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890KV OX RC spindle

Discussion in 'Other Builds' started by Robert Hummel, Jan 13, 2014.

  1. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    1/4"x2 1/4" (4" OAL) is fairly easy to find https://www.google.com/shopping/product/16267331210206391260?espv=210&es_sm=122&biw=1920&bih=1017&output=search&q=1/4" foam cutting bit&oq=1/4" foam cutting bit&ei=c7veUsu6IOWN2gXC_4G4DA&ved=0CH0QpiswAg

    If you want longer, you will probably have to go up in diameter.
     
    JustinTime likes this.
  2. Nick Lancaster

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    Well I stand corrected on the 1/4in shank diameter :D
     
  3. The Dude

    The Dude Well-Known
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    DOH! Someone beat me to it. But now I know I definitely want 1/4" ER collet tool holder and not 1/8".
     
  4. Robert Hummel

    Robert Hummel Custom Builder
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    I would get both as you can get a 3 piece kit off eBay for a good price and it will open your bit selection ;)
     
  5. The Dude

    The Dude Well-Known
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    Getcher motor runnin'. Here's the wiring diagram I used to get an Arduino to make the motor spin at various speeds. Oh man I messed it up. The white wire goes to the pin9 and the black goes to GND. sheesh. Motor Wiring.jpg
    Just a word of caution, these motors are extremely dangerous. I have mine bolted to a board and the board is clamped to my desk. I tried to run it without bolts/clamps and it took off like a wheel and almost smashed my monitor. You have been warned...
     

    Attached Files:

    #35 The Dude, Jan 21, 2014
    Last edited: Jan 22, 2014
  6. The Dude

    The Dude Well-Known
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    Almost there.
    Spindle v 1.jpg
     
  7. Robert Hummel

    Robert Hummel Custom Builder
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  8. Public Do Omens

    Guest Builder

    This is why when we build quad copters the opposite side goes in reverse.

    To balance the torque.

    Hold the motor in your hand and feel the head torque.

    This is why i have my Z axis down the middle of my spindle shaft. In relation to X,Y moving parts.
    Others might find this method allows for better torque control, as it is more balanced being on the Z - Axis center.

    When you move the Z Axis from the X, Y you are exaggerating the torque effect.

    Hold motor turn on, hand close to body. Then move the arm to full length turn it on, harder to control. You see.

    I think it is torque acting on a lever, when it should rotate around the spindle center @ x, y location reducing this lever effect to ZERO.

    :cool: interconnect.me.uk
     
    #38 Public Do Omens, Jan 31, 2014
    Last edited by a moderator: Jan 31, 2014
  9. The Dude

    The Dude Well-Known
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    Yep, with washers on both ends. I left off the lock-collar for now and will make a clamp the same way they make scope mounts... maybe 6 screws holding it onto the v-slot. I'll have to add a right-triangular brace in the future to keep the vslot from flexing.
     
  10. Public Do Omens

    Guest Builder

    Is it not true if you reduce shaft length on the tool then you get less flex in the tool doing the work?

    This is what i would do, reduce errors by reducing long parts to shorter parts that have less flex. :cool:
     
  11. The Dude

    The Dude Well-Known
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    Yes, but the shafts you can buy are always long. The motor bearings are weak and can't handle a side-load so we use the extra shaft to add bearings and then the bigger bearings are coupled to the z axis. The actual distance between the tool and the mount is maybe 2cm. The top of the motor spins freely and the bearings all the way down are fixed to the machine. But yeah it kinda looks like this big long thing which is connected at the top so it has a huge torque radius... but that's not the case, depending how you mount it.
     
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  12. The Dude

    The Dude Well-Known
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    Hey dudes,
    So I am getting ready to make all this and wanted to run it by you all to make sure it will work. I've got a double-fluted solid carbide bit with 1/4" diameter(6.35mm), some aluminium from the recycling centre (plate=12mm or 1/2" and block=37mm or 1.5"), and my spindle is mounted very cheaply with some bearings, hose clamps, and a steel plate at the top. I plan to use foam to test it and then maybe some wood and then finally this aluminum.
    Spindle parts.jpg
    Spindle v2.jpg
     
  13. ThinkerTinker

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    Great build Sir!
    :)
    This just up my alley
    angle.JPG


    Iv worked with brushless motors for over a year for "non-RC" applications. This homemade electric longboard is what introduced me to DIY side of life :D I weight 150lbs and can get 27mph out of this little motor (25.2volts and 200A ESC), don't underestimate these little buggers, they'll nock your teeth out.
     
    Mark Carew likes this.
  14. Robert Hummel

    Robert Hummel Custom Builder
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    That is just awesome bud!
    As they say size don't always matter lol
     
  15. The Dude

    The Dude Well-Known
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    dang this aluminium is tough to mill. I had the feedrate way down to 100mm/min and it chattered the machine to the point of slipping steps and flexing the gantry. I believe 5ipm=127mm/min... so maybe I can try again at 20mm/min but now the v-slot wheels on one part have a little play that can't be taken up by the eccentric spacers... Does this mean the wheel is hosed or the hole is off or the screw is bent or what?
     
  16. Robert Hummel

    Robert Hummel Custom Builder
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    A lot has to do with the bit, also the way your spindle is mounted.
    Not knocking ya in any way I feel you jumped into aluminum a little to quick.
    Where and how are the esentrics installed "plate? V-grove channel?"
    Odds of the bolt bending are low
     
  17. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    If the spindle is bucking in any, the bit will bounce rather than bite. You shouldn't be having to push anywhere near as hard as you are. Maybe it's time to rethink the mount.

    Have you successfully done any plunge cuts with the bit? (assuming it is plunge capable)
     
  18. The Dude

    The Dude Well-Known
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    I cut some pine with ease and it came out clean and smooth. Go too fast and it chatters. I guess the bit was bouncing like you said. I don't have any other way to mount it except like Robert did with the angle bracket and no bearings but I was trying not to burn out the bearings on the motor. Sigh, guess I can remount it...
     
  19. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Consider cutting a V-shaped notch in a couple blocks of wood and wedging them behind it. Cinch it down into the notch and that will give you a good grip with minimal contact so you can still easily dissipate heat.
     
  20. The Dude

    The Dude Well-Known
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    What about making the mounts out of plexiglass? I think they'll hold together long enough to mill some aluminium replacements...
     
  21. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Any material is probably fine, the main goal is just to get it wedged into something with a wider spread to stabilize it. Notice how Mark has the spindle wedged and tightened into a V-shaped support on the OX build.

    [​IMG]
    Photo credit kram242

    It's mainly your lower mount that appears suspect, but it wouldn't hurt to apply the same principle to both. Once it's solid, you still have to deal with the play in the wheels.... Sorry, no suggestions there.
     
    #51 Rick 2.0, Feb 21, 2014
    Last edited: Feb 21, 2014
  22. Mark Carew

    Mark Carew OpenBuilds Team
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    Robert the last pictures you posted look fantastic! Well done :thumbsup:
     
  23. Robert Hummel

    Robert Hummel Custom Builder
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    Ty bud! :D
    It's really solid, I have 30mm M5s holding it.
    The bearing plate is going to sandwich between the 2.
    Just hope it comes together the way I have it planed out in the head :rolleyes:
     
  24. Mark Carew

    Mark Carew OpenBuilds Team
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    I think its build like a tank and I would think thats a good thing for a spindle.
    3-30mm M5 its not going anywhere! :)
     
  25. Tweakie

    Tweakie OpenBuilds Team
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    Excellent project build Robert - that is going to be a great little spindle. :thumbsup:
    Is there any form of locking between the rotor and the shaft or is it just a press fit ?

    Tweakie.
     
  26. Robert Hummel

    Robert Hummel Custom Builder
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    Ty
    Yes there are 2 m3 set screws in the motor housing, so them along with the snug press fit I don't see any issues.
     
  27. Yusuf Tumer

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    Are these types of spindles significantly quieter than a trim router? Also, would it be possible to mill Aluminium with this type of spindle if you made light passes?
     
  28. Robert Hummel

    Robert Hummel Custom Builder
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    To your first question I'm not sure as I have never used a trim router, to the second question yes, I have milled 3/8 plate @1/64 passes :)
     
  29. Yusuf Tumer

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    Thanks Robert. Your build looks great. I might replicate it for my OX eventually.

    By trim router I meant a hand held router similar to the one kram uses :)
     
  30. Robert Hummel

    Robert Hummel Custom Builder
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    Aww ok lol
    I would say just as hard on the ears maybe a little less
     

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