Chuck material holding question

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  • Mr Fixit
    Senior Member
    • Nov 2010
    • 1355
    #1

    Chuck material holding question

    Hello Group,

    I have a 3 jaw chuck on a SB9 lathe and need to recut the MT 2 dead center tip and can't get the taper to hold true in the chuck so I can fix it..
    What advice can you give for setup to true it up and how to clamp it in the chuck. I tried shimming, no go, I don't have a female MT 2 square socket to chuck it up into so I'm at a loss as to what to do next.

    TX
    Mr Fixit for the family
    Chris
    Tags: None
  • garyhlucas
    Senior Member
    • Mar 2013
    • 2407
    #2
    Drill a piece of bar stock with a fairly large hole, then turn the same female taper inside. Don't remove it from the chuck, it'll be as perfect as your lathe can possibly do. Tap the center in tight and cut it. If you need to do it again always touch up the taper true.

    Comment

    • firbikrhd1
      Senior Member
      • Mar 2001
      • 1610
      #3
      I don't know what I'm missing here. Does your lathe have an internally tapered headstock spindle? If so thrust the center into the spindle and take light cuts to true the center.
      Sorry if I'm not understanding the problem. Perhaps the SB9 has only a #1 MT taper in the spindle. In that case garylucas advice above is a good method. From what I can gather about the SB 9 it has a #2 MT spindle hole.

      http://www.wswells.com/data/catalog/1934_bulletin_5-E/1934_bulletin_5-E.pdf

      Comment

      • J Tiers
        Senior Member
        • Jan 2004
        • 44397
        #4
        Southbend has an MT3 in the spindle, like most 1 1/2-8 threaded machines, so one could use a good quality 3 to 2 adapter to do the job.
        CNC machines only go through the motions.

        Ideas expressed may be mine, or from anyone else in the universe.
        Not responsible for clerical errors. Or those made by lay people either.
        Number formats and units may be chosen at random depending on what day it is.
        I reserve the right to use a number system with any integer base without prior notice.
        Generalizations are understood to be "often" true, but not true in every case.

        Comment

        • Bob Fisher
          Senior Member
          • Jan 2006
          • 1341
          #5
          You really should own an adaptor or sleeve. They are not expensive and you will find a lot of use for it. Mc Master Carr has one for less than $ 15.

          Comment

          • Richard P Wilson
            Senior Member
            • Aug 2012
            • 2145
            #6
            By 'dead' centre, I presume you mean the one for the tailstock end? If so, then it will be hard. If it isn't hard, then its a live centre, and will quickly burn out if you use it at the tailstock end. Even when you've got it set up, will your tooling touch it? I agree with J Tiers and Bob Fisher, get a 3-2MT sleeve, (assuming your spindle nose is bored 3MT), and plug it in there.
            'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

            Comment

            • Mike279
              Senior Member
              • May 2013
              • 363
              #7
              Can you use the tail stock holder? My Atlas will release on extension and can be easily chucked in the 4 jaw pretty accurately. Mike

              Comment

              • Mr Fixit
                Senior Member
                • Nov 2010
                • 1355
                #8
                Thanks Gang,
                I didn't know that it is hardened my HHS tools would not even cut it then. Looks like I will be ordering a adapter and a live center as the reason for this post is I burnt the tip on the dead center. I have since learned that when using the dead center for a longer turning project you have to lubricant it just like our cutting tools.

                TX
                Mr Fixit for the family
                Chris

                Comment

                • 10KPete
                  Senior Member
                  • Jan 2009
                  • 933
                  #9
                  Originally posted by Richard P Wilson View Post
                  By 'dead' centre, I presume you mean the one for the tailstock end? If so, then it will be hard. If it isn't hard, then its a live centre, and will quickly burn out if you use it at the tailstock end. Even when you've got it set up, will your tooling touch it? I agree with J Tiers and Bob Fisher, get a 3-2MT sleeve, (assuming your spindle nose is bored 3MT), and plug it in there.
                  I've run across this before so want to make sure there is no misunderstanding here:

                  In the US a dead center is a solid piece and can be used at either end of the lathe and a live center has a bearing
                  so the point can spin and is usually used in the tail stock. Our dead centers are usually hard. We used to use the
                  softer live center but since the bearing center came along the solid live center has fallen out of use.

                  In the UK a dead center is a solid piece used at the tail stock. But the same piece used in the head stock is called
                  a live center because it now is turning with the spindle. What we call a live center they call a bearing or rotating
                  center. While the piece is the same size, the dead center is hardened and the live center is not.

                  CHRIS: You should be able to put your center in the spindle with an adaptor and turn it. If you have a carbide
                  you might be able to cut it. I have done this in the past and a lot of the 'hardened' centers aren't so hard that
                  a good, sharp, carbide won't cut. Worse case use a Joe McGee rig to put a Dremel on the tool post and grind
                  it!

                  Pete
                  Last edited by 10KPete; 01-17-2016, 06:18 PM.
                  1973 SB 10K .
                  BenchMaster mill.

                  Comment

                  • LKeithR
                    Senior Member
                    • Sep 2011
                    • 1735
                    #10
                    Can't believe I've read this whole thread and no one has suggested just going out and buying a new centre. Throw the old one out and move on. If I counted them all up I've probably got 20-25 centres (live and dead) kicking around the shop. Some I've bought, some came with machines, some came in mixed boxes of stuff I've purchased and over the years I've been given a few as well. You can't have too many...
                    Keith
                    __________________________
                    Just one project too many--that's what finally got him...

                    Comment

                    • 10KPete
                      Senior Member
                      • Jan 2009
                      • 933
                      #11
                      That's nice but it doesn't take care of the "I need it now!!!" problem. I don't know if that's what Chris is up against but
                      I know I have hit that roadblock occasionally! I only have two dead centers and one live (bearing) center so I can see
                      where the problem could happen. But... naaa, won't. I hope.

                      Pete
                      1973 SB 10K .
                      BenchMaster mill.

                      Comment

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