Interpolated bore circularity - Page 3
Close
Login to Your Account
Page 3 of 3 FirstFirst 123
Results 41 to 45 of 45
  1. #41
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Florida
    Posts
    3,221
    Post Thanks / Like
    Likes (Given)
    1437
    Likes (Received)
    1514

    Default

    Quote Originally Posted by Ox View Post
    We actually got in trouble once for this - likely from an inspector that didn't know much...

    I made some cyl rod ends that had a cross hole for an oil-lite bushing. I interped in my Y axis lathe, and my 3 pt mic loved the results.
    BUT - I did leave a witness exit mark, but the mic's didn't care about it - so why should I?

    Well, the inspector didn't like that witness mark, so (as I recall - it was >15 yrs ago) my wife drove up to Saginaw and maybe 100%'d that feature, or ???
    I just don't recall the outcome on that anymore.

    BUT - when I say about the insp maybe not knowing quite all they should have - a cpl yrs prior, from this same customer, I got a written warning (but accepted parts) for a similar but smaller sister part that was small enough to just ream the hole - that the flats on the tang "didn't look like the rest of the part, but were still within S/F spec, but "watch it"".

    Well no Shiite! It's a milled feature on an otherwise turned part!

    I s'pose that I could have used an exit rad, or maybe larger rad (I don't recall) to mitigate the exit witness mark on the interped hole, but I just didn't see the need as it was to spec, but cosmetics seem to trump the gauge sometimes....


    ----------------------

    Think Snow Eh!
    Ox
    My number one gripe at current job!! We do some redonculous BS to make it pretty. I am not talking having a nice looking part (I totally get and stand behind that), I am talking "welll I can see this little line here" Ya I know, it is a cutting tool, it makes marks when it cuts the material away!

  2. #42
    Join Date
    Jun 2013
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    46
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    10

    Default

    Well if you want pretty google Steve Earle
    Fraser Action
    Lots of care and hand polish ....$$$$

    I might have it all wrong but the part seems to be made for a C axis or for a lathe.
    Just my tuppence.

  3. #43
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    160
    Post Thanks / Like
    Likes (Given)
    27
    Likes (Received)
    51

    Default

    So this is what i did.
    I used a 4" face mill using APTK inserts and a boring toolpath with a .02 pitch and 10in/min. (Remember that the bore is 4.25" OD and 1" deep.) (I might have used a little different numbers earlier in explaining the sizes) It worked well (imo). The surface finish was really excellent. Better than I'm used to with a typical side cut via 1/2" EM. ANd way better than the crap I was getting with he boring head. The concentricity error went from 1.5-1.75 thou down to .5 thou. (I admit I don't recall the exact numbers from before when I interpolated, just that it was more that 1 thou by a decent amount.) That made it much easier to stay in the diameter tolerance. I was slighly surprised that more of the error did not go away, but as others suggested there is some types of machine error that the smaller toolpaths would cancel out and some it would not.

    All in all it went well. I did think later about some programing tricks like the quadrant hack or breaking it into a thousand arcs. In hind sight I would have tried breaking the circle into 4 arcs so that the controller would hit each endpoint. Or maybe used a boring routine. But this worked and the bores are right.
    I did break out my dial bore gauge to get better numbers. Its a cheap brand but was easier to use than the snap gages. Still the snap gages were really good side by side with the bore gauge.

    Thanks to everyone for the input.

  4. Likes cameraman liked this post
  5. #44
    Join Date
    Sep 2011
    Location
    Laurel, MD
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default

    Some interesting suggestions, don't know if it's been mentioned (I didn't read thru all the posts), but when I have a close tol. dia, I Climb, Spring, then Conventional Cut. Reversing the cut seems to help the Back Lash Comp. to work better. This is assuming the Back Lash Comp. 1) is set properly, and 2) is up to date.

    JM2C
    Bill

  6. Likes Larry Dickman liked this post
  7. #45
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    160
    Post Thanks / Like
    Likes (Given)
    27
    Likes (Received)
    51

    Default

    Reversing the direction is a really interesting idea. I will keep that in mind for later. Thanks


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
  •