Announcement

Collapse
No announcement yet.

Making a real thin washer

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Making a real thin washer

    A mate of mine does jewellry. He cuts stones with a diamond blade that is about a 120mm by 0.35mm thick.The hole in the blade is 16mm. This is where the problemstarts. THe bolt that is on his machine is 1/2 inch so he has problems lining up the blade so it is running true.He has asked me to make a washer of sorts to eliminate this problem but I dont know how to machine such a thin washer Any suggestions? It is called a graves machine but I havent seen it as all he gave me is the nut and blade.

  • #2
    This kind of task is all about workholding. Use either soft "pie" jaws on a lathe chuck to hold the outer diameter (think Taig) or an emergency collet. Cut OD to size from solid. Drill pilot hole much smaller than finished washer ID. Part to thickness required. Turn soft jaws or emergency collet to size. By this, I mean bore a recess to the OD of the washer and at least as deep as the washer's thickness. Then machine a second step roughly at the diameter of your finished washer's ID. Mount work in chuck/collet. Slowly bore out the ID of the washer to the size you want. Use light cuts.
    Last edited by Arthur.Marks; 09-21-2011, 01:26 AM.

    Comment


    • #3
      Use super glue to hold the blank, turn it to size, then use acetone (or fingernail polish remover) to release it.

      Comment


      • #4
        The first thing I'd do is get two more nuts of the proper size. (Two, so I can screw one up.)

        Chuck up the nut and face it true on the side which will meet the blade. Then face it, leaving a 0.35mm +0-.01 ridge, 16 mm in diameter. That means the wall of the ridge will be about 1.65mm thick.

        This might not work, but it is the first thing I'd try, before trying to make such a thin piece.

        Pops

        Comment


        • #5
          So you need a spacer which is .35 m thick, 1/2 inch ID, and 16mm OD. Start with a piece of bar at least 16 mm in diameter. Turn it down to about 3/8 diameter for about 3/4 inch, and face the part from the 3/8 diameter to the full OD. Part it off leaving about .07 or so in thickness of the larger diameter. Then reverse it in the chuck, turn the OD down to 16mm, then face off until you have .35 mm thickness left. Switch to boring and go straight in making a 1/2 inch diameter bore. The washer part will come right off, properly sized all around, and needing only deburring.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

          Comment


          • #6
            I must be missing something.
            Chuck a piece of round, face, drill/bore ID, turn OD, part off a .3 washer (a bit less than the thickness of the diamond blade, or saw it off since it is only a spacer).
            Location: North Central Texas

            Comment


            • #7
              Presumably the blade is mounterd with a flange on either side so: Make/use a thicker washer/flange at say 30 mm diameter with a 16mm upset on it at 0.3mm high.

              Alternatively make a second washer/flange for the other side of the blade that fits over a 1mm x 16mm diameter upset on the other washer/flange.

              Alteratively look at a sltting saw arbour. 16mm shaft with shoulder, blade between two washers with an end cap to clamp the whole lot together.

              Phil

              Comment


              • #8
                You don't need to make a washer. Just take the nut and face one side leaving the spacer you need part of the nut. Just as on an angle grinder nut.
                Location: The Black Forest in Germany

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

                Comment


                • #9
                  The blade probably needs to run true to a reasonably high degree of precision/concentricity.

                  Phil

                  Originally posted by Black Forest
                  You don't need to make a washer. Just take the nut and face one side leaving the spacer you need part of the nut. Just as on an angle grinder nut.

                  Comment


                  • #10
                    Nuts often don't run true to their threads, so I wouldn't count on that approach working.

                    What would work better is to chuck up a piece of scrap round bar, thread the end leaving a shoulder, mount the nut on the stub thread, and then machine the locating shoulder on the other end of the nut. That way the shoulder is going to run true to the threads regardless of how well the nut is made.

                    Don't remove the stub thread from the lathe chuck until you're finished modifying the nut(s).
                    Any products mentioned in my posts have been endorsed by their manufacturer.

                    Comment


                    • #11
                      OK, good point. So make a new nut and make all the features without unchucking and then part off.
                      Location: The Black Forest in Germany

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

                      Comment


                      • #12
                        I like the idea of making the stepped nut. The other ideas are good too.

                        Here's another way of doing it, in case none of those ideas appeal to you. Get a piece of 0.30mm shim stock and clamp it down tightly to your milling machine table sandwiched between two very flat pieces of aluminum that are perhaps 6mm thick. Proceed to drill and ream the 1/2" center hole through the sandwich. (This operation could also be done on a lathe faceplate, if need be.)
                        Remove the sandwich, extract the piece of shim stock with its 1/2" hole, and mount it in the lathe on a true-running stub arbor sandwiched between two flat washers that are a bit more than 16mm in diameter. Proceed to turn the assembly down to 16mm.
                        ----------
                        Try to make a living, not a killing. -- Utah Phillips
                        Don't believe everything you know. -- Bumper sticker
                        Everybody is ignorant, only on different subjects. -- Will Rogers
                        There are lots of people who mistake their imagination for their memory. - Josh Billings
                        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                        Don't own anything you have to feed or paint. - Hood River Blackie

                        Comment


                        • #13
                          Originally posted by Joel
                          I must be missing something.
                          Chuck a piece of round, face, drill/bore ID, turn OD, part off a .3 washer (a bit less than the thickness of the diamond blade, or saw it off since it is only a spacer).
                          That's what I thought of also...
                          I have tools I don't even know I own...

                          Comment


                          • #14
                            Originally posted by torker
                            That's what I thought of also...
                            Exactly?

                            Just take a piece of round stock, drill out the ID, turn down the OD, and part off...

                            You can part the thing as thin as you want.

                            If precision is required then part slightly oversized and lap on a surface plate. This will also improve the finish from parting.

                            I wouldn't bother attempting to hold and turn a 0.3mm thick washer... You could I suppose, but what's the need?

                            Comment


                            • #15
                              But what about the precision/concentricity of the thread on the shaft.

                              Phil

                              Originally posted by Black Forest
                              OK, good point. So make a new nut and make all the features without unchucking and then part off.

                              Comment

                              Working...
                              X