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5C vs ER ?

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  • 5C vs ER ?

    I have a 9x20 lathe with a 5C set thru collet chuck. I have a new lathe 13x30 and am considering selling the smaller one. I keep seeing ER collets mentioned in articles and do not understand how they are held and what the advantages are. Any advice or help?
    thanks

  • #2
    An advantage of the ER type collets is that they have a larger holding range. A set of ER-40 for example will provide continuous coverage up to 1" diameter. The drawback is they are typically held in some type of a chuck with solid draw bar, ie no through hole for longer stock. This can be worked around by constructing a spindle/backplate mounted holder. I guess they are mostly for tool holding rather than stock holding, but I do have one that I trade back on forth with on my lathe and mill. I like 'em

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    • #3
      nine views and no replies...I think folks are afraid to touch this as its subject to lots of opinion.

      5C seems to be prevalent in the US, so it means a lot of tooling uses a 5-C spindle making a set of collets a good investment. 5C, however, is a design with the collet split only at one end. As such it does not squeeze parallel on anything other than its nominal size so you really should not use them for anything but the size they are stamped for.

      ER collets suffer from the restriction of bore size (at least in ER-32 which seem to be so common) since 5C are available up to 1-1/8". On the other hand they are split in both directions and are doulbe tapered such that tightening the collet nut will squeeze the collet parallel to its bore and there is more total movement available. Someone else will chime in with the amount of variability in size each collet has, but suffice it to say that they are capable of holding work (or tools) a bit on either side of their nominal size.

      I am keeping my eye out for a bargain on ER-32's and also own a set of 5C's by 32nds since they both have advantages.
      Paul
      Paul Carpenter
      Mapleton, IL

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      • #4
        I have a collet chuck for my Myford Super 7 which fits on the same way as the chucks & so gives a full size through hole for stock, I'm sure this arrangement would be possible with most lathes, I use a collet chuck & drawbar on my milling machines,
        Regards,
        Nick

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        • #5
          Originally posted by pcarpenter
          ER collets suffer from the restriction of bore size (at least in ER-32 which seem to be so common) since 5C are available up to 1-1/8". On the other hand they are split in both directions and are doulbe tapered such that tightening the collet nut will squeeze the collet parallel to its bore and there is more total movement available. Someone else will chime in with the amount of variability in size each collet has, but suffice it to say that they are capable of holding work (or tools) a bit on either side of their nominal size.
          I have and use both 5C and ER-40 chucks in my shop. Paul covered most of the key points, but to elaborate on one issue: ER collets have their minimum runout at the nominal size, and the runout spec increases the further the collet clamps away from the nominal size. For Americans, that ends up being a double-whammy, because ER collets are made to metric dimensions, so the "3/4" ER collet is actually a 19-20mm collet, with nominal runout at 19.5mm = .77".

          That hasn't been an issue for me in my home shop, but a job shop might want to measure the runout difference.

          The TG ("Tremendous Grip") double-angle collet system is essentially the Americanized version of the ER collet system (I don't know which came first), and the TG collets have their minimum runout at Imperial Dimensions. TG's seem to be less common than ER though, and since they're mostly made by Kennametal et al (i.e., no generics), they tend to be more expensive.

          Bob Campbell just posted a neat TG150 collet chuck he made for his lathe here:

          http://www.practicalmachinist.com/vb...7&postcount=56

          I am keeping my eye out for a bargain on ER-32's and also own a set of 5C's by 32nds since they both have advantages.
          Be careful with bargain ER collets -- a lot of folks have posted about high runout on their $99 ER collet sets. I've been patient enough to pick-off ETM and Rego Fix collets on Ebay, but I hear that Frank Mari's ER collets are very good, and much cheaper.
          Last edited by lazlo; 07-23-2008, 12:14 PM.
          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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          • #6
            I use Maritool (maritool.com) ER-20 collets in my cnc mill and have been very happy with the performance, delivery, and price. Frank is on my list as a good guy and a pleasure to do business with.

            Now for lathe collets, I use 5C and 22J on my Colchester. I use a cheap set of enco collets for grabbing anything that is a little bit nasty and a good set of Royal ones for the nice work. I think that using the ER collets on a lathe is a European thing - not saying that it is bad, just different. There is more than one way to skin a cat, and in the end you still have chili.

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            • #7
              Originally posted by pcarpenter
              I also own a set of 5C's by 32nds since they both have advantages.
              Paul
              I have a set of ER 32's that go from 1mm [ 0.040"] to 20mm [ 0.787" ] in one thou increments

              .
              .

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



              Comment


              • #8
                Originally posted by John Stevenson
                I have a set of ER 32's that go from 1mm [ 0.040"] to 20mm [ 0.787" ] in one thou increments
                That's odd -- my ER-32's go from 1mm to 20mm in 0.07874015748031496062992125984252" increments
                Last edited by lazlo; 07-23-2008, 01:06 PM.
                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                Comment


                • #9
                  Originally posted by lazlo
                  ER collets have their minimum runout at the nominal size, and the runout spec increases the further the collet clamps away from the nominal size. For Americans, that ends up being a double-whammy, because ER collets are made to metric dimensions, so the "3/4" ER collet is actually a 19-20mm collet, with nominal runout at 19.5mm = .77".
                  The imperial ER collet sets that Maritool sell are, according to their website, genuine imperial sizes and not restamped metric sizes. Usual disclaimers.

                  Arc Euro http://www.arceurotrade.co.uk sell a nifty 5C to ER32 adaptor (originally designed by a person well known to these pages) which allows you to use ER32 collets in the headstock with long stock same as a 5C collet.

                  But yes, both 5C and ER have their place.

                  Comment


                  • #10
                    gr8life, I had a similar question and received some good information. You might want to check out this thread
                    http://bbs.homeshopmachinist.net/showthread.php?t=29781

                    Tim

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                    • #11
                      Since it hasn't been mentioned yet:

                      One big difference between double-angle collets (ER) and drawbar type split collets which are split only on one end (5C) is that the ER type collets require enough length of stock into the collet to grip properly, while 5C type collets can grip on very short pieces since it's solid in the back end. This can be an issue in a lathe collet chuck since sometimes you may want to grip on a short piece to work on it (like say a small screw that's only 1/4" long or the like).

                      Sometimes you need to grip and odd-sized piece and sometimes you need to grip a short piece, so overall I guess you need to have both types for lathe chucks. It took me a few years to work it out, but finally I have one of each and I use both of them pretty often depending on what I'm working on.

                      You can make a short plug of the diemeter you need so an ER collet can grip it in the back while it grips a short piece in the front. That's kind of a hassle but it can be done in a pinch. In kind, you can turn a 5C soft "emergency" collet to any size you want within it's range, but that's kind of a hassle too for just a single part - not so bad for a production run.

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                      • #12
                        can you get ER collets in hex, square, rectangular, expansion, emergency, ...?

                        can you get a ER spindex? or other milling fixtures that are available in 5c?

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                        • #13
                          Originally posted by quasi
                          can you get ER collets in hex, square, rectangular, expansion, emergency, ...?
                          Someone reckons you can get square but I have never seen one.
                          Again I have never seen the other types. I can't see how an expansion can work given the front closing nut.

                          Can you get a ER spindex? or other milling fixtures that are available in 5c?
                          Yes you can get a spindex in both ER and 5C but only from the UK, or you can get a 5C to er 32 adaptor for existing 5C setups, again only from the UK.

                          http://www.arceurotrade.co.uk/catalo...px?search=er32

                          This comparison between 5C and ER's often comes up and there is no magic bullet collet system.
                          It depends on many things like legacy tooling [ no point buying ER's if you have shed loads of 5C ]

                          Use of collets, [ again ER isn't any good if you are needed special shapes or internal]

                          Wheri ER does score is for the beginner just starting out as you need less of them for a full set with no gaps and it's probably the only work holding and tool holding system with it's size limits.

                          So one set of collets can equip a lathe and mill and the odd attachment like a spindex.

                          I like the ER system as it fills a need at low cost but having said that for the last month I have been using a series of expanding 5C's that have been turned up to do repetition jobs but that again that's not true home shop work.

                          .
                          .

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



                          Comment


                          • #14
                            Thanks for all the input, think I will stick with 5C. Should I find a deal on flebay for ER's I might give it a try. I like the 5C chuck, it allows you to work close in even with a ball turner.
                            thanks again for all the help

                            Comment


                            • #15
                              You could use a MT3 mount to hold your ER collets, and that would get in the way of using the spindle ID for stock, but the solid drawbar is not used to actually open/close the ER collet.

                              ER collets are pushed in by the cap from the front. The collet has a groove in it that part of the cap rides in so that when you unscrew the cap it retracts the collet freeing the stock/tool.

                              On a lathe you'd buy or make a collet holder that mounts to the spindle via the threaded nose or what ever method used by the lathe to secure a chuck. This of course leaves the spindle ID free to slide stock through.

                              On a milling machine is where you'll see the drawbar system used to retain the collet holder. In this situation it's mostly used to hold cutting tools.

                              Originally posted by sidegrinder
                              An advantage of the ER type collets is that they have a larger holding range. A set of ER-40 for example will provide continuous coverage up to 1" diameter. The drawback is they are typically held in some type of a chuck with solid draw bar, ie no through hole for longer stock. This can be worked around by constructing a spindle/backplate mounted holder. I guess they are mostly for tool holding rather than stock holding, but I do have one that I trade back on forth with on my lathe and mill. I like 'em
                              Brett Jones...

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