Help with OD/ID grinder. Chattering/ help with speeds and feeds????!!! - Page 2
Close
Login to Your Account
Page 2 of 2 FirstFirst 12
Results 21 to 32 of 32
  1. #21
    Join Date
    Apr 2018
    Country
    UNITED STATES MINOR OUTLYING ISLANDS
    Posts
    4,151
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1874

    Default

    Quote Originally Posted by fettersp View Post
    do you use aluminum oxide on hardened tool steel?
    You most certainly can. I've ground thousands of bores 8620 carburized to 61-63 Rc with aluminum oxide.

    In fact, Mr Milland would like you to use Borazon but especially at first I would not recommend it. In a way it's easier because cbn will cut like a mofo almost no matter what (do NOT touch the wheel - unlike a nice normal grinding wheel that just smooths the skin, a borazon wheel will rip you to shreds just by getting near it.) But they cost a lot more and they are harder to get running true and you don't get a good feel for what the grinder is doing with them. And the finish isn't as good.

    You could be running this job for fifty bucks with aluminum oxide, getting the corect cbn wheel is going to run $300 .... and the alox wheels are going to be a lot more forgiving if you whoops.

    One other thing, since you said you are a beginner at grinding - DO NOT STAND IN FRONT OF THE WHEEL when you turn on the spindle. Step aside a foot or two so if the wheel blows up, it goes past you instead of putting a hole in your forehead. Starting is usually when grinding wheels explode.

  2. Likes michiganbuck liked this post
  3. #22
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    9,210
    Post Thanks / Like
    Likes (Given)
    2186
    Likes (Received)
    6381

    Default

    Quote Originally Posted by EmanuelGoldstein View Post
    In fact, Mr Milland would like you to use Borazon but especially at first I would not recommend it.
    I'd only recommend it when bought from my new store, "Honest Milland's House of Pizza and CBN Wheels". It's part of a new franchise I'm launching.

  4. #23
    Join Date
    Mar 2005
    Location
    Kansas
    Posts
    7,894
    Post Thanks / Like
    Likes (Given)
    486
    Likes (Received)
    3757

    Default

    fettersp, you seem to be out of your comfort zone. You are making us guess about what you are doing and where your problem lies. Its like the parable about the blind men describing the elephant. Give us a couple of pictures, give us all the necessary information, and you will get better suggestions.

  5. Likes michiganbuck liked this post
  6. #24
    Join Date
    Apr 2020
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    32
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    1

    Default

    Ok so I just found out why the wheel was untrue in the first place. I set this job up on Thursday and was getting .0005 smooth passes. Turns out my brother wanted to help by grinding the little arm that switches the direction of the table and it crashed the machine and made the wheel have a big high spot on Thursday night without telling me. I remade the little arm and its switches smooth again but the wheel is still untrue. My main issue is trying to get this wheel true again(resin diamond). About an hour ago I spent around 20 minutes using a carbonium stick and an aluminum dressing stick on it by hand. currently it is a smooth transition within .001 inches instead of having a huge high spike in one spot.

    Yes I am out of my comfort zone with grinding but I have to learn since a lot of our jobs need hardturned or ground.
    I did also find a tiny piece of metal that the screw was laying on making the wheel slightly lopsided(I think). I don't know if this would be an issue.

    But the main things I would need help with is How to true a wheel if Im not able to just indicate within the .0005 like I normally do, What types of wheels work best with what material( I leave about .008 extra on diameter to finish grind to get the part to tolerance and mostly grind hardened O1, H-13, 4140,A2), What speeds should the head rpm and the table feed be, How much can I take off at one time?(I normally only take .0005 a pass)

  7. #25
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    9,210
    Post Thanks / Like
    Likes (Given)
    2186
    Likes (Received)
    6381

    Default

    So this whole bit of "diamond bad with steel" is running off your back like water off a duck?

    I'm out.

  8. #26
    Join Date
    Apr 2020
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    32
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    1

    Default

    So I just went back to the shop and looked up the wheels. There vitrified CBN and the manufactures website says these are used for tool and die steels?
    are these acceptable or is aluminum oxide pretty much the only option? I was able to true the wheel to .0005 but have not tried grinding on it yet.

  9. #27
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    11,621
    Post Thanks / Like
    Likes (Given)
    3968
    Likes (Received)
    4132

    Default

    QT [if anyone could point me in the direction of some good books to learn about grinding would be helpful]

    http://www.abrasiveengineering.com/bkgrdwhltoc.pdf

    https://www.amazon.com/Handbook-Mach...3305594&sr=8-1

    Chapter 5: Surface Grinder – Manufacturing Processes 4-5

    How to run a lathe and many lathe operation books give great lathe advice. The Cincinnati TC grinder manual and many other TC grinder manuals give great advice on TC grinder use…
    I have read many books on grinding and have yet to find a surface grinding book that gives surface grinding techniques…I think such a book does not exist.

  10. #28
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    9,210
    Post Thanks / Like
    Likes (Given)
    2186
    Likes (Received)
    6381

    Default

    Quote Originally Posted by fettersp View Post
    So I just went back to the shop and looked up the wheels. There vitrified CBN and the manufactures website says these are used for tool and die steels?
    are these acceptable or is aluminum oxide pretty much the only option? I was able to true the wheel to .0005 but have not tried grinding on it yet.
    If they're CBN and the workpiece is hard steel, and you've got good coolant lubricity and flow, they should work assuming they're not really fine or coarse grain. Like EG says, the finish may not be great (at least until they've been used a while), but they should do the job.

  11. Likes michiganbuck liked this post
  12. #29
    Join Date
    Apr 2020
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    32
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    1

    Default

    Ok thats good news. The OD doesn't need to be a super fine but the ID Does. Would you use aluminum oxide wheels to get a good finish or would I be better off grinding to size and lapping with diamond compound/polisher?

  13. #30
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    11,621
    Post Thanks / Like
    Likes (Given)
    3968
    Likes (Received)
    4132

    Default

    Quote Originally Posted by fettersp View Post
    Ok thats good news. The OD doesn't need to be a super fine but the ID Does. Would you use aluminum oxide wheels to get a good finish or would I be better off grinding to size and lapping with diamond compound/polisher?
    Needing .002 to .0005 Id is easy. Needing .0002 is more difficult. Fifty millionths and you need very close measuring tools.12 millionths and better you should send it to a decent grinding shop.

    For id choose a target below your needed size (smaller) to see if you can make tolerance of surface finish and size in a safe area. If so, then go on to your actual needed size.

    YouTube

  14. #31
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    11,621
    Post Thanks / Like
    Likes (Given)
    3968
    Likes (Received)
    4132

    Default

    Grinding a through bore a 60 grit perhaps an I to K hardness wheel will give a very nice surface finish, A white AO is the lower price wheel, and blue, pink, brown and salt & pepper AO will give differences mostly for special situation or production work where chasing wheels can offer a little advantage. Ceramic wheels are good but very expensive so their use should be with as needed not the always norm for every job.
    Grinding a bore to an inside corner you may need to use two different wheels, one to grind size and depth, and a finer grit perhaps harder wheel to reduce the inside corner radius and it only grinding the inside corner,
    The grind path for a dead end or inside shoulder step often is to infeed small increments inside the bore and travel out, with frequent dressing to avoid a tapering bore that is big at the entrance of the bore

    When you are close to size often a one, two, and three finger push to the wheel head, or to the work holding fixture can give a little sparking so to take a very small amount of stock. Often less than a dial infeed. this is the way you might take .00005 or so from a part with less worry about taking too much.
    Last edited by michiganbuck; 06-28-2020 at 04:45 PM.

  15. Likes eKretz liked this post
  16. #32
    Join Date
    Jan 2018
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    11
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Truing a wheel and dressing a wheel are two separate operations. With CBN wheels you MUST indicate the wheel within .0005 or better
    then use a brake truing device to true it up. Once it's true you can dress it with a stick when it loads up. A wheel that is not trued or balanced will not produce good parts.

    Are you using the swing down I.D. attachment to grind O.D?


Tags for this Thread

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
  •