taper attachment
Close
Login to Your Account
Likes Likes:  0
Results 1 to 8 of 8
  1. #1
    Join Date
    Sep 2007
    Location
    delaware
    Posts
    188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Default taper attachment

    I have a turn-nado 17" lathe that for years I've been machining tapers and all of a sudden on smaller shafts I started to get a spiral cut at the end of the taper. It did not seem like chatter and I noticed that the taper attachment seem to bind a bit the closer it got up the taper toward the chuck so I loosened the 3 set screws on the gib on the slide block. That took the spiral cuts out but it caused the taper to be longer in length. I took a known good taper on a large shaft that is 6.5" long set it up in the chuck placed a dial indicator on centerline of the taper, engaged the taper and manually ran the saddle up the taper to reset the angle of the taper attachment. I got to a point where I get 0 on the indicator for 4.5" and then the indicator says the cross slide was moving away from the part which explained the spiral cuts I was getting. So any ideas as to what is wrong or warn out?

  2. #2
    Join Date
    Sep 2010
    Location
    moscow,ohio
    Posts
    5,952
    Post Thanks / Like
    Likes (Given)
    580
    Likes (Received)
    1901

    Default

    Just a guess but...cosine error....as the taper gets smaller wear is exagerrated exponentially as the tool deviate from centerline.

    Betting it is as you get closer to the headstock???

  3. #3
    Join Date
    Sep 2014
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    808
    Post Thanks / Like
    Likes (Given)
    574
    Likes (Received)
    267

    Default

    Sounds like wear in the taper attachment dovetail ways?

  4. #4
    Join Date
    Sep 2007
    Location
    delaware
    Posts
    188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Default

    Well yes it happens closer to the chuck and I am going to take the attachment apart today and check for wear thanks to both of you for input. I have bought parts from latheman on this forum before is he still around?
    Thanks again I'll post what I find later today.

  5. #5
    Join Date
    Sep 2007
    Location
    delaware
    Posts
    188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Default

    OK,I've taken the attachment apart and cleaned at least 20 years of smeg off and I find the (according to the manual) swivel bar key to be about .004 worn in the center part of the slide and of course the end that is closest to the headstock is not worn. I have no idea what tolerances are so I'm not sure if I should put it all back together or replace the part which as this part has the unit number on it is probably not available unless one purchases the entire unit. Anyone have any ideas and a source for parts?
    Thanks

  6. #6
    Join Date
    Sep 2014
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    808
    Post Thanks / Like
    Likes (Given)
    574
    Likes (Received)
    267

    Default

    Quote Originally Posted by propman View Post
    OK,I've taken the attachment apart and cleaned at least 20 years of smeg off and I find the (according to the manual) swivel bar key to be about .004 worn in the center part of the slide and of course the end that is closest to the headstock is not worn. I have no idea what tolerances are so I'm not sure if I should put it all back together or replace the part which as this part has the unit number on it is probably not available unless one purchases the entire unit. Anyone have any ideas and a source for parts?
    Thanks
    Ted is still around: [email protected]

    The usual process would be scrape the dovetails so they're straight again. I've only just begun the scraping journey so I'm no help, but there are people on this forum who are experts at it and could get it factory-new again in short order for a reasonable fee. Probably cheaper than trying to find parts from another Turnado which will also be worn.

    Maybe you'll get lucky and Ted has some NOS parts on the shelf.

    Best of luck!

  7. #7
    Join Date
    Sep 2007
    Location
    delaware
    Posts
    188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Default

    Thanks tom but there are no dovetails except for where the base unit slides into the bracket that holds the hole attachment to the lathe and that doesn't really matter as far as I see and once it is put into the base it doesn't move. All the other ways are straight like box ways with straight gibs. the bar that sets the angle to be cut is straight sided and fits into a straight sided block that has a straight gib to take up any play and that block attaches to the CS. So I may just try to use a flat surface to lightly sand the bar that sets the angle to be cut and see if I can get the .004 wear out and see if that works and thanks for passing on the contact for latheman!!

  8. #8
    Join Date
    Sep 2014
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    808
    Post Thanks / Like
    Likes (Given)
    574
    Likes (Received)
    267

    Default

    Quote Originally Posted by propman View Post
    All the other ways are straight like box ways with straight gibs.
    OK, just shows my unfamiliarity with the later SBL models. My war-era 16" has dovetailed ways on the TA.

    Regardless, the process is the same for both...scraping. Your approach of sanding on a flat/square surface may work. It may also introduce a taper into the straight/box ways, albeit with straight sidewalls, and you're no better off than before. The trick will be precise measurements as you proceed. A couple thousandths of an inch of taper on a two relative sliding surfaces might as well be a mile. At some point in its travel it will bind up when the clearance goes to zero.

    Tom


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
  •