Announcement

Collapse
No announcement yet.

Possible to make a qctp "indexing?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Possible to make a qctp "indexing?

    I'm curious if it is possible, or practical, to somehow make a qctp index? I thought I remembered reading something about this but it now escapes me. I'm thinking that having a swivel compound will make an indexable qctp moot?
    Thanks

  • #2
    Dorian makes an indexing toolpost that can take four holders. The “Quadra”

    Comment


    • #3
      IIRC, the Multifix has 40 positions?

      http://www.lathes.co.uk/multifix/

      Comment


      • #4
        The QCTP on my lathe has radial grooves in the bottom and the compound where it mounts is drilled for a spring plunger. The face of the plunger has a taper so the toolpost can be rotated forward to the next slot but is prevented from rotating the other way in response to cutting forces.
        .
        "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

        Comment


        • #5
          Drehblitz, Multifix. Bring the big cheque book. They are quite repeatable so handy if making a run of something....so for me or others rarely doing a run there's not a huge benefit.

          in Toronto Ontario - where are you?

          Comment


          • #6
            Could drill a hole in the bottom for a spring and ball, then fix a plate under it for detents.

            Three ball plungers and 24 detent holes would make 5 degree divisions.

            Comment


            • #7
              What need does an indexing toolpost satisfy?

              -D
              DZER

              Comment


              • #8
                I'm thinking that indexing on it's own isn't a guarantee of consistent tool point placement. Consider how many tool posts are held by a plate in the cross slide T slot. So they are free to slide. So any indexing modification would need to start with a secure center post mount.

                Next is the play that we get between the body and the post. Alll the posts I've seen have at least SOME float to them. To get a consistent indexing position for repeatable production work you would need some way to locate the main body's center rotation with some manner of collet style action that not only presses against the body to pull it to the center position but at the same time closes out any play to the center post. to me that sounds like a collet style clamping "washer" under the hold down nut.

                Once you have the post's body able to consistently center when tightened the actual indexing issue get's pretty simple really. Just a matter of how many stops you want in it and figure out a suitable ratchet setup. Or if you want a manually retracted index pin so you can rotate either way and avoid going around the clock each time.

                But if the best reason I know of for this feature is doing small batches of repetitive cuts then do we need to index the head or do we simply need to make up tool holders that hold the cutters at the required positions? If you can buy or make all your tool holders and buy the insert tool shanks that hold the inserts in the required position when sitting at 90 or inline with the lathe axis then your "indexing" could be all in the holders.

                And if you can make some of your own holders this allows you to machine in some odd angles now and then if needed. And perhaps one "holder" with a reference face that you use for zeroing in the main body much like zeroing the jaw of a mill vise.

                With this you're not a slave to the index points as you alter the compound. You just switch the compound as required for threading or cutting a taper or to move the cutting tip to allow for working with tail stock centers or other needs then either stick the reference holder's face up against the work or against the chuck jaws or dial it in as needed for the work being done. Or for some jobs just don't dial it in.

                But when you need to make a batch of things that need a lot of tool changes you can trust that the holders for all the main function cutters are consistent. So from roughing to finish to threading to chamfering and finally parting the holders are all set to work with the same body position.

                If you can do this would you still need indexing ability?
                Chilliwack BC, Canada

                Comment


                • #9
                  I believe the good old McCrosky four way indexing posts used a curvic coupling. Think the Quadra does as well.

                  Comment


                  • #10
                    Originally posted by Doozer View Post
                    What need does an indexing toolpost satisfy?

                    -D
                    I use it a lot on my 4 way, load 4 tools, cand do 4 pops in a row, and accurate.
                    on my turret lathe, you had and indexing 4 way, plus a back tool.. so 5 tools , or 4 and cutoff..

                    Comment


                    • #11
                      Originally posted by 754 View Post

                      I use it a lot on my 4 way, load 4 tools, cand do 4 pops in a row, and accurate.
                      on my turret lathe, you had and indexing 4 way, plus a back tool.. so 5 tools , or 4 and cutoff..
                      Sounds like you want the Dorian Quadradex then.

                      -D
                      DZER

                      Comment


                      • #12
                        Was gonna point out, most if not all 4-way tool posts *are* indexing. Usually a bottom washer with ball detents every 45 degrees.
                        25 miles north of Buffalo NY, USA

                        Comment


                        • #13
                          I guess my lathe is nicer than I thought, it came with 4 way indexable, accurate enough to make a lot of parts to sell.
                          I see on here, a lot are used to mediocre tooling and make excuses for it.
                          in a post by BcRider lists all the things you can do to not have one, but it involves toolholders...... all that instead of just indexing.
                          I had my South Bend setup beginning of 2019, had a new part to put in production, has cash tied up in laser cut parts and needed some turned parts. Without a 4 way post and grads on the carriage hand wheel, it became such a frustrating experience, I walked away from it, gave up..

                          Comment


                          • #14
                            Originally posted by Doozer View Post

                            Sounds like you want the Dorian Quadradex then.

                            -D
                            Sounds like more people could use an accurate 4 way.. than my need for a Dorian QC..

                            Comment


                            • #15
                              Originally posted by 754 View Post
                              I guess my lathe is nicer than I thought, it came with 4 way indexable, accurate enough to make a lot of parts to sell.
                              I see on here, a lot are used to mediocre tooling and make excuses for it.
                              in a post by BcRider lists all the things you can do to not have one, but it involves toolholders...... all that instead of just indexing.
                              I had my South Bend setup beginning of 2019, had a new part to put in production, has cash tied up in laser cut parts and needed some turned parts. Without a 4 way post and grads on the carriage hand wheel, it became such a frustrating experience, I walked away from it, gave up..
                              I loved my 4-way indexable when I had it, but the problem I had with it is, getting all the tools on the same center height. I absolutely am NOT going to shim anything, I believe shims are a poor hack.
                              25 miles north of Buffalo NY, USA

                              Comment

                              Working...
                              X