HBM Facing chuck. How does it work?
Close
Login to Your Account
Results 1 to 10 of 10
  1. #1
    Join Date
    Mar 2011
    Location
    Essex, UK
    Posts
    33
    Post Thanks / Like
    Likes (Given)
    3
    Likes (Received)
    22

    Default HBM Facing chuck. How does it work?

    My dad has had a little Kearns S-type Horizontal Boring Machine for pretty much as long as I can remember (so call it 50 years)

    It is the facing-chuck model. You can twirl a handle at the back and the radial position of the tool slide changes. (And there is a power-feed for this axis too).

    I have never quite worked out the mechanism that achieves this motion. Has anyone ever seen a picture or diagram?

    It isn't the same as the stroke adjust on a shaper, as on a shaper the adjusting handle rotates when the machine is operating. On the Kearns the adjusting wheel is stationary except when the radius is being adjusted.

  2. #2
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    30,697
    Post Thanks / Like

    Default

    Here is what it does

    the facing
    Or in your neck of the woods, you might say surfacing

  3. #3
    Join Date
    Sep 2006
    Location
    SW Wisconsin
    Posts
    553
    Post Thanks / Like
    Likes (Given)
    37
    Likes (Received)
    143

    Default

    Hey Andy. Most facing head types have a finger that trips or turns the adjuster at each revolution of the head to get the radial feed.

    Are you the same Andy from the Linuxcnc list?

    Ed.

  4. #4
    Join Date
    Oct 2009
    Location
    Louisville, KY, USA
    Posts
    984
    Post Thanks / Like
    Likes (Given)
    214
    Likes (Received)
    219

    Default

    ...and the same Andy from the Neracar group?

    Small world. :-D

  5. #5
    Join Date
    Feb 2007
    Location
    Aberdeen, UK
    Posts
    3,821
    Post Thanks / Like
    Likes (Given)
    1340
    Likes (Received)
    1532

    Default


  6. #6
    Join Date
    Aug 2009
    Country
    AUSTRALIA
    Posts
    529
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    72

    Default

    That is the second diagram of a facing head I have studied but both appear to operate the same. The important part as I see it is the differential. The drive comes off the spindle, to the differential, which drives the facing feed shaft on the spindle at the same rate, but as it rotating also it has no effect but to cancel it all out. However when you rotate the differential itself relative to it all, it has the effect of advancing or retracting the drive to the facing head at what ever rate is set by the feed gears. That facing slide is driven by a feed screw where as the ones I have used had a worm driving a rack on the slide.

  7. #7
    Join Date
    Oct 2009
    Location
    Oregon
    Posts
    4,744
    Post Thanks / Like
    Likes (Given)
    5128
    Likes (Received)
    2443

    Default

    The facing head for my 4" Kuraki uses a special 50 taper holder installed in the quill. That holder has a rack on it that runs a gear inside the facing head. You can hand feed or power feed the slide using the quill feed. Just have to be careful not to push the quill through the front of the facing head (there's a sheetmetal cover there)

  8. #8
    Join Date
    Mar 2011
    Location
    Essex, UK
    Posts
    33
    Post Thanks / Like
    Likes (Given)
    3
    Likes (Received)
    22

    Default

    Thanks for the picture.
    (And sorry, all, for asking the same question again, but I am sure I could not find this thread when I looked a couple of days ago)
    I think I might need to experiment with Meccano or something, I am not really seeing the details of what is keyed to what in the differential area.
    But I suspect that the back bevel spins at twice the speed of the carrier, and the control shaft rotates the front bevel?

  9. #9
    Join Date
    Aug 2009
    Country
    AUSTRALIA
    Posts
    529
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    72

    Default

    Quote Originally Posted by andypugh View Post
    Thanks for the picture.
    (And sorry, all, for asking the same question again, but I am sure I could not find this thread when I looked a couple of days ago)
    I think I might need to experiment with Meccano or something, I am not really seeing the details of what is keyed to what in the differential area.
    But I suspect that the back bevel spins at twice the speed of the carrier, and the control shaft rotates the front bevel?
    The front or right hand bevel is keyed to the feed shaft, and in normal no feed conditions will be stationary, the left hand bevel drives all the time. When feeding the right hand bevel will turn advancing the the drives’ position so the feed shaft in the spindle advances also.

  10. #10
    Join Date
    Aug 2009
    Country
    AUSTRALIA
    Posts
    529
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    72

    Default

    It’s an interesting spindle design and a little backwards to how you would expect. I recall Tyrone Shoelaces speaking of a Kearns borer which had unusual thermal growth of the spindle, which seeing how the left hand end is fixed by angular contact ball bearings and the right hand cylindrical bearings I can see why. Usually they would be the other way around, or both at the front and another set of cylindrical rollers at the back, in my limited experience with spindles.


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
  •