with multimeter just to be sure then connect it to the stepper drivers.
    Jonathan I,m sorry but I'm not happy with your reply and I've got to say something.

    Your flippant answer regards transformer and capacitors/rectifier is very dangerous in the wrong hands and your putting folks in danger of either blowing up there drives and worse still potential to KILL them selfs.:surprised:

    They need to know that yes while it's not difficult to build a transformer supply it does have to be done correctly and components correctly sized to give the correct output they require.
    They need to know that the transformer seconderys need to calculated and sized correctly so when rectified from AC to DC they get the correct output so doesn't fry there drives.!

    They need to know for stable performance the capacitence should be calculated in relation to V & A required, to say just use anything bigger than 10,000uF is far from ideal.!!
    They also need to be aware of the very big potential to KILL them selfs if they dont treat Big capacitors with respect.
    They should also be made aware of the need to build in a capacitor drain to be absolutly safe when working on the control box, and that regardless of whether the box is plug in the wall or not that with out a drain system built in then there at risk of being fately electricuted if touched in the wrong place.!!

    They need to be made aware of other factors regards rectifiers, like they should really be mounted on heat sinks also how they are wired and they have positive and negative output.

    Folks It's not difficult but it's not just simply grab any old transfromer and capacitors and stick it together with a recitfier like Jonathan makes it appear.!!
    It needs to be calculated correctly for correct output and as always when working with electricty treated with utmost respect.

    While I know how to size and build one I won't post the information in thread like this because of the potential for error then blame.!!
    I will gladly help folks on a one to one basis via email or preferably on the phone/skpe because I can explain and control better that it's done correctly. Just won't do it in public.!!

    The information regards sizing components correctly is available on the net if you search. But please be sure you fully understand before attempting other wise you risk the BIG possibilty of destroying your drives or Worse your self if you get it badly wrong.:confused:

    EDIT: Jonathan dont bother coming back at me because you can't really and I'm not getting into another thread hi-jacking slanging match just needed to be made clear for the sake of others.

    Bruce I'm sorry for wasting more of your thread space.
    Last edited by JAZZCNC; 27-01-2012 at 09:02 PM.

  10. #100
    I'm allowed to have an opinion as well. Any DIY project like this involves an element of risk. I assumed that taking elementary safety precautions was contextually implied, and if I was wrong to assume that on a forum like this I apologise. I have added some wording to make this clear now.

    Just for the record, the mains part clearly is dangerous, but for the rest of the PSU wikipedia sums it up nicely:

    Quote Originally Posted by Wikipedia
    Voltages of greater than 50V applied across dry unbroken human skin are capable of producing heart fibrillation if they produce electric currents in body tissues that happen to pass through the chest area.
    10,000uF capacitors are perfectly fine for motoxy, as I said before more would be nice. I can only put my hands up and laugh that you would argue about something this elementary with someone who studies electrical engineering and has the same capacitance in both of his PSUs working fine without problems.

    If motoxy hadn't bought the parts already I would have happily soldered them together for free and sourced the parts, it would have taken at most 15 minutes.

    So after that completely unnecessary attack on my post, you know what? I think I will bother.

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