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School me on 5C vs. ER series, please...

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  • Black_Moons
    replied
    Are there 'fixtures' commonly avilable for ER-xx collets? Or is it only 5C that has so many cheap blocks and such on the market?

    Any other common collet systems that are more in use in the industry?

    Leave a comment:


  • loose nut
    replied
    Originally posted by DICKEYBIRD
    You guys'll never get real rigidity using any wimpy-a$$ed collet setup.

    For a truely macho tool system, do as I do. Each time I need to change tools, I machine a brand new spindle from an aged Billet™ of 4140 Unobtanium®, machine the end to the needed tool shape, heat treat it using Cryogenic Cold-Fusion Induction Hardening®, final grind the flutes with my 7-axis liquid nitrogen cooled diamond wheel CNC grinder and install it back into the spindle using a brand new set of ABEC 9 bearings with the preload adjusted by one of the only 2 qualified Buddhist monk preload setters in the world.

    Then and only then can you say you have a rigid tool setup.
    If you fix the mill in a non-rotating holder mounted on a gantry out side of the floor footings and then rotate the whole shop underneath it, the set up might be more rigid.

    Leave a comment:


  • Clevelander
    replied
    I think it's time for me to back up..

    It's been 10 years since I used the mill that I'm talking about and in retrospect I believe I'm wrong. I believe it was an R8 assembly however the collets close in a way that is similar to the 5C collet where it is basically a "pinched end". In re-reading the whole thread I see that the description I saw made sense, that the ER series are more for tool holding rather than material holding. That said I see it comes with a new challenge of geting the assembly as tight as required.

    Nothing's easy, but I guess if we were looking for easy we'd be doing simple basket weaving instead of machine work.

    Leave a comment:


  • DICKEYBIRD
    replied
    You guys'll never get real rigidity using any wimpy-a$$ed collet setup.

    For a truely macho tool system, do as I do. Each time I need to change tools, I machine a brand new spindle from an aged Billet™ of 4140 Unobtanium®, machine the end to the needed tool shape, heat treat it using Cryogenic Cold-Fusion Induction Hardening®, final grind the flutes with my 7-axis liquid nitrogen cooled diamond wheel CNC grinder and install it back into the spindle using a brand new set of ABEC 9 bearings with the preload adjusted by one of the only 2 qualified Buddhist monk preload setters in the world.

    Then and only then can you say you have a rigid tool setup.

    Leave a comment:


  • justanengineer
    replied
    5c closes at the nose, at nominal, but I would dare say you are more likely to get wobble from the loss of rigidity using an ER than you are from using a properly sized 5c. Many use rules of thumb related to the work sticking out of the chuck, but in many cases you need to consider the total distance from the spindle nose.

    Leave a comment:


  • Black_Moons
    replied
    Originally posted by 1200rpm
    that`s a great point, i`ve wondered about that. i`ve heard anywhere from 50~150 ft/lb ???? is there a torque spec for each individual size or something?
    Yes
    http://bbs.homeshopmachinist.net/showthread.php?t=38649

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  • 1200rpm
    replied
    that`s a great point, i`ve wondered about that. i`ve heard anywhere from 50~150 ft/lb ???? is there a torque spec for each individual size or something?

    Leave a comment:


  • Black_Moons
    replied
    Oh, ER32 and 40 also need IIRC around 100+ ftlbs of torque to tighten fully, So you basicly need a deticated fixture bolted down to something and a 12~18" wrench. Undertightening ER32/40 is a common cause of tool pull out since they require such insane amounts of torque compaired to smaller ER sizes and other collet types in general.

    Are there ER emergency collets?
    Last edited by Black_Moons; 03-09-2012, 06:36 AM.

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  • 1200rpm
    replied
    i haven`t seen anyone mention directly that C types are nose closers and ER types are parallel closers.
    as i have been taught(so take with a grain) C types are the most accurate *at the nominal diameter, at the nose*
    meaning at anything other than the nominal diameter once you get 4 inches out from the collet you could find that it wobbles like mad.

    the ER`s grip in a parallel fashion over the range of the collet so if you are using a 1/2" collet and your piece is .490 ,you`re still good to go. wobble not an issue.
    you may lose a tiny bit of accuracy at the nose but it will hold true 4" out from the collet even if your piece is off-nominal. they grip like a bear too so they are nice for cutting tools.

    both have definate advantages and disadvantages depending on the work being done.

    interested to see if i have been taught correctly??
    Last edited by 1200rpm; 03-09-2012, 05:46 AM.

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  • Mcgyver
    replied
    what machine do you have where you're holding a cutter in 5c collets? and btw the 5c only holds like that if the piece is way off nominal. If you're holding a .499 stock in a .500 collet it will be rock solid

    Leave a comment:


  • Clevelander
    replied
    So, Here's my question...

    My impression is that there were a couple of real advantages with the ER style collets (and now's the time for me to find out before I tool up again). I understand the range of holding in a given nominal size is greater and that the holding power is better because the entire body contracts rather than just the "end" of the collet pinching the item being held.

    I ask in particular because it was very frustrating to me when I was making a part to see that tell tale mark in your work that says your cutter has moved out of the collet and just ruined your part.

    Leave a comment:


  • Mcgyver
    replied
    Originally posted by gbritnell
    There are many different manufacturers of 5C collets, likewise ER collets. You would think that by using a collet that your work would run true, not always the case. Some collets are not as accurate as they are listed to be and likewise the chucks that they mount into have varying degrees of accuracy.
    good point, I buy quality brands used and check them...having much runout defeats the point of collets. The best set up I have had was a hardened collet spindle adapter and drawbar, eliminates the chuck and mounting error. With a hardinge collet a tenths indicator would barely flicker

    Leave a comment:


  • gbritnell
    replied
    There are many different manufacturers of 5C collets, likewise ER collets. You would think that by using a collet that your work would run true, not always the case. Some collets are not as accurate as they are listed to be and likewise the chucks that they mount into have varying degrees of accuracy.
    Some fellows have purchased import collets and chucks and say that they are 'very good' while others, including myself, have had mixed success with the whole affair. About the only way you can guarantee accuracy is to buy a set true collet chuck. That will guarantee repeatability but not necessarily accuracy.
    gbritnell

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  • dian
    replied
    so (again), what about the acuracy of 5c collets?

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  • DR
    replied
    In very general terms.......

    5C collets are work holding collets.

    ER collets are tool holding.


    5C collet holders come in hand wheel type closing, lever closing and power closing. The lever and power closing are suited to rapid part changing as in production work. 5C collets come in all sizes up to 6 inches (step collets). Round, square, hex and any other configuration you can think of, including soft to be machined to size.

    When the machine is properly designed for 5C's the collet is back into the spindle so the work does not extend much out from the spindle nose. This adds to the rigidity and accuracy.


    ER collets (to the best of my expedience) only are closed with a nut. Not suited to rapid work changing. The use of ER collets for work holding is a fairly recent thing, mostly in the hobby machinist area. ER collets come in rounds and tap holding with a square at the back to prevent the tap from rotating.

    ER mounts extend the collet out from the spindle nose leading to less rigidity and possibility of runout.

    Leave a comment:

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