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ER40 collet chuck for lathe

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  • ER40 collet chuck for lathe

    I have a Jacobs collet chuck and rubber-flex collets, but at times I use them for threaded parts, and if the work ever grabs it can "thread" the collet. The rubber-flex collets are expensive, and not so easy to find, would the ER40 type collet work in a situation like this ? I'm not worried about through spindle capacity with this as I will only be working with 1" length screws, but how much through capacity does a ER40 type collet have ? Work holding ability ? I have seen several threads where people are using the ER type collets on a lathe for work holding. I have a Clausing 4912, 10x36 MT4 spindle so this would be a cheap system

    http://cgi.ebay.com/NEW-ER40-COLLET-...QQcmdZViewItem

  • #2
    The ER series collets are "intended" as tool holding collets, but a collet has no idea what it is holding.

    The lack of surface area on the threaded parts is most likely why they would slip.

    You may get better results with any collet ( 5-C, ER-XX etc.) that has more "gripping" surface area than the rubber-flex collets. If the rubber flex collets you are referencing are the ones with steel "ribs" imbedded in a rubber body that I remember from high school twenty years ago, they have a lot less gripping surface area than almost any other collet.
    Paying Attention Is Not That Expensive.

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    • #3
      Yes they are the rubber-flex with steel ribs. I have not had no problem with gripping power, and they are a great collet, however if the tool bites into the screw the screw will just thread right into the collet causing thread marks. Not starting a which collet is best war, but overall I like the rubber-flex collets best for most work I do, up until this point, and that's because of damage to the collet and the expense of replacing one if you can find one for sale, most are in a partial set or complete set, and of course the seller will not split the set ( I don't blame them). The very best solution would be a 4C collet setup lever operated, but I can't find one I have been looking for a LONG time, nothing in my price range. This is a production type small job I do in my spare time, I'm still new to machine work as well.

      Thanks for the info on the gripping power, I'm pondering wasting a few bucks to see how it will work.

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      • #4
        Yes, they were nice collets to use, though I haven't used a rubberflex collet in twenty years. We liked them because none of our tradeschool lathes had 5-C set ups and they were accurately self-centering and non-marring. Our only other non-marring option was padding the work between the chuck jaws.

        I may have mistaken grip for slip, as you say you are not having a slipping problem.

        The through capacity of the item in the link would be limited as to the through diameter of the MT shank. I'm suspecting it would be fairly small as it appears to be threaded for a drawbar. In this case 5/8-11 or M16. Though hole is probably right around 17/32".

        I know you are not looking to start a collet vs. collet battle and not to "dissuade" you away from ER-XX series collet system in your search for an answer. There are pluses and minuses in every collet system.

        For production, the 5-C collet has the ability to be set-up with an internal work stop that is normally not considered in an ER-XX collet system. The workstop will definately stop any parts from "threading" themselves into the 5-C collet. A workstop will also allow you to repeat facing to length without measuring (once you get one right and do not move the carriage) as long as workpiece diameters are the same. The 5-C doesn't like to open or close much more than about .005" of stated size. Though with a workstop, is easily set-up and used for production. Though if your lathe isn't set-up for 5-C collets wether using a lever operated or handwheel operated closer, equipping for such could become pricey.

        The ER collet series has a lot more "flexability" in that one particular collets size range. Much like the rubberflex collets you are currently using. Though ER-XX series is not intended as workholding, it can be, and, using it as a workholding collet in a production environment, even small scale, may be a bit of a hassle. I'm not sure how easily you could set up a workstop in an ER-XX system, should one be suitable for what you are doing. In addition, changing the parts or tools requires a wrench and the ability to "secure" the spindle. I have no firsthand knowlege of Clausing lathes. Unless your lathe is equipped with a spindle brake, or can easily "secure" the spindle, you may have to drop it into "low range" or back gearing, every time you need to change the part/tool.
        Last edited by ERBenoit; 08-17-2008, 12:11 AM.
        Paying Attention Is Not That Expensive.

        Comment


        • #5
          If it helps and since the stop in the collet holder came up, all of the straight shank ER holders I have from Maritool, have a set screw stop in them, and it doesn't move back like those in a 5C when you clamp down on it, though I've never used them for work holding, only tool holding.

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          • #6
            Originally posted by bobw53
            If it helps and since the stop in the collet holder came up, all of the straight shank ER holders I have from Maritool, have a set screw stop in them,
            The straight shank ER holders that I use (ETM) are threaded also. I also use them for tool holding only. I would think to use as a workstop would require two setscrews, one to jam against the other to prevent the screw serving as the stop from any possibilty of rotating. Or some Loc-tite.

            Originally posted by bobw53
            and it doesn't move back like those in a 5C when you clamp down on it,
            Not sure what you are saying is "moving back when you clamp down on it". The work is pushed or held against the workstop and the collet closed. The work, workstop and collet should move as one complete unit while closing (clamping).
            Last edited by ERBenoit; 08-17-2008, 12:26 AM.
            Paying Attention Is Not That Expensive.

            Comment


            • #7
              Originally posted by ERBenoit
              Not sure what you are saying is "moving back when you clamp down on it". The work is pushed or held against the workstop and the collet closed. The work, workstop and collet should move as one complete unit while closing (clamping).

              That is correct, what I should have said is with a 5C and a stop the stop will move backward Z- (unless a deadstop) at approx 3 times the rate the collet closes. So if length needs to be held close, the diameter better be nuts, or at least less than 1/3rd the tolerance of the length.

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              • #8
                Originally posted by clint
                I'm not worried about through spindle capacity with this as I will only be working with 1" length screws, but how much through capacity does a ER40 type collet have ?
                Backplate mounted ER40 collet chucks are available from Chesters in the UK,

                http://www.chesteruk.net/store/er_la...let_chucks.htm

                their through capacity is at least the same as the maximum collet size. AFAIK they are the only UK supplier, at least to the 'budget' market, offering ER40 in this form though others sell ER32.

                Tim

                Comment


                • #9
                  Originally posted by Timleech
                  Backplate mounted ER40 collet chucks are available from Chesters in the UK,

                  http://www.chesteruk.net/store/er_la...let_chucks.htm

                  their through capacity is at least the same as the maximum collet size. AFAIK they are the only UK supplier, at least to the 'budget' market, offering ER40 in this form though others sell ER32.

                  Tim
                  I have one of these chucks the actual hole is about 28mm and I use it with 26-25mm collets down to 3-2mm collets.

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