Cheap ballscrews - your advice/experience?

Discussion in 'CNC Machines and Conversions' started by Simon0362, Jul 12, 2010.

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  1. Jul 12, 2010 #1

    Simon0362

    Simon0362

    Simon0362

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    Hi All,
    I am about to add ballscrews to my existing BF20 CNC conversion (working pretty well on the combination of steppers, original screws and some home assembled electronics as well as Mach3) and I am bemused by the price differences between what is available.
    I can source (from linearbearings.com) a set cortresponding to what I think I need (X: 1605 x 600, Y:1605 x 390, Z: 1605 or 2005 x 600) for around 150€ which are shipped directly from China. All other souirces (e.g. ArcEuroTrade in the UK want the same amount of money for a single ballscrew.

    I am aware that 'you get what you pay for' but there is also a point where the cheap item is good enough for the job in hand - I am not working at aerospace tolerances and can accept some quality issues and I am also on a budget.

    Has anyone else gone down the linearbearings route or any similar supplier or is the general experience to pay more for some guarantee of quality?

    Your thoughts much appreciated.

    Regards,

    Simon
     
  2. Jul 12, 2010 #2

    Tin Falcon

    Tin Falcon

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  3. Jul 12, 2010 #3

    rcfreak177

    rcfreak177

    rcfreak177

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    Hi Simon,


    I have actually purchased ball screws from Linearbearings through Ebay some time ago,
    I have found the product to be extreamly good for the price and zero backlash. I fitted them to a 9x20 lathe which I retrofitted to cnc and the repeatability is excelent. I would definately buy them again. The shipping was around 2 weeks to Australia. The funny thing is I have Thompson ballscrews on my cnc mill, they sound crunchy and have approx .004" backlash, mind you they are the budget model (which is still triple the price of the ones from China). I will be soon fitting the Linearbearings screws to that machine as well. Here is the link to the store.

    Regards Barry.



    http://stores.shop.ebay.com.au/linearmotionbearings__W0QQ_armrsZ1
     
  4. Jul 13, 2010 #4

    Davo J

    Davo J

    Davo J

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    Hi Simon, I would recommend them.
    I bought my ball screws from them as well. The cost to buy them in Australia was $1800 plus post, linearbearings price was $640 delivered. I bought 25/5mm screw and 2 nuts per axis to load them up against each other. He does sell pre loaded nut's which have over sized balls in them, he calls them anti back lash nut's which is the way to go for single nut's.
    I have inspected them and found no faults at all and they are nicely finished.
    The are spoke of highly over on the CNC zone, with a lot of people using there ball screws, linear rails and also there air and water cooled high speed spindles.
    Some times cheap is nasty, but in this case it's not.

    Dave
     
  5. Jul 16, 2010 #5

    Simon0362

    Simon0362

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    Thanks everyone for your advice - they are significantly cheaper than any other source for shipping into France so I was looking for the downside!

    Simon
     
  6. Jul 17, 2010 #6

    rcfreak177

    rcfreak177

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    Hi Simon,

    The only downside I can see with the linear bearings ball screws may be the shorter lifespan over the more well known brands. They are made from induction hardened steel and then flash chrome plated which is only around 0.001" thick. My biggest concerns would be flaking of the hardchrome or variation in hardness. In saying that I have had no problems. Obviously most products from China do not meet ISO 9001, 9002 standards but I do believe these days products are getting better due to the highly competitive international market. I am sure at the price the ball screws in question once worn out you could throw them away and purchase new ones. Best of luck.

    Barry.
     
  7. Jul 27, 2010 #7

    macona

    macona

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    I have used those screws and nuts on a torch lifter on a plasma cnc. I wouldnt use one on a cnc. They are considerably rougher than the higher quality rolled screws. These are truly bottom of the barrel screws.

    I have picked up good ground screws off ebay for good prices.
     

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