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9/16" Spiral Flute Reamer, Over Size

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  • 9/16" Spiral Flute Reamer, Over Size

    Any one know where I could buy an oversize reamer, 9/16" with spiral flutes? Everywhere I look has either spirals or oversize, but not both at the same time.
    Paul A.

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

  • #2
    How much oversize ?

    You can get a few tenth by using the old toolmaker trick of rubbing a hardened dowel pin along the gullet of the flutes from tip to shank.
    This has the effect of throwing a burr up and adds the tiny bit on.

    You can also undersize one by doing the same but with the pin on the tops of the flutes.

    .
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



    Comment


    • #3
      There is also the one where you pack the flutes on one side with hardwood strips, to force the reamer over to one side. Its OK for 'easing', but I wouldn't like to use it for exact sizing, i.e 9/16 +0.005"

      Richard

      Comment


      • #4
        You can also slightly influence the size it cuts by using either oil (bigger) or coolant (smaller).

        While we are at it:
        Has anyone got I good procedure how to measure reamers? It's quite difficult to exactly catch the narrow cylindical strip and to get precise results.
        Background: I sometimes regrind reamers to different sizes, so a calibration ring won't work. Also, I don't want to ream test bores.

        If all fails, ream and then lap to the desired size. Not too time consuming.


        Nick

        Comment


        • #5
          V-anvil micrometer

          Nick.

          Try these or a variation of them on a normal micrometer:

          V-anvil micrometers at:
          http://www.cdcotools.com/

          search for items:
          32344 - 3 flutes (60 Deg.) (up to 1"); and

          32355 - 5 flutes (108 Deg.) (up to 1").

          I've seen a half-round (concave) adaptor on the fixed anvil - but it needs to be calibrated or noted against a known test piece. It is similar to the "hollow" fixed anvil micrometers used to set the tools in boring and line-boring bars.

          It will be obvious that these are "inch" and Chinese but I'd bet that you will find a good European metric version.

          Comment


          • #6
            V-anvil micrometers at:
            Ouch! I didn't get that idea!
            Two problems:
            Some reamers do have their flutes not symetrical (to reduce chatter)
            I need it in µm resolution, and until now, I didn't see ones. Might be verrrrry expensive too.

            But the idea with the hollow anvil looks promising, maybe I find something that fits.


            Thanks,
            Nick

            Comment


            • #7
              OS

              use water instead of cutting fluid, reamer will bite into metal harder, and take out more metal.
              FORD BEATING JAP CRAP SINCE 1941!! CAROLYN JONES(1930-1983 actress)may this lady never be forgotten.

              Comment


              • #8
                Originally posted by John Stevenson
                How much oversize ?

                You can get a few tenth by using the old toolmaker trick of rubbing a hardened dowel pin along the gullet of the flutes from tip to shank.
                This has the effect of throwing a burr up and adds the tiny bit on.

                You can also undersize one by doing the same but with the pin on the tops of the flutes.

                .
                "Over" and "Under" sized usually refers to 0.001" over or under: at least, in all the catalogs I have seen. Some sources have Over and Under sizes, but always in a straight flute, not spiral. I will be doing a final ream on a keyed part so spiral would be best. I would settle for 0.0005" over, but no bigger than 0.001" over.

                I have read about all the tricks but since I will be doing multiple parts, it would be nice to have the actual size I need.
                Paul A.

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

                Comment


                • #9
                  How much are you willing to spend? I know I've run across a couple of places that will make custom reamers and other cutting tools with no minimum quantity. I expect you'd have to pay quite a bit for a one-off cutter, though ...

                  Alternatively, since you have a little room to play, any thoughts on making your own? Probably not worth the time and effort but it could be an interesting project... Not sure I know a quick and easy way of making a spiral reamer, though...

                  Comment


                  • #10
                    MSC has over/under reamers in stock.

                    Toolmakers trick. To run OS, take an old carbide insert and run it in the inside of the flute, raises a burr. To make US, run the insert on top of the flute on the relief, pushes the burr in. Problem with this over the wood stick method (Guy lautard says a wood matchstick) is that this is permanent. I have a set of .001 OS nominal by 1/8 and a few of the copmmon 16th OS and undersize, I used the insert method.
                    CCBW, MAH

                    Comment


                    • #11
                      "D" bit?

                      Drill and/or bore under-size and finish off with a shop-made "D" bit - silver steel (here and UK) or O1 (US) will do fine.

                      http://en.wikipedia.org/wiki/Silver_steel

                      http://en.wikipedia.org/wiki/Tool_steel

                      http://www.google.com.au/#hl=en&q=dr...d4e774e7976426

                      http://www.google.com.au/#hl=en&q=d+...d4e774e7976426

                      Comment


                      • #12
                        I've got a set of cheap over/under fractional reamers from tiny (0.062?) up to 0.500 by 64ths. And it is over/under by 0.0001. Great for assembly/alignment pins and such.

                        But if you need some serious range, say a few thou, perhaps an adjustable chucking reamer is your best bet? I just had a job where I needed a nice (but not perfect) hole 12" long at "several thou" over 1". So I got a long 1" adjustable chucking reamer. Adjusted to 1.007 and with a short shop made extension, it was just the thing. Why must it be spiral?
                        Russ
                        Master Floor Sweeper

                        Comment


                        • #13
                          In the "low um" range/s

                          Originally posted by MuellerNick
                          You can also slightly influence the size it cuts by using either oil (bigger) or coolant (smaller).

                          While we are at it:
                          Has anyone got I good procedure how to measure reamers? It's quite difficult to exactly catch the narrow cylindical strip and to get precise results.
                          Background: I sometimes regrind reamers to different sizes, so a calibration ring won't work. Also, I don't want to ream test bores.

                          If all fails, ream and then lap to the desired size. Not too time consuming.

                          Nick

                          Originally posted by MuellerNick
                          Ouch! I didn't get that idea!
                          Two problems:
                          Some reamers do have their flutes not symetrical (to reduce chatter)
                          I need it in µm resolution, and until now, I didn't see ones.
                          Might be verrrrry expensive too.

                          But the idea with the hollow anvil looks promising, maybe I find something that fits.


                          Thanks,
                          Nick
                          Nick.

                          From my T&C grinding days from long ago. Its an oldie but a goodie (sorry about the rough sketch but ................................... ):



                          The reamer/cutter outline with a single tooth is shown as if mounted between centres as it is ground on a T&C grinder. It has a (preferably "springy" brass) strip bearing on it. The strip is fastened at the left end and can "float" on the right end. A good (in this case 2um = 0.002mm ~ 0.00008") test indicator is mounted on the brass strip and set to zero on a test/guage piece (also mounted between the same centres).

                          The reamer/cutter is rotated "back-wards" - anti-clock-wise in this case - so as not to damage the cutting edges.

                          The indicator will show the amount over or under size as the tool/reamer is ground.

                          The indicator and strip set-up can optionally be on either a test rig or the T&C grinder.

                          Its simple, its accurate and it works.

                          With this sort of work the grinding wheel starts its cut at the cutting edge of the primary land so as not to leave a grinding "edge" or "burr" - which is the exact opposite to manual T&C grinding of end-milling and other cutters. It requires a high level of skill, co-ordination and dexterity as it is tending to "lift" the cutter from the guide/finger and if it "gets away" the cutter/reamer will "spin" on the centres (driven by the grinding wheel!!) and it gets "interesting" as there are sparks and wheel chips and dust everywhere.

                          The "edge" or "burr" doesn't matter on a normal cutter as it can be "stropped off" with a diamond honing stick or a bit a good hard-wood - or even hard brass.

                          The sketch is of the basic principles and can be changed to suit you as you wish.

                          I think that this will meet your "low um" requirement in any HSM shop with a good T&C grinder and a very good operator - you seem to fill those requirements admirably.

                          Comment


                          • #14
                            The sketch is of the basic principles and can be changed to suit you as you wish.
                            That is a very good setup for checking during work!
                            I do have some spring bronze sheet metal.

                            I think I'll even take that route for measuring the absolute value. Surface plate, gauge blocks, that spingy-thingy and a DI. Sounds good!


                            Thanks for that trade secret.


                            Nick

                            Comment


                            • #15
                              Tbanks

                              Thanks Nick.

                              Glad to help.

                              That's what we are here on this BBS for - isn't it?

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