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5C Collets For Tap Shanks

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  • 5C Collets For Tap Shanks

    Does anyone know if some one makes 5C collets that fit the odd sizes of tap shanks ?

    I have several taps where I need to grind a smaller point on the square end so it will fit into my spring loaded tap guide.

    Some of the larger taps have a small pilot hole which is OK because my guide has a reversible end. I guess it also depends on the mfg. of the tap.

    An example would be a 1/4" tap that I have. The shank measures .2535, 6.44mm. It's a little too big to try and squeeze into a 1/4" collet. I know I could make a

    bushing and go to a larger collet but I want to try and minimize my error.



    JL.................

  • #2
    I'm pretty sure that with a bit of looking around that 5C collets come in half mm steps. And a 6.5mm collet would work for the size you have.

    And yet another option is to buy a few emergency collets and drill then bore out the size you need for each special size. They are softer so they can be machined but it's not like you'll use them a whole lot. And emergency collets can be had for pretty cheap.
    Chilliwack BC, Canada

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    • #3
      Originally posted by BCRider View Post
      I'm pretty sure that with a bit of looking around that 5C collets come in half mm steps. And a 6.5mm collet would work for the size you have.

      And yet another option is to buy a few emergency collets and drill then bore out the size you need for each special size. They are softer so they can be machined but it's not like you'll use them a whole lot. And emergency collets can be had for pretty cheap.
      That's a good idea. But the cost of some of those "emergency" collets is more than a regular hardened one.

      I checked Lyndex and could only find half mm in ER collets.

      JL...............

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      • #4
        5c collets are available in whatever decimal size you care to order. Not cheap.
        https://shophardinge.com/productGrid.aspx?catID=6896

        edit: or see if the size you need is here
        https://www.ebay.com/itm/Hardinge-5C...-/174436577890
        Last edited by MrWhoopee; 04-06-2021, 11:09 PM.
        It's all mind over matter.
        If you don't mind, it don't matter.

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        • #5
          Less expensive than a custom collet to hold taps, you can buy tap holding bushings meant for releasing tapping heads. Somma and Boyar-Schultz are two companies that sell them. The ones I have are hardened and ground, 1/2" diameter split on one side with a square to match the tap's square end.

          Like everything else in tooling these days I suppose they're expensive.

          You could also buy tap holding bushing like those on my bench hand tappers. Those might be the least expensive since they aren't hardened. The ones I have are 3/4" diameter with a set screw to hold the tap. They also have the broached square in the end.

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          • #6
            Any chance of switching over to ER collets on your tap grinder?

            Ian
            All of the gear, no idea...

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            • #7
              do you mean a colled with a square hole?

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              • #8
                I think he just means a collet with a plain round hole, as he's only sharpening the tap which doesn't take much torque. He just wants to hold the round shank nice and concentric.

                Ian
                All of the gear, no idea...

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                • #9
                  Just freehand grind a point on the square drive end. With a little care error will be minimal.

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                  • #10
                    You can get a 5C to ER adapter and use ER collets. ER stands for Extended (grip) Range. ER collets can collapse as much as .030 in many cases. I use my 5C to ER 32 fairly often in the lathe spindle, Spindex, collet blocks, etc., anything that holds a 5C. A 5C collet has a grip range of about .002. The ER collets cover the oddball sizes.
                    Last edited by Toolguy; 04-07-2021, 10:31 AM.
                    Kansas City area

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                    • #11
                      Originally posted by MrWhoopee View Post
                      5c collets are available in whatever decimal size you care to order. Not cheap.
                      https://shophardinge.com/productGrid.aspx?catID=6896

                      edit: or see if the size you need is here
                      https://www.ebay.com/itm/Hardinge-5C...-/174436577890
                      I wasn't aware that Hardinge made them in increments of a thou.
                      That is pretty expensive for one collet. Imaging if you were to buy the whole set ?? it would cost about $80 K. WOW !

                      JL...................

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                      • #12
                        Originally posted by DR View Post
                        Less expensive than a custom collet to hold taps, you can buy tap holding bushings meant for releasing tapping heads. Somma and Boyar-Schultz are two companies that sell them. The ones I have are hardened and ground, 1/2" diameter split on one side with a square to match the tap's square end.

                        Like everything else in tooling these days I suppose they're expensive.

                        You could also buy tap holding bushing like those on my bench hand tappers. Those might be the least expensive since they aren't hardened. The ones I have are 3/4" diameter with a set screw to hold the tap. They also have the broached square in the end.
                        I'll have to look into that. KO Lee made bushings for their tap grinding fixture that fit standard size 5c's but don't think they are available any more.

                        JL.............

                        Comment


                        • #13
                          Originally posted by Ian B View Post
                          Any chance of switching over to ER collets on your tap grinder?

                          Ian
                          I never really had the need for the ER collets. I've always managed to get by with out them. I do have a Jacobs flex collet chuck for my lathe with a full set of collets. They take a wide range of sizes but trying to adapt the chuck which is an LOO mount to my grinders work head would be more trouble than making a couple bushings.

                          JL............

                          Comment


                          • #14
                            Originally posted by Ian B View Post
                            I think he just means a collet with a plain round hole, as he's only sharpening the tap which doesn't take much torque. He just wants to hold the round shank nice and concentric.

                            Ian
                            Yes, just reducing the beveled end of the tap to get a smaller point that will fit into my tap guide.

                            JL............

                            Comment


                            • #15
                              Originally posted by strokersix View Post
                              Just freehand grind a point on the square drive end. With a little care error will be minimal.
                              I doubt that I would ever get it concentric like that.
                              Some of the taps have a pilot hole, that' OK.

                              JL............

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