Grinding a flat face on a 1" ball bearing?
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 30
  1. #1
    Join Date
    Sep 2002
    Location
    Seattle, WA. USA
    Posts
    1,107
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    I've been reading and enjoying:

    Machine Shop Trade Secrets by James Harvey

    He has a nice idea for squaring, which uses a ball bearing with a flat that you put on one face of a milling vice giving a single point of contact on that face. I did not notice in the book - I must admit to scanning it - how one does such a thing. Any ideas? Being a ball bearing is hard as heck one assumes that one must use a surface grinder but how does one clamp a sphere?

    Cheers,
    Bob Welland

  2. #2
    Join Date
    Jun 2004
    Location
    Melbourne Australia
    Posts
    5,456
    Post Thanks / Like

    Post

    Bob.

    Its certainly going to be hard. I figure only grinding or E.D.M You could hold a ball with enough force to grind using a vee block and a tool makers vice. Surface or tool and cutter grinder. A small 3 jaw chuck would also do.

    I’m not buying the book, can you please elaborate on the method of using this ball. I can picture it. A sphere with a flat. Just not sure what you would use it for in a milling vice.

    As a side note. I recently picked up some roller elements out of an old large spherical roller bearing. Rollers about 1” x 1 ½” long. Ground them top and bottom. They make great buttons for use in a vice instead of parallels, where you are drilling close to the edge. Or for three point locations for inspection work on a plate.

    Regards Phil.

  3. #3
    Join Date
    Jun 2001
    Location
    downhill from Twain\'s study outside Elmira, NY
    Posts
    11,036
    Post Thanks / Like
    Likes (Given)
    4126
    Likes (Received)
    3854

    Post

    Collet. or 3 or 4 jaw chuck. I've done a few, though to drill and tap (after annealing); not specifically to flatten.

    smt

  4. #4
    Join Date
    Sep 2002
    Location
    Seattle, WA. USA
    Posts
    1,107
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    You use the ball bearing to establish a single point of contact on one side of a milling vice. You put the flat against one of the jaws and the round against the non-square material. This allows you to clamp a non-parallel block in the vice and have it sit flat against one face and still clamp. This seems like a somewhat better approach then using a cylinder, which is the more common practice.

    I was thinking that casting the ball in some way might work. The question is with what material and how do you get it off when you are done?

    Cheers,
    Bob Welland

  5. #5
    Join Date
    Nov 2002
    Location
    Kalispell,MT U.S.A.
    Posts
    51
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    Bob, Face both ends of a piece of round TGP stock or anything that is same diameter end for end. Center drill one end with at least a 3/4 dia center drill. Put some of that salve type flux sold for half and half solder ( lead/tin) in the center drilled pocket, torch it until that melts and tins the c-bore, flux the bearing ball and nest it in the now tinned pocket, re heat the stock until the solder is wet, and use a piece of real cotton cloth to roll the ball in the pocket enough top besure the ball is tinned, take another piece of bar and rest that on top of the ball to chill it. When the assembly is room temperature you can measure end for end with the Ht gage or a mike. Whatever you grind off the end of the ball reduces end length of the assembly, so if the dimension from the spherical radius to the flat is some kind of given, that's the easy way to measure it. When you are satisfied you have enough flat on the ball, re-heat to melt the solder. Set it on a chill bar to cool. Remove solder with a wire wheel on the bench grinder. Small dia wire preferable. If you want all the solder off. you can put some supermarket lye and about a pint of water in a STEEL pan , and boil the ball in this.Lye eats tin.Better to use a hot plate. SWMBO types don't like machine shop chemistry in the kitchen. Lye eats the tin but the remaining lead can be brushed off with an old tooth brush.. Use appropriate OSHA approved precautions, Lead and grinders are involved. If you know a gunsmith with an immersion bluing outfit,his blue bath will eat the remaining solder, too, and as a plus the flattened sphere will be a nice shiny black for contrast if you go that route.
    Tom Burgess

  6. #6
    Join Date
    Jul 2001
    Location
    Fullerton, CA USA
    Posts
    2,898
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    13

    Post

    I'd put the ball in the small vise and put it on the surface grinder. That will only work if you are grinding less than half the diameter though.

    Les

  7. #7
    Join Date
    Feb 2003
    Location
    Edmonton Alberta Canada
    Posts
    445
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    I usually use a 1/2" aluminum [round] about 2" long...it does do the same thing as the ball.
    The ball would be awkward to use, but you never know until you try.
    Putting on a flat on the ball....lathe, cut with ceramic insert, or grinding.
    But really, pushing with a ball against the workpies will cause markings, so really not a good idea.
    You could also take a 1" round bar, cut it about 3/4" long, face it on lathe to clean and turn one side, from the end about 1/8" and a diam.of about 3/8" ....in other words a 3/8 diam. step, which will give you also a small pressure point and less likely to mark your workpiece.
    Konrad

  8. #8
    Join Date
    Mar 2005
    Location
    Central WI - ~USA~
    Posts
    375
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    I use a short length of rod. Put the best looking surface of the stock against the fixed jaw and position the rod aginst the moving jaw. Take a light cut off two surfaces. Then rotate the part and finish it up!. Mr. Harvey's tip would be the ultimate way to do this, due to the single point of contact. But, it is overkill for most work. My Favorite Trick is to surface grind the part parrallel and machine from there!. Well, that's enough thinking for tonight!!

    Oh! I Forgot- to put the flat on the ball, clamp it in a grinding vise with a v-block and grind away -- later!!zzzzzzz...

  9. #9
    Join Date
    May 2004
    Location
    Chilliwack B.C. Canada
    Posts
    700
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    A hardened steel ball grinds easily on a regular grinding wheel. If you chuck a piece of round stock, drill a hole through it, then enlarge the hole partway for a press-fit of the ball, it can easily be ground flat using a tp grinder, or even a hand-held dremel tool. You might start by taking most of the metal off with a regular grinder, then chuck it in the lathe for the final grinding. You'll be able to see when you're getting a concave grind on the ball, and this is what you need when nearing the end of the grinding operation. Of course, take care to protect the lathe's ways from the grinding dust. After you're 'deep' enough into the ball, remove the holder from the chuck and punch the ball out with a rod through the through hole. Place some 220 to 400 grit sandpaper on a flat surface then place the ball on the paper and carefully skid it around without rolling it. You'll be polishing up the edge of the concave you ground, and that's it. No need to polish to a complete flat.
    Whether it's suitable for your application is up to you to decide.

  10. #10
    Join Date
    Dec 2002
    Location
    Granville,NY,USA
    Posts
    3,925
    Post Thanks / Like
    Likes (Given)
    316
    Likes (Received)
    417

    Post

    I would tend to simplify it and hold the ball with a pair of vise grips and head for the belt sander. A 60 grit belt will make a flat pretty quick. The hardest part will be deciding how to orient the ball to get the flat where you want it.
    I have several of these and they are handy. I would recomend using a fairly large ball. Something around .75" - 1". One draw back of the the ball bearing trick is that it will tend to put divots in you vise jaws. If possible I would find something softer than my jaws to use.
    I like a small brass plug similar to the bearing with a flat. I is easy to make. Just take a piece of 1 inch diameter brass and face one end then file a shallow convex surface on the other end. Keep your OAL under 1 inch. Of all the methods that I have seen this one works the best for me.

    Take care,

    ARB

  11. #11
    Join Date
    Mar 2005
    Location
    England
    Posts
    403
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    I've made dozens of these for gauging aeroparts (same idea, differant use) I have used wire EDM and Sinker EDM using a little jig to hold them but I also did some on a T&C grinder with this jig, I held the ball between two plates with a counersunk hole in each plate to make a kind of circular vee block, I then held this little assembly in a small precision vice (no glues or anything) with the ball held just a little over center, then i just ground the ball (2" dia) to 1.1250" high, grinding the jiging plates also
    Hope this helps

  12. #12
    Join Date
    Oct 2003
    Location
    NYC
    Posts
    269
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    I've read a tip (somewhere) recommending that the ball be secured in a vise between two circular recesses such as that provided by apprpriately sized hex nuts.

    I haven't tried this myself.

    Mike

  13. Likes SteveBausch liked this post
  14. #13
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    29,318
    Post Thanks / Like

    Post

    An amazing effort to go thru so you can mark up a workpiece with "brinnel" dents. Two chunks of Ash, Oak, Hard Maple or the like, appropriately differing in size and shape can hold most any odd shape in a vise. Easy to generate on belt sander, pitch in trash or "possibles" box when done.

    IMHO :rolleyes:

    John

  15. Likes SteveBausch liked this post
  16. #14
    Join Date
    Aug 2003
    Location
    Eureka, CA, USA
    Posts
    1,651
    Post Thanks / Like
    Likes (Given)
    353
    Likes (Received)
    263

    Post

    Mr. Noder's statement leaves little to add.

    But if you want to try the ball trick in your vice, you could improve on the concept. Grind one face of a small rectangular blank (pick the material to suit your application) and make a pocket on the opposite face of the blank with a ball end mill, same size as the ball you want to use.

    Place your flattened ball against the movable vice jaw and rest the ground plate against the workpiece, engaging the ball in the spherical pocket. The ball/socket joint allows angular movement with adequate surface area to prevent marring the workpiece.

    FWIW, a standard woodworking clamp works great for holding balls. Drill a small pilot hole completely through both jaws with the clamp closed. Disassemble the clamp and countersink the pilot holes on the inside of both jaws. Works great for modifying decorative wooden balls and the like. (Mine has held a number of cool gearshift knobs for modification.)

    After clamping the ball, the woodworking clamp may be laid flat on a drill press table, for example, and if need be, clamped to the table for security.

  17. #15
    Join Date
    Oct 2003
    Location
    East Peoria, IL, USA
    Posts
    5,377
    Post Thanks / Like
    Likes (Given)
    334
    Likes (Received)
    781

    Post

    find a piece of pipe and part it off and nest the ball in the ring and clamp it in the vice.

  18. #16
    Join Date
    Feb 2005
    Location
    Birmingham, AL
    Posts
    4,027
    Post Thanks / Like
    Likes (Given)
    13
    Likes (Received)
    49

    Post

    Nest ball in a flat washer. Weld. Your done.

  19. #17
    Join Date
    Sep 2002
    Location
    Seattle, WA. USA
    Posts
    1,107
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    If the ball is large and it is used on a face that you are going to mill anyway then why is a shallow divot any big deal? One might argue that you are going to harden the work at the point of contact but a large ball is going to spread the pressure over a circular area (Hertz deformation). Brinnel indenters are significantly smaller - the largest I've seen being 10mm - then what is suggested for this purpose - 3/4" or larger.

    Thanks for all of the pointers!

    Cheers,
    Bob Welland

  20. #18
    Join Date
    Aug 2003
    Location
    Eureka, CA, USA
    Posts
    1,651
    Post Thanks / Like
    Likes (Given)
    353
    Likes (Received)
    263

    Post

    Vises, clamps, fasteners, many other mechanisms, develop holding capability by friction. The magnitude of clamping is determined by the coefficient of friction (materials, surface finishes, lubrication), the load applied and the clamping area.

    A point contact, such as a sphere, has very small contact area and is not an ideal clamping device unless it indents the mating surface (at which point it is acting sort of like a shallow pinned joint rather than a clamp).

    An efficient clamping device has a large surface area relative to the applied load. This maximizes the friction and immobilizes the workpiece while minimizing stress/deformation on the workpiece from excessive loads.

    John Noder's suggestion of using scraps of hardwood was excellent - the wood slightly deforms to the shape of the workpiece, filling in tiny irregularities, accomodating angular differences and hugely increasing the friction in the workholding structure. It's pretty much an ideal clamping device.

    However your point regarding machining the surface that is indented is certainly valid. It all depends on the application, right ?

  21. #19
    Join Date
    Sep 2002
    Location
    Seattle, WA. USA
    Posts
    1,107
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    Yes - nice description!

    Cheers,
    Bob Welland

  22. #20
    Join Date
    Jan 2004
    Location
    New Ulm, Minnesota, USA
    Posts
    131
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    Or you could try a hydraulic vise jaw that will grab irregular objects. Here is a link to one patent: http://uspto.gov/ Search for Patent 6,345,816 then if you click on "Images" you can view a drawing.


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
  •