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_ Bored out my spindle tube while it was still in the machine: 2"dia 12" long (vid).

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  • _ Bored out my spindle tube while it was still in the machine: 2"dia 12" long (vid).

    When i bought the PM1440 lathe it was said to have a 2" spindle bore, well... it was close, 1.99x but just too small to slide a piece of 2" stock through it.

    A while back i seen a Keith Fenner clip, Super Shaker, where he used a line boring process which was pretty clever. After seeing his clip it seamed like a process which could be modified alittle to fit my needs.

    Took about .02 off the ID (.01 off the wall thickness) time will only tell if it was a mistake or not.
    2" stock now fits in there fine.

    Note: i use the term "line boring" loosely, not sure what to call this boring process.

    Heres a 10min video:
    https://www.youtube.com/watch?v=WoSrugyFKFU

    A link with alittle more info:
    http://site.thisisjusthowidoit.com/node/89


    _
    Last edited by iMisspell; 05-26-2014, 04:40 AM.
    ~ What was once an Opinion, became a Fact, to be later proven Wrong ~
    http://site.thisisjusthowidoit.com
    https://www.youtube.com/user/thisisjusthowidoit

  • #2
    I see lathe bore sizes advertised often just under a common dimmension.
    Ok, make the darned thing a few thou over , not to hard to figure out.

    Comment


    • #3
      50mm = 1.96". Looks like the spindle was bored to 50mm. Depending on the stock you need to put through it, you may need a little more off.

      How will this affect the taper?
      Last edited by Tony Ennis; 05-26-2014, 09:26 AM.

      Comment


      • #4
        That is a sort of line boring operation for sure Nice application, just proves that lathes are the most versatile tools ever invented
        Amount of experience is in direct proportion to the value of broken equipment.

        Comment


        • #5
          Could this application be used on a tailstock.If one wanted to rebore a tailstock for the quill. If one set the tailstock between the carriage and bolted it down and used a sliding p bronze bush in chuck and then just advanced the carriage .Damn I am not thinking straight.I need to give this one some more thought.
          You are a brave man to do that on such a newish machine.Clever approach though

          Comment


          • #6
            Maybe I missed it, but I don't remember seeing a shot of the finished bore.
            Location: Long Island, N.Y.

            Comment


            • #7
              Thanks for the interest guys.

              Dont have any long bar stock bigger then 2" dia (1.998), so i slapped some weld on it, turned it down and to 2.011 and fits snug. Im happy with it and dont want to push my luck and go any bigger. 2" cold rolled fits fine which is what i was after.

              Originally posted by Tony Ennis View Post
              How will this affect the taper?
              It shouldnt, i only took off around .02 (.03 tops) from the ID (maybe it was an oddball size spindle tube). Next time i yank off the chuck, and if i remember, ill check it out.

              Originally posted by plunger View Post
              Could this application be used on a tailstock....
              You are a brave man to do that on such a newish machine
              Maybe, the only thing i would worrie about is the carriage wandering alittle in the X (depending on how sloppy/worn the machine is), if you could lock the X, then i dont see why it wouldnt. Since i was using two bushings and it was a nice fit, i was not concerned about it. Im glad you brought that up, a new tail stock with a lever to make drill pecking easer is on my todo... when i decided i wanted ot make a new tail stock, boring it out was a concerned, i hope your on to something

              As for being brave, my cheeks where clamped shut like a virgin in prison.

              Originally posted by RichR View Post
              Maybe I missed it, but I don't remember seeing a shot of the finished bore.
              me too.
              Didn't think to get a pic of it. The finish was pretty good, if i remember ill snap a shot.
              ~ What was once an Opinion, became a Fact, to be later proven Wrong ~
              http://site.thisisjusthowidoit.com
              https://www.youtube.com/user/thisisjusthowidoit

              Comment


              • #8
                Nice job, i would call it line boring myself, well its a line shaft with a boring cutter!,nice vidio too
                Mark

                Comment


                • #9
                  Thanks Mark.

                  plunger, something else to consider, the bar being used. If the bar is bent it will create an elliptical (or 'U' shaped) bore when it rides through the bushing (the bushing will be acting as a guide), dont think you would want that for a tail stock. Just thinking out load here for my own notes, indicate the boring bar tool holder so its perfectly concentric with the spindle, make sure the bed of the machine is running parallel and not raked/twisted, use two bushings - one on each end of the spindle to help support the boring bar, lock the X. Worst case, bore it over and press a sleeve into the tail-stock housing to make up for any imperfections that might happen while boring.
                  ~ What was once an Opinion, became a Fact, to be later proven Wrong ~
                  http://site.thisisjusthowidoit.com
                  https://www.youtube.com/user/thisisjusthowidoit

                  Comment


                  • #10
                    Regarding boring the tailstock, you would need to chuck the boring bar since unlike boring the spindle the tailstock won't be spinning.
                    Location: Long Island, N.Y.

                    Comment


                    • #11
                      Originally posted by RichR View Post
                      Regarding boring the tailstock, you would need to chuck the boring bar since unlike boring the spindle the tailstock won't be spinning.
                      hahaha... im a fool, yea, guess your right

                      _
                      ~ What was once an Opinion, became a Fact, to be later proven Wrong ~
                      http://site.thisisjusthowidoit.com
                      https://www.youtube.com/user/thisisjusthowidoit

                      Comment


                      • #12
                        Originally posted by iMisspell View Post
                        hahaha... im a fool, yea, guess your right

                        _
                        But if your bush in the chuck was keyed and the carriage travelled to your right it would still be held true by the chuck. If you had a seriously thick ground and true bar that was keyed in the chuck and the end was clocked up in a steady and the carriage was merely used to pull the bar through the tailstock it could work

                        Comment


                        • #13
                          I'm just an amateur here but I'd have to say apples and oranges. With the spindle you are just boring for clearance, and have more leeway on how accurately
                          the cut is made. With the tailstock, I'd think fit, finish, and alignment become more critical. The following issues come to mind:
                          1. Prior to boring, you need to be sure the tailstock flat on the ways, ie. doesn't rock.
                          2. Depending on how the ways are worn, placement of the tailstock when boring will affect the hole location and possibly angular alignment.
                          3. I think tailstocks usually point high by like 0.0005" to allow for wear.
                          4. Boring may affect a keyway.
                          5. If you plan on boring by sliding the tailstock, you need to be able to clamp it tight enough so it doesn't lift, and loose enough so it still slides.
                          6, You probably need to hone it for a good finish.
                          7. A dozen other issues that didn't even occur to me.
                          Location: Long Island, N.Y.

                          Comment


                          • #14
                            I've been wondering about doing this to my lathe, you gave me the incentive to try it, and I'll try it before long, I've got a smaller lathe than you and the spindle hole is like boot camp uniforms, no matter the size, it's the wrong size.
                            olcop

                            Comment


                            • #15
                              I can't see the you tube videos, but I did a similar operation on my Taig when it was new. IIRC, I used a 3/8 drill in the tailstock. IDGAF about the spindle taper. I've never used it in the nearly 30 years I've owned the lathe. Face plate, 3, and 4 jaw chucks yes, but a center in the headstock - never.

                              I'm an amateur for sure, but frankly, I've never used a spindle taper in either my Taig nor my 1440. the old Rockwell has a center stuck in the spindle I haven't got the courage to knock loose....
                              Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

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