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1" 5 C Collet ???

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  • 1" 5 C Collet ???

    For the first time today I broke out my new Lyndex 1" R8 collet that I bought new quite some time ago to complete my set.
    I was going to use it on a new Niagara 1 3/16" end mill. I never liked the idea of a 1" R8 because it extends below the spindle taper.
    But here's why I didn't use it....
    First thing I didn't like is that it is only 3/4" deep, not a lot to hold on to when the endmill is close to 5" long. When I started tightening up the draw bar it felt like I wasn't tightening anything, just couldn't get to that snug feel. I got the feeling that if I continued to tighten I was going to snap the exposed end of the collet finger. After it felt somewhat snug, but not tight, I gently grabbed the end mill to get a feel for how secure it might be and I could feel it wiggle.
    I knew exactly what was happening, the fingers were spreading and and not making full or parallel contact around the shank. So I couldn't use it. I measured the ID of the collet and it measured 1.014" I thought that was a bit too big since every collet I have I can slip the cutter in it and it usually doesn't fall out. Perhaps this one is defective????


    JL.................
    Last edited by JoeLee; 04-22-2017, 09:55 PM.

  • #2
    It's my understanding that in the 5C world, a 1 inch collet is only for 1 inch work or 1 inch tools. The have a very narrow range where they grip properly.

    If you look at http://www.lyndexnikken.com/5C-Round...INCH-c1232.htm you will see that they come in 1/32 steps. You can also get them in 64ths.

    Dan
    Last edited by danlb; 04-22-2017, 08:57 PM.
    At the end of the project, there is a profound difference between spare parts and left over parts.

    Location: SF East Bay.

    Comment


    • #3
      Hi,

      Are you talking about an R8 collet? 5Cs generally aren't used for tool holding. And a 5c collet would fit entirely in a 5c chuck.

      1" R8s are the dumbest thing ever. Who ever thought that one up should have been thoroughly beaten about the head and neck.

      As much as I often disparage endmill holders, this is where you need one.

      Dalee
      If you think you understand what is going on, you haven't been paying attention.

      Comment


      • #4
        "Perhaps this one is defective????"

        Yes it is....when you speak of 5C collets the words "Lyndex" and "defective" can be used interchangeably. Several times I've had to buy Lyndex 5C's locally when we were in a pinch needing an extra of a certain size. They're absolute junk for production work.

        A few points..... To measure a collet you would have to have it partially closed in its spindle taper with the faces perfectly parallel. Even Hardinge 1" collets only have 3/4" long grip surfaces, I believe some other quality collets have longer grip faces. At one time Hardinge made special 5C collets with four slots and longer grip faces intended for difficult gripping situations (like holding tool shanks).

        Comment


        • #5
          What type of machine are you using this 5C collet in, and how did you measure the id? It's possible for the id to measure oversize if the collet is sprung open but even at that, 0.014 seems a bit much. As for the 3/4 depth, that is an indication of a defective collet, or maybe it's something other than a 5C, as the 5C has an ID big enough to clear 1 1/16" through the whole collet.

          Comment


          • #6
            JoeLee, I'm going to assume that endmill has a 1" shank. A 1" shaft should pass completely through a 5C collet (I do pass-through the headstock with 1" regularly). Regarding the length of grip, it is pointless to extend the grip much because of the short length of compression taper on a 5C. What's the point of longer grip-length if you don't have any way of squeezing it?

            If that endmill has a 1-3/16 shank, well, I don't know how you got it in there! If somehow you did without breaking the collet, that is why it wouldn't seat properly.
            Last edited by chipmaker4130; 04-22-2017, 09:50 PM.
            Southwest Utah

            Comment


            • #7
              Sorry guys........ I really messed this one up........I meant R8 not 5C. I edited my OP.
              And yes, the 1 3/16" end mill does have a 1" shank. I also measured it and it's 1.000

              JL...................
              Last edited by JoeLee; 04-22-2017, 10:19 PM.

              Comment


              • #8
                Originally posted by JoeLee View Post
                Sorry guys........ I really messed this one up........I meant R8 not 5C. I edited my OP.

                JL...................
                My first post still applies. For optimum clamping, the piece you are holding should be within a few thousandths of the size of the collet. Jamming a larger part into the collet will spring it and will not hold well.

                Dan
                At the end of the project, there is a profound difference between spare parts and left over parts.

                Location: SF East Bay.

                Comment


                • #9
                  1" R8 collets are available. They should not be. Others who posted explained why, and quite eloquently. 7/8" is the largest that is useful but haqs a short bore so it will not stand up to heavy cuts.

                  Comment


                  • #10
                    Originally posted by danlb View Post
                    My first post still applies. For optimum clamping, the piece you are holding should be within a few thousandths of the size of the collet. Jamming a larger part into the collet will spring it and will not hold well.

                    Dan
                    Yes, I understand this completely, collets have a gripping range. Anything over or under results in point contact. The collet measured 1.014. I'm certainly not jamming the 1" shank into that oversize hole. When it closes up I'm guessing it's biting on the end.

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

                    Comment


                    • #11
                      Sorry. Your first post said you were using a 1 3/16" end mill and did not say that it had a reduced shank. Ignore my posts.
                      At the end of the project, there is a profound difference between spare parts and left over parts.

                      Location: SF East Bay.

                      Comment


                      • #12
                        If you need to hold a 1" shank end mill in an R8 spindle it would be much better to use a solid bore end mill holder rather than that spit collet. Especially where you're going too use a 1 3/16" end mill.

                        Comment


                        • #13
                          The easiest thing to is to grind the 1" shank down to 7/8" or better yet 3/4" which I can do. The end mill has center marks on each end.

                          And your right...... there shouldn't even be a 1" R 8.

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

                          Comment


                          • #14
                            Here is a picture of the collet and end mill.
                            You can see through the slit that the collet shank seats at the start of the taper, 3/4" which leaves 3 3/4" of cutter hanging out.
                            No way this can work safely or accurately.
                            The collet opening measures 1.014 as it sits there. How else would you measure it not knowing where it's supposed to seat??
                            Either way, it's just going to spread when tightened. I don't know what the thought was when Lyndex was making these??

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



                            Comment


                            • #15
                              Originally posted by JoeLee View Post
                              Here is a picture of the collet and end mill.
                              You can see through the slit that the collet shank seats at the start of the taper, 3/4" which leaves 3 3/4" of cutter hanging out.
                              No way this can work safely or accurately.
                              The collet opening measures 1.014 as it sits there. How else would you measure it not knowing where it's supposed to seat??
                              Either way, it's just going to spread when tightened. I don't know what the thought was when Lyndex was making these??

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



                              Take the holder and throw it in the scrap. I tried using one of those adapters and it broke in two while I was using it to hold a long one inch endmill to mill a pocket jn an awkwardly shaped part. Regards David Powell.

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