584,798 active members*
4,244 visitors online*
Register for free
Login
IndustryArena Forum > MetalWorking Machines > Fadal > Spindle bearing preload
Results 1 to 7 of 7
  1. #1
    Join Date
    May 2008
    Posts
    2

    Spindle bearing preload

    Guys,

    The shop bought a fadal 6030 and i am trying to replace the spindle bearings....... how do you set the PRELOAD on the bearings? I have read a few people talking about setting them to 1500 PSI., but how would i acomplish that?

    Any info & help would be greatly appreciated!!!

    Chris

  2. #2
    Join Date
    Apr 2005
    Posts
    1194
    1) Place a Pressure Gage (SVT-0066) on the table and align it with the Spindle
    nose.
    2) Set an indicator on the Head and touch the indicator tip on the nose of the
    Spindle.
    3) Jog the head (Z axis) down until the pressure gage reads 1000 pounds.
    4) Zero the Indicator.
    5) Jog the head (Z axis) up until it is no longer in contact with the pressure
    gage.
    6) Depress the “Tool In Out” Button on the keyboard.
    7) Release Button.
    8) Read the value on the indicator.
    If adjustment is necessary on a adjustable spindle then turn the spindle
    preload adjustment nut clockwise to tighten and counter clockwise to loosen.
    Listed below are the "Fadal factory recommended specifications" for the
    various spindles.
    RPM Rating Preload setting: (Deflection at 1,000 psi. Lube Method
    15,000 / 10,000. 0014-.0017 (Can Not be adjusted) Air/Oil
    7,500 0013-.0015 (Adjustable preload) Grease Pac
    10,000 0013-.0015 (Adjustable preload) Grease Pac
    15,000 0017-.0019 (Adjustable preload) Grease Pac
    We have had good luck with our Fadals milling mostly soft steel and aluminum up to 5 axis. We are always looking for spare parts If you have a broken down Fadal give a shout.

  3. #3
    Join Date
    Mar 2003
    Posts
    4826
    In general, the actual preload on the balls is always very light. Where a huge number might come from is the tightening torque on a nut which is clamping inner race + spacer + inner race into a stack. This brings the races into position where they apply a light pressure to the balls. No matter how much more you tighten such a locknut, the preload on the balls will not change because the spacers are what create the preload, which is basically ground into the bearing at the factory.

    In a back to back or face to face paired bearing assembly, no spacers are used, of course, and the factory preload occurs when the races meet. But if the bearings must be seperated by the spindle design, then typically, both spacers would be exactly the same length, between the inner and outer races. It is possible to monkey around with the preload under these circumstances, by altering the length of one spacer relative to the other one.

    So, you may not know exactly what you have. When I rebuilt my Haas spindle, I made up the bearing and spacer stack and applied pressure to the stack with a plate on top, via use of a hydraulic press, and moderate pressure. From this, I could get a feel for the length of the outermost spacer relative to the inner one (which is not accessible in the stack). Now I went totally on a hunch and a bit of experience , but I lapped only one end of the outer spacer length carefully (with a lot of careful checking of the length to make sure I was keeping the ends parallel) until it took firm finger pressure to slide the outer spacer back and forth in the stack. That, I concluded, was the preload I wanted. It worked out well, too.

    Haas retains their bearings with shrink fit spacers, not nuts. So the actual preload on the stack is unknown. All I did was heat the spacer, drop it on the spindle and let it cool. Then, because it would be a little bit loose lengthwise after cooling off, I bumped it on tight against the stack with the press. One little pop sound occurred when I did this, indicating to me that the spacer had moved just a wee bit as it settled into final position.
    First you get good, then you get fast. Then grouchiness sets in.

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  4. #4
    Join Date
    Feb 2008
    Posts
    547

    Red face

    Quote Originally Posted by carbidecraters View Post
    1) Place a Pressure Gage (SVT-0066) on the table and align it with the Spindle
    nose.
    ...
    4) Zero the Indicator.
    5) Jog the head (Z axis) up until it is no longer in contact with the pressure
    gage.
    6) Depress the “Tool In Out” Button on the keyboard.
    7) Release Button.
    8) Read the value on the indicator.
    ....
    Carbide, I love your post... but this one confuses me (I'm old... humor me) If you jog up after zeroing the indicator, your no longer at zero, so how can you measure deflection?. What am I missing?
    Steve

  5. #5
    Join Date
    Apr 2005
    Posts
    1194
    Copied and pasted from Fadal TSM
    We have had good luck with our Fadals milling mostly soft steel and aluminum up to 5 axis. We are always looking for spare parts If you have a broken down Fadal give a shout.

  6. #6
    Join Date
    Mar 2009
    Posts
    100
    Set the indicator base on the side of the spindle, not the table.. This is how I envisioned it while reading the instructions, not based on facts, knowledge or experience.
    Hmm:
    If I had the facts, knowledge, and experience of how long it takes to become a good machinist-I never would have become a machinist. I would've chosen a job that you can master in UNDER 10 years. Thats why not having the facts is good, because now I'm a very good machinist!!(Did take 18 years though(and I'm still learning every day)

  7. #7
    Join Date
    Mar 2003
    Posts
    900
    Scanfab--
    I've been doing this kind of work for over 30 years. I even work for a machine tool builder and spent YEARS in the aerospace industry working on the machines myself. Sometimes I think I know nothing other times I realize I don't know everything I don't know!!!

    Neal

Similar Threads

  1. preload on spindle bearing
    By adryan in forum Uncategorised MetalWorking Machines
    Replies: 7
    Last Post: 06-21-2010, 11:59 PM
  2. THK HSR bearing codes, Factory preload?
    By mfisch2001 in forum Linear and Rotary Motion
    Replies: 3
    Last Post: 02-11-2009, 01:40 PM
  3. locknut for bearing preload
    By lagfish in forum Benchtop Machines
    Replies: 14
    Last Post: 01-11-2008, 10:57 PM
  4. Bearing Preload w/Lovejoy Connector
    By rcazwillis in forum Linear and Rotary Motion
    Replies: 21
    Last Post: 07-23-2006, 11:43 AM
  5. strange bearing preload thread on ballscrew
    By mxpro32 in forum Benchtop Machines
    Replies: 14
    Last Post: 03-22-2005, 08:23 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •