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Beginner here - Sparking inside the spindle

Discussion in 'CNC Mills/Routers' started by Jonas Hermansen, Aug 21, 2018.

  1. Jonas Hermansen

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    Hi all.

    I'm a beginner, so please bear with me.

    I have an OX inspired CNC with a Kress 1050 spindle and when I'm cutting plywood I often get some quite dramatic sparking inside the spindle - I'm assuming it's just the brushes on the armature, but is it normal?
    Cutting parameters e.g. slotting with a 6 mm two flute, with a depth of cut of 3 mm, spindle speed 25000 and feed speed 2500 mm/m.

    Is this pushing the spindle too hard?
    Please see image IMG_9461.PNG

    or a GIF GIPHY.gif
     
  2. jeffmorris

    jeffmorris Journeyman
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    Stop using that spindle. The brushes are bad.
     
  3. Jonas Hermansen

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    That's bad news. It should be reasonably new, less than 15 hours runtime.
    Is this something that can be fixed by installing new brushes?

    I should note that it only sparks under load.
     
  4. GrayUK

    GrayUK Openbuilds Team Elder
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    The Kress Spindle has a very good reputation for reliability and hardwork. It is very unusual for the brushes to be worn that quickly. I know they come with spare bearings, I thought they might come with a spare set of brushes. However, get in touch with the place you got it from and explain the situation, and they should offer new brushes for free in that short time of use.
     
  5. Jonas Hermansen

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    Thanks for the advice.
    I'll try to get the receipt from the guy I bought it from, so that I can contact the seller directly.

    What I think is curious is that it seems to only be a problem when the spindle is under "significant" load.
     
  6. GrayUK

    GrayUK Openbuilds Team Elder
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    This could mean that the additional stress is causing play in the bearings and the commutator is moving slightly causing the sparks to fly.
    Did you get the extra bearings with the unit, or is it second hand, so to speak? As I say, if you look up a new Kress on Ebay or wherever, you will see it usually comes with a spare set of bearings. I see this Company has the spares for Kress

    Milling Spindle Motors Spare Parts.
     
  7. Jonas Hermansen

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    I got it second hand, unfortunately - and I got neither extra bearings or brushes :(
    But a new set must be cheaper than a new spindle...
    According to the link you've sent it's double front bearings - is there normally no need to change the back bearing?
     
  8. jeffmorris

    jeffmorris Journeyman
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    If the brushes and bearings are bad, it's possible that the armature is bad. It's better to buy a new spindle than to fix the old one. If you still want to buy new parts, try this website: Kress Spindle | Midwest Circuit Technology
     

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