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How Can I Bore This And Avoid Another Mill Set Up

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  • How Can I Bore This And Avoid Another Mill Set Up

    I should have done this when I bored the head for the quill sleeve but didn't. All I would have had to do is flip the head over on the mill. Now after the final assembly I noticed that there is a bit of play in the hole for the intermediate pulley. The stud on the arm is .5585 and is good all the way around. The hole originally was .559 as that size pin goes through,and the .560 goes in about 7/16" and wobbles slightly, the .561 goes in about 1/4" so you can see what kind of shape the hole is in. The depth of the hole is 1" I'm going to have to open it up to 5/8" and make a bushing but I would like to come up with a way to do it without taking everything apart and setting it up on the mill again. I know I can't drill it by hand with any accuracy or ream it open to 5/8" so I'm wondering if any one has any suggestions??

    JL.........





  • #2
    Paging John Stevenson. Would you please come to the front. We have a customer that needs your assistance. Hello Sir, Mr. Stevenson will be along in a minute and he will have a couple of words for you. Please wait. Thank you and have a nice day.
    Location: The Black Forest in Germany

    How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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    • #3
      Unrealistic, but one of these is designed to do just that type of in-place machining.

      http://versamil.com/

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      • #4
        Bolt a flat plate on and use a mag base drill - if you have access to one ?

        Make a drill jig from a lump of flat plate with a boss welded on, with slotted holes at the ends for alignment, then bore the boss on the mill and use this as a guide for a hand drill then reamer.

        if you're putting a bushing in it doesn't have to be perfect throughout, a bit of threadlock will fill a thou or two and mean surface finish doesn't matter either.

        Another thought, the jig could be a flat plate that you bolt a round boss onto then you could drill the hole undersize with a power drill, then remove the boss, open it out in the lathe and then use it to guide a hand reamer.


        In reality does it matter, it's just a tensioning pully by the looks of it.

        Brian

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        • #5
          I think I might use my Unimat to bore it. Lower the casting as much as possible on the DP's column to expose at least a foot or so of it above the casting. I have a rectangular block with several Unimat mounting holes on it that can be fastened to the DP's column. Then the Unimat column to that (mounted horizontally) and the Unimat head to the Unimat column. It would take some effort, but this set-up would allow the Unimat spindle to be centered over the existing hole. Then bore away.

          Perhaps other types of small milling spindles could be used in a similar manner. Or perhaps a magnetic drill.
          Paul A.
          SE Texas

          Make it fit.
          You can't win and there IS a penalty for trying!

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          • #6
            Why not use the spindle bore and make a jig with a drill guIde tofix the hole!
            Location: The Black Forest in Germany

            How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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            • #7
              You mean something like this??? I made this when I had to drill and tap my lathe bed for scales. If I were to make something similar it wold have to clamp to the top of the spindle pulley to ensure that the hole is in line with the DP's spindle.


              JL....................


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              • #8
                Turn down the stud to 0.5512" (14 mm). Hand ream the bore to 0.5625" (9/16") and press fit a thin (~0.005" wall) 14 mm ID, 9/16" OD brass bushing.
                Last edited by Arthur.Marks; 12-13-2014, 04:37 PM.

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                • #9
                  Originally posted by Arthur.Marks View Post
                  Turn down the stud to 0.5512" (14 mm). Hand ream the bore to 0.5625" (9/16") and press fit a thin (~0.005" wall) 14 mm ID, 9/16" OD brass bushing.
                  That won't solve much as the hole isn't round as I stated in my first post. A thin bushing like that would only conform to the oblong hole and nothing would be gained.

                  JL..................

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                  • #10
                    Hi JoeLee
                    If you start with a 9/16" drill bit and work your way up by 64ths to 5/8" won't the bits just follow the original hole? Then turn your bushing to match the hole
                    and install with some retaining compound.
                    Location: Long Island, N.Y.

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                    • #11
                      It's fun to make wise cracks, but rather I'll just ask......... Why?

                      A couple insignificant thou for all that... Why?

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                      • #12
                        Set it up in the mill again and machine it properly as you'll probably spend more time trying to find a work-a-around. You did a great job so far, why risk ruining it!

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                        • #13
                          I doubt the very slight play will make any difference. The shaft and it's retainer only rotate slightly when changing belts. You just need a close enough fit to keep the pulley from excessively cocking out of plane.

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                          • #14
                            Yep, going though all this trouble won't make a bit of difference in the end if there is a bit of slop in there.

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                            • #15
                              Originally posted by JoeLee View Post
                              That won't solve much as the hole isn't round as I stated in my first post. A thin bushing like that would only conform to the oblong hole and nothing would be gained.
                              I wholeheartedly disagree. The hand reamer will make it round, on size and a true cylindrical hole of 9/16" diameter. I'm not talking about a chucking (machine) reamer here--but a hand reamer.
                              Last edited by Arthur.Marks; 12-14-2014, 04:55 AM.

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