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Round HSS Blanks to... Boring bars?

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  • Round HSS Blanks to... Boring bars?

    I find myself with quite a few HSS round blanks of diff sizes, but the
    majority of the gang is 3/8" to 1/2" OD. They're all about 8" long.

    Got them in a mixed box of HSS tooling quite some time ago.. I've put all
    the square section HSS to work

    So I'm looking for ideas for the round blanks (to date I've been using
    them for setups / measuring / stuff like that) -- and I'm considering
    turning them into boring bars.

    I could get all the angles on the end except the side relief of course..
    I'd rather not grind down the full length. I suppose I could bore with
    the tool swung over 5-8 degrees or so.

    In the lathe at least. No dice for the boring heads.

    What're the odds I could heat the end and give them a bit of a bend?
    (Yeah, thats what I thought too).


  • #2
    I have only ever read of the forging method for steel the likes of 0-1. I can't say for certain it wouldn't work for HSS, but I have a healthy dose of skepticism. At the least, you are guaranteed to temper the cutting edge. How would you re-harden it?? The traditional approach is to grind a clearance flat for the necessary length of the bore. It doesn't have to be pretty, of course---or much of a flat at all, really. All you need to do is keep it from contacting the workpiece bore. If you have a tool grinder this is easy. I have a small bench mill I don't mind mucking up with abrasives that I sometimes grind small features with. Just chuck up a small Al.Ox. burr and run it down the length of the blank for a good ways (not on the cutting tip! ) The quick and dirty method would be a burr in a hand drill or die grinder to make the flat... I think you get the idea. Dunk in water often. You don't want to lose hardness on the cutting tip.
    Last edited by Arthur.Marks; 12-29-2011, 03:10 PM.


    • #3
      Boring Bar

      For the lathe, you can make the cutting part on the end, then set up with the bar at a slight angle rather than straight to give clearance.
      For the boring head that won't work unless you turn down the shank from 1/2 to 3/8 at an angle to the rest of the bar. That would seem a little impractical though.
      Kansas City area


      • #4
        chop them in half and using them for milling in a boring head or fly cutter .

        all the best.markj


        • #5
          D bit reamers perhaps, if diameter suits.

          Boring bars, but you have to angle the bar, or grind the clearance. Even grinding the clearance is FAR easier than on square as long as the min diameter of bore is bigger than the bar by a bit.

          Ground like a D bit reamer with appropriate rake and adding some side clearance for using in a boring head makes sense.

          I ground several into slotting head bits. Lots of work there.
          Master Floor Sweeper


          • #6
            You don't have to find an immediate use for everything you have. You put them on the shelf, one day you will come up against a situation that is a perfect match with your HSS rounds, trust me. You biggest problem will be that you forget you have them, if not then you don't yet have enough (maybe I need it later) stuff on your shelves.



            • #7
              Originally posted by Arthur.Marks
              I have only ever read of the forging method for steel the likes of 0-1. I can't say for certain it wouldn't work for HSS, but I have a healthy dose of skepticism.
              O1 forges very nicely. So does W1/W2. S5/S7 is stiff, but still workable. I haven't forged A2 yet -- my mentors tell me it's tricky because it air hardens, but still emminently forgeable.

              High-speed steel, on the other hand, is like trying to hammer rocks. It has very high red hardness (duh!), so even at near forging temperatures, it won't move much, and you're probably wrecking the grain.

              Then, like Arthur says, you have the issues of re heat treating it.
              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


              • #8
                These aint "boring bars", they are just Toolbits for boring bars.

                You need a approprate holder- the boring bar. Just a piece of round Stock with a round hole in it to fit these Toolbits. (And a clamp screw)

                For corner and facing work the hole would be angled at 45° axially.



                • #9
                  I use lots of round 1/4 inch HSS tool bits - especially if I need a very small boring bar for threading. I bend the end by heating it with an oxygen/acetylene torch. Here's an example of one that I used for internal threading of a 1/2"-10tpi acme nut.