Results 1 to 11 of 11
  1. #1
    PeteM is offline Diamond
    Join Date
    Jan 2002
    Location
    West Coast, USA
    Posts
    5,043

    Default

    In the how-come-I-never-learned-this dept, what are precision gage balls best used for? These typically come in fractional sized sets of 3; they're basically precision ball bearings.

    I assume that 3 together can be used somewhat like precision parallels, but not sure of the advantages. I've also seen balls used to measure ID holes, but would be hard-pressed to see and advantage over adjustable ball-end hole gages or (in the usual case when both diameter and straightness are to be held) gage pins.

    So what unique application are precision gage balls best for? Is it just a matter of being able to hold size very close for not a lot of $$$ ?

  2. #2
    Rotate is offline Senior Member
    Join Date
    Feb 2002
    Location
    Toronto, Ontario, Canada
    Posts
    225

    Default

    I've seen these ball gauges used for measuring OD of a tapered shaft (micrometer won't sit flat), and in combination with a block gauge you can calculate the taper accurately. I guess they can also be used as a go/nogo type of gauge for quick inspection. I remeber borrowing a set from work and my kids had a field day with them, so they also make for a very nice toy for the children and big kids like me.

    Albert

  3. #3
    Pazuzu71's Avatar
    Pazuzu71 is offline Hot Rolled
    Join Date
    Dec 2001
    Location
    Live Oak, Texas
    Posts
    800

    Default

    Pete....This one's easy.
    I use these balls frequently.
    If you're making a tapered hole, (Cone shaped), and you need to check the depth/hole size,,,,,,
    you use 2 balls.
    One small ball inside the taper (Deep)
    And one big ball at the top of the hole.
    With simple math, you can figure out if the angle of the taper is correct.
    Depth of small ball + height of big ball =?
    By trig-ing out the answer, you instantly know the angle of your taper.
    Also handy for checking Dovetails, etc.

  4. #4
    PeteM is offline Diamond
    Join Date
    Jan 2002
    Location
    West Coast, USA
    Posts
    5,043

    Default

    Thanks! Measuring a tapered hole makes lots of sense. Any idea why they're sold in sets of three? I assume that's because 3 points establish a plane, but the practical application eludes me.

  5. #5
    Pazuzu71's Avatar
    Pazuzu71 is offline Hot Rolled
    Join Date
    Dec 2001
    Location
    Live Oak, Texas
    Posts
    800

    Default

    Beats me......
    I have no idea why they're sold in sets of 3.

  6. #6
    Kurt Westfall is offline Stainless
    Join Date
    Oct 2001
    Location
    Montrose Iowa
    Posts
    1,180

    Default

    same reason we have two .250 drill bits, .250 and letter E, go fuigure?

  7. #7
    WILLEO6709's Avatar
    WILLEO6709 is offline Diamond
    Join Date
    Nov 2001
    Location
    WAPELLO, IA USA
    Posts
    4,858

    Default

    I'd say they are in sets of 3 for checking radius grooves. Slip 3 balls of the proper radius into the "round internal o ring groove" and slip a gage pin between them to find the diameter to the inside of the balls. trig it out and you know your size. a little grease help[s for holding everything in place. Leo

    [This message has been edited by WILLEO6709 (edited 03-09-2002).]

  8. #8
    TheMetalDoctor is offline Titanium
    Join Date
    Oct 2001
    Location
    San Jose, Ca. USA "That light at the end of the tunnel just might be......"
    Posts
    2,244

    Default

    The gage balls are furnished in sets of three for inspection set up on a surface plate. Just like a four legged chair, one leg seems to always be shorter than the other three. A three legged chair would touch down on all corners. Uneven-ness in the flat area of set up parts ( even if they are supposed to be flat) will be taken up by the 3 point contact. Ever see a 4 legged tripod ? Yup, I think you've got it.

    TheMetalDoc

  9. #9
    PeteM is offline Diamond
    Join Date
    Jan 2002
    Location
    West Coast, USA
    Posts
    5,043

    Default

    Thanks, MetalDoc. That was along the lines of my assumption ("used like parallels" and "3 points for a plane"). In practice, it seemed to me that the work would be pretty wobbly sitting on 3 balls on top of a dead smooth surface plate -- hard for me to see the advantages over, say, spacer blocks. Is this method actually used much (maybe for things like castings with locating points or ?). With clamping is it ever rigid enough for machining??

  10. #10
    TheMetalDoctor is offline Titanium
    Join Date
    Oct 2001
    Location
    San Jose, Ca. USA "That light at the end of the tunnel just might be......"
    Posts
    2,244

    Default

    Set up balls are used all time in inspection departments. Sometimes they are used on top of a post which has adjustable height and a countersunk top. These same "jacks" are used in machining for set up when machining uneven castings where a block would not bite in the ball will. yes, they are stable enough for milling. Just like any mill setup , you have to clamp with enough pressure to keep the part from moving.

  11. #11
    PeteM is offline Diamond
    Join Date
    Jan 2002
    Location
    West Coast, USA
    Posts
    5,043

    Default

    Thanks!

Bookmarks

Posting Permissions

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