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  • expanding mandrel

    Hi
    Does anyone know where I can buy an expanding mandrel
    with a size from 95-102mm or 3.750-4.000"?

    I tried the usually: Travers,KBC, Shars etc with no luck.

    eddie
    please visit my webpage:
    http://motorworks88.webs.com/

  • #2
    Dunham makes their "Miser Mandrels" up to 6". I have the MM1, 2, 3, which MSC carries. They're much nicer than the Chinese copy (which I also have).

    The MM5 (Miser Mandrel 5) goes 3/4" to 4 3/4", and the MM6 goes 3/4" to 6 1/4"

    http://www.dunhamtool.com/expanding_mandrel.html

    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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    • #3
      mandrel

      Google Rovi collets made in Calfornia
      I have used them for years and they go up to 6 inches.
      Jim

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      • #4
        Dunham has those machineable 5C expanding collets too -- are they expensive? I nabbed a couple of the Dunhams on Ebay, but they're something like $120 each retail.
        "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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        • #5
          Soft jaws

          Is there any reason why a 3-jaw chuck with soft jaws won't do the job?

          Comment


          • #6
            mandrel

            I have the collet parts and bought them years ago. So don't know what prices are in todays market, but the expanding mandrel part in a 4 inch size is
            about $80 to $100 bucks. Depends on length of them. I have used them from 5/16 dia up to 6 inch size in their 5c type.
            Jim

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            • #7
              Originally posted by oldtiffie
              Is there any reason why a 3-jaw chuck with soft jaws won't do the job?

              Nope, suppose they would be even quicker to do it, than mucking around with a mandrel.

              Comment


              • #8
                OP's choice

                Originally Posted by oldtiffie
                Is there any reason why a 3-jaw chuck with soft jaws won't do the job?
                Originally posted by radish1us
                Nope, suppose they would be even quicker to do it, than mucking around with a mandrel.
                Thanks radish1us.

                I was going to add that if a 3-jaw chuck with soft jaws was available, the cost - providing the soft-jaws were in the shop - would be about zero. A new three jaw chuck with soft jaws may well be an ultimately better and cheaper option than expanding mandrels. There must be a finite limit to which the expanding mandrel can be turned each time to achieve a set nominal size before being "down-sized" at which stage a new expanding mandrel may need to be bought.

                Longer - in this case, hollow - parts whether held on an expanding mandrel or in soft jaws - will or may require to be supported by a disk or similar which in turn is supported by the tail-stock - or perhaps a fixed (or "traveling"??) "steady" or a "spider".

                Still its the OP's "call" or choice.

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                • #9
                  Thanks guys
                  Thoses "Miser Mandrels" look easy to make
                  but I would have to make two as there are two
                  parts to the bushing job and two different bores
                  (95mm for the rough and 100mm finish)

                  I was looking for the tapered type that work over a greater range.
                  I may just make two solid taper mandrels (0.0005"/1")
                  one for the 95 and one for the 100mm.

                  I though about 'soft jaws' but I need to hold both by the bore
                  and they are 110mm long.
                  Thought it may work with the disc idea/ 2 discs! ( thanks oldtiffie)


                  eddie
                  Last edited by motorworks; 01-04-2009, 09:33 AM.
                  please visit my webpage:
                  http://motorworks88.webs.com/

                  Comment


                  • #10
                    I haven't personally seen taper-expanding ones over about 2". My set goes to 1.5" IIRC.

                    I see the machinable ones as really for a production job. You need something of a commitment to spend $100 on a tool for one job. Or 2x that for two different tools for one job.......
                    1601

                    Keep eye on ball.
                    Hashim Khan

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                    • #11
                      McMaster-Carr lists one,3-1/4-4"..............$1275

                      Here is an interesting concept-

                      http://www.holdid.com/IDHOLD-XPANDREL.htm

                      What about a rotating tailstock chuck?
                      I just need one more tool,just one!

                      Comment


                      • #12
                        Originally posted by motorworks
                        Thanks guys
                        Thoses "Miser Mandrels" look easy to make
                        Yep, looks like a quick project. It's just a bored cylinder with radial slits and a tapered plug to spread it. I've heard folks use an NPT plug to spread homemade expanding mandrels.

                        By the way, the cool feature about the 5C collet mandrels like Jim Sehr posted is they screw into the 5C drawbar, and the drawbar pulls the taper plug.

                        So you put the workpiece on the mandrel, pull the drawbar lever, and the mandrels grabs and you're off to the races...
                        "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                        Comment


                        • #13
                          Originally posted by motorworks
                          I though about 'soft jaws' but I need to hold both by the bore
                          and they are 110mm long.
                          Thought it may work with the disc idea/ 2 discs! ( thanks oldtiffie)


                          eddie
                          How about soft jaws turned to grasp the bore on one end, and a bull center to locate the other end. I've done this but with standard ID jaws and bull center for turning the OD of heavy wall DOM tube. You could even make a TS "live mount" and make a "hat" of appropriate size with small taper on the insert section, sized for the job of the day...
                          Russ
                          Master Floor Sweeper

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