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Cutting oil grooves in a bush.

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  • Cutting oil grooves in a bush.

    How is this done. .He doesnt show the mechanism behind this.
    https://www.youtube.com/watch?v=IW1tWxW1OYk

  • #2
    He is cutting a rh “ thread” in the infeed and a lh thread on the outfeed. How far past the inside edge of the bushing the tool travels before reversing determines their relative position,

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    • #3
      Can be done just like threading. With that speed of advance,("thread pitch") it may be tough on the gearing, but it is do-able.

      With a large lathe, having a coarse threaded leadscrew, it is less of a "gear-up" ratio, and maybe less tough on the gearing.

      Reversing feed without losing index is nice. The machine must have that capability.
      2730

      Keep eye on ball.
      Hashim Khan

      Everything not impossible is compulsory

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      • #4
        There would be some manner of outboard cam or rocker arm that is likely driven off a custom made lead screw or feed bar extension on the tail of the bed. At a few places in the video we can see the bearing end of the connecting rod between the compound slide body and the one cycle per revolution at the tail stock.

        If driven by the threading lead screw the quick change box or gearing would be set for 1:1 so every turn of the work gives a cycle of the cam or other linkage at the tail end of the bed and then through the connecting rod to the... .OK, wait, the lead screw would need to be running at 2:1 to get the figure of 8 and the cross over. 1:1 would give us an angled single oval.

        Same idea though. Lead or feed screw that is timed with the main shaft and chuck so it cuts this shape in tune with each revolution.
        Chilliwack BC, Canada

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        • #5
          Could just use a coarse thread pitch and pull the chuck around by hand. I have seen guys do that with a ball-shaped bit in the die grinder, in the tool post.
          25 miles north of Buffalo NY, USA

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          • #6
            I've seen a couple on YT that use a chain or wire on a cam, pretty neat tool though I can't for the life of me remember the names of the videos

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            • #7
              We used to do it manually with a large nose radius tool in a boring bar. Set a hard stop at the headstock end and clamp the tailstock as a stop at the other end, placed so the tool doesn't break out at either end. At low rpm, plunge the tool in at the tailstock end, manually feed the carriage rapidly to the headstock stop, allow to dwell then reverse feed to the tailstock. Not perfect, not beautiful, but functional.
              It's all mind over matter.
              If you don't mind, it don't matter.

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              • #8
                They feed the carriage in and out with a wobble plate (More or less) that is driven by the lead screw or feed shaft.
                Go here to see more of the carriage feed ( but not all unfortunately )
                Go to 4:40 (only) on this video
                https://www.youtube.com/watch?v=4FA0gRH93Zw

                I said wobble plate which gives a "Loop" type of groove, Because they have a oil ring groove at each end, they use a box cam
                The Cam (Follower) would drive a lever arm and the lever arm would have an adjustable stud for stroke variation settings so the stroke could be set
                for what ever "depth" needed.

                We had a 48 " American lathe that we put a clamped on sprocket on the back of the chuck and that had a chain driving a jack Shaft that ran full length at the back of the Lathe where you would have a taper attachment.
                The shaft was keyed and had a traveling sprocket that followed the carriage. By running a second chain from that sprocket to the carriage and tool slide, we could replicate any and all threads or grooves with chain/sprocket ratios ( AND not load the normal lead screw )
                Rich

                Edit
                We drove the tool slide which was parallel to the spindle , NOT the whole carriage as seen in the video .
                Last edited by Rich Carlstedt; Yesterday, 12:41 AM.
                Green Bay, WI

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                • #9
                  Originally posted by mattthemuppet View Post
                  I've seen a couple on YT that use a chain or wire on a cam, pretty neat tool though I can't for the life of me remember the names of the videos
                  this one appeared on the right hand side 'suggested' list with the OP's link. Quite clever imo...but I really don't want another thing on the todo list. I'd probably attempt an electronic coupling before I start buying (or roughly making) bevel gears. encoder signal from the spindle driving a stepper driven boring bar sled mounted on some cheapo linear rails.

                  https://www.youtube.com/watch?v=TJH2q5ylJXM
                  in Toronto Ontario - where are you?

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                  • #10
                    My new Pratt & Whitney lathe will cut 1 thread per inch.
                    Was thinking that would be useful for oil grooving.
                    Especially if you maybe cut 1 right hand and 1 left hand.
                    Thinking an oval inside a cylinder kind of affair.
                    Need to try it now, Ha !

                    -D
                    DZER

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                    • #11
                      Originally posted by Mcgyver View Post

                      this one appeared on the right hand side 'suggested' list with the OP's link. Quite clever imo...but I really don't want another thing on the todo list. I'd probably attempt an electronic coupling before I start buying (or roughly making) bevel gears. encoder signal from the spindle driving a stepper driven boring bar sled mounted on some cheapo linear rails.

                      https://www.youtube.com/watch?v=TJH2q5ylJXM
                      that's the exact one I was thinking of

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                      • #12
                        Originally posted by Mcgyver View Post
                        ................................ I'd probably attempt an electronic coupling before I start buying (or roughly making) bevel gears. ............................
                        Making bevel gears is not that horrible. Especially gears of that sort, where one gear is large, and the system is not close tolerance so will not suffer much from having form-cut gears. It looks like both have (or can have) tooth length a small percentage of the pitch cone length.
                        2730

                        Keep eye on ball.
                        Hashim Khan

                        Everything not impossible is compulsory

                        Comment


                        • #13
                          Obviously for a many part run you want power feed.. but when our shop did maintenance bushings that were one or two off, we used a simple manual method.
                          First, it's just a oil passage, so the grooves cross-section and variability is not critical. It's just to disperse the oil !
                          Also, putting a 360 oil groove near the ends was a no-no, so we did simple loops with an air grinder and a Ball Burr

                          The machinist marked the outside of the bushing with a magic marker to the desired pattern and then fastened a wand on the grinders side that ended at the Burrs center.
                          He would introduce the Grinder bit into the bushing . turn it on and match the wand end to the marker line and then cross-slide move to groove depth
                          and turn the chuck by hand one revolution while following the wand and marks with the carriage wheel .
                          You can make ovals or X's or a straight line very fast
                          The usual starting point was at the oil hole

                          Rich
                          Green Bay, WI

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