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  1. #81
    Quote Originally Posted by routercnc View Post
    Looking really good, well done.

    Be aware that if you turn a stepper using a drill it will generate power (like an alternator or generator). If it is connected to the stepper driver board this can be a bad idea!

    For motor mounting plates you need to have slots not holes so you can tension the belt. 20mm or so slot is a good start but you'll need to decide based on the standard belt lengths available and making sure you can tension it. There are some online belt length calculators available so make sure you use those and place the centre of the slot in the nominal position.

    The motor plates are usually pocketed with the motor set into the plate allowing the drive belt to run free over the top surface. You've got the motor sitting flush with the rear surface so you are having to cut all the material away in the middle to allow the belt to run. Not saying your way won't work but its usually done the other way to keep some strength in the bracket.
    okay great I'll start working on that but if my plate is 20mm thick, the pocket depth would eat up the shaft length, so is it acceptable to have the pocket area maybe 10mm thick only for example?

  2. #82
    Quote Originally Posted by Noplace View Post
    okay great I'll start working on that but if my plate is 20mm thick, the pocket depth would eat up the shaft length, so is it acceptable to have the pocket area maybe 10mm thick only for example?
    Yes you only need a few mm to mount the motor. ..Clive
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  3. #83
    As Clive says you only need 2 or 3 mm, I've got about 3mm left for my Z stepper out of the 20mm plate...there's no real force acting on it so it doesn't need to be super strong.
    Neil...

    Build log...here

  4. #84
    Thanks I think I got it now, here's one of em with 5mm thickness for motor:
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  5. #85
    Spot on....
    Neil...

    Build log...here

  6. #86
    I have never found a pulley separation calculator that got it right. I draw the two PCD's at around the separation I want, add two tangents to connect them as the belt would, trim the circles to those tangents, list the two arcs and one tangent then tally their lengths. Undo until I am back at two circles, tweak the separation and start again until I get it near as makes no difference. If you mount motor and shaft bearing in the same piece of metal you don't actually need any adjustment if your machine is accurate.

    Make sure none of the pulley bolts coincide with the belt and if you are really canny you add a fixing for the plastic conduit that protects the motor leads, because that is never in quite the right place if you forget it now

  7. #87
    Hey guys, so just encountered an issue which is upsetting but hopefully with your guidance I can fix it. I didn't get a chance to take photos of the machine to show the problem but I'll explain it first now and hopefully post photos later if needed.

    so I connected the actual side plates to the X Axis rail and ballscrews:


    if you notice bottom 4 M5 screw holes are for connecting to the ballscrew nut bracket, this is the same screw you saw in the video, what happens is there is a mismatch between distance of the (4 M5 and 4 upper M8 holes) in the plate and the screw and rail distance so I have to lift the side plate a bit up to match the 4 M8 threaded holes and the when I screw everything fit the ballscrew is forced to strain upwards and causing me jittery movement if going slow along with noise and stalling at the far end side ( tested with drill just like video ) . it is opposite of result in video , very bad hopefully ill capture it but I don't want to repeat putting the sides haha.

    so my question, can you just solve this by machining the side plate to have the same slot solution as we discussed for motor plate?
    instead of 4 m5 holes ill have a slot of same radius but gives me little tolerance to adjust the height correctly?

    hope this is clear, if not I will post a photo of the real thing but the place I have my stuff in has no Air conditioner so I have to plan a shower after it haha.
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  8. #88
    You can slot holes so that you can have adjustment there's no problem there, of course it's better if they're spot on but once they're tightened up it won't really matter. I cocked up the dimensions on my Z back plate for the lower bearing plate for the Y axis and they're slightly slotted, it's still fine!!
    Neil...

    Build log...here

  9. #89
    After you have put in the slots and you get it all true you could then drill another hole through and put some dowels in to hold it in position. ..Clive

  10. #90
    one of the local workshops made it for me, will test and cross fingers and hopefully no more stress on ballscrews.

    on a separate note, back to the spindle I have tested it and seems to be working well with the relays and mach3, the speed is not being controlled accurately and I suspect the spindle pulley setting in mach3 but still didn't figure it out, ill post a video of this issue soon.

    but main thing about spindle is I ordered and received a braking resistor, its 200W 70Ohm as per the spec in the document. I know it's not needed but thought what the hell, I just have to revert the P14 setting the sylveski mentioned earlier and I think all the other default settings are good. if anyone wants to advice on this part please let me know.

    thanks!
    Last edited by Noplace; 06-07-2015 at 10:04 PM.

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