Results 1 to 7 of 7

Thread: Collet adapters

  1. #1
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default Collet adapters

    A kind person gave me some weird old collets, and two rough Hercus spindle thread holders/adapters (ER25 & ER32).


    Step Description Pic.
    1) The collets They are 24mm diameter. The front looks just like an ER25,
    but the whole collet is much longer - 45mm.

    Taper is 8°, compared to 16° on an ER.
    I eventually found the spec – Q24/16. Grips up to 16mm
    565599.jpg
    2) The holder An ER25 holder is a compromise – even this unfinished
    one which has some extra metal in the taper.

    The nut end of the taper is loose,
    and the tapered section is shorter than these collets,
    but I think it should grip over half of the collet
    IMG_0479.jpg
    3) Taper setup I mounted a collet on a rod (drill) in my chuck,
    and used a dial gauge on the toolpost
    to align the compound slide angle to the collet's taper
    IMG_0481.jpg
    4) Boring A few passes at 4 or 5 thou, and trial fitted a collet.

    It was stuck out too far, so a few more passes.
    Cleaned up with a little grinding stone
    IMG_0482.jpg
    5) Testing Tightened the nut on a collet,
    and used dial gauge to check runout.

    It wasn't good – about 3thou.
    Tightening the nut more got it down to 2 thou.

    Decided it was just these rusty old collets
    IMG_0486.jpg
    6) ER32 Unmount this hacked holder,
    borrowed ER32 collet on rod, align compound to taper,
    ER32 holder on spindle, final machining of the taper.

    TRO much better. About half thou. Same as my spindle
    IMG_0485.jpg
    7) Fiddling Back to the hacked holder. Fitted it more carefully.

    Noticed that the spindle thread is a little loose.

    Padded the flat section with some paper.
    IMG_0484.jpg
    8) Re-machine In its better centred/mounted position on the spindle,
    polished a few micron off the taper.

    Collet is now about a thou TRO
    IMG_0483.jpg


    So, not exactly precision holders, but more accurate than my 3jaw chuck, and totally free!

    (until I buy some ER32s to fit in that holder)

  2. #2
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    I've had a similar problem, 2 different overall lengths and angles in a collet of the same size. Have located the article I did and pasted it here for your reference.
    https://metalworkforums.com/f65/t192...5+COLLET+CHUCK
    HTH
    Kryn
    To grow old is mandatory, growing up is optional.

  3. #3
    Join Date
    Mar 2017
    Location
    Sydney between denial & paranoia
    Posts
    88

    Default

    You could try getting a South Bend adapter for either 3C collets or if your internal taper is big enough like mine 5C collets.

    20171103_125751.jpg

    20171003_171446.jpg

  4. #4
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    1) Is that a school photo of you on the wall above your 260?

    2) Other collet adapter systems would cost money - these were free!



    I have a Hercus 9, so up to 3/4" through the spindle. There are adapters:
    https://littlemachineshop.com/produc...ProductID=2240
    but I'm not sure they would locate well?


    I have thought about simple MT3 collets:


    but I'm not sure they would be much more accurate than what I have.
    A little longer, but only crush and grip from the front?
    (unlike ER or Q24, which sort of crush front and back)

  5. #5
    Join Date
    Mar 2017
    Location
    Sydney between denial & paranoia
    Posts
    88

    Default

    Quote Originally Posted by nigelpearson View Post
    1) Is that a school photo of you on the wall above your 260?

    2) Other collet adapter systems would cost money - these were free!



    I have a Hercus 9, so up to 3/4" through the spindle. There are adapters:
    https://littlemachineshop.com/produc...ProductID=2240
    but I'm not sure they would locate well?


    I have thought about simple MT3 collets:


    but I'm not sure they would be much more accurate than what I have.
    A little longer, but only crush and grip from the front?
    (unlike ER or Q24, which sort of crush front and back)

    That picture is of my younger brother, he was around 13 or 14 years old at the time.

    My adapter has no run-out that I can detect with a fine resolution test indicator. I credit that on account of it being an original South Bend that fits my spindle taper.

    See the info sheets attached for SB spindle specs and other things. I located my spindle configuration which enabled me to know which spindle I had and which spindle adapter was the correct for my lathe.

    Yes, it cost me a 100$ but it turns true.

    Use of Accessories Inside the South Bend Head Stock.pdfForm 924D HandleverCollet Attachment.pdftooling_dimensions_sb_7324.jpg

  6. #6
    Join Date
    Oct 2008
    Location
    Cairns, Q
    Posts
    666

    Default

    Hi Nigel,

    I have metric and imperial sets of these in the common tool shank sizes which I bought years ago for the mill before I got an ER32 chuck. They still have occasional use in the mill, because they are completely swallowed in the spindle's morse taper, so you gain about 40 extra millimetres of working height between the table and the spindle to accommodate larger workpieces.

    They will work in the lathe spindle quite satisfactorily, but they are not really useful for work holding for three reasons.

    1. They will only tighten on material of the nominal size - there is no flexibility as there is with spring collets like the ER series.

    2. They require a drawbar through the headstock spindle to tighten them. This is inconvenient for work holding because the drawbar has to be loosened and the collet tapped loose in the spindle to release the workpiece each time it is changed.

    3. They can only hold short pieces before they hit the drawbar. The ER and similar collet types with the locking nuts at the front allow the workpiece to pass through the collet, and, depending on the chuck design, through the spindle as well, so there is no limit to the workpiece length.

    Frank.

  7. #7
    Join Date
    Mar 2017
    Location
    Sydney between denial & paranoia
    Posts
    88

    Default

    Nigel,

    the other reason I went with the 5C collets is that I can use expanding collets also. For the sort of stuff I have done and want to in the future expanding collets are perfect.



    20180613_201647.jpg

    20180908_203220.jpg

    20180908_203325.jpg

Similar Threads

  1. Wheel adapters for trailers, are they legal in Victoria?
    By Com_VC in forum TRAILERS & OTHER FABRICATED STUFF
    Replies: 10
    Last Post: 10th Apr 2018, 12:19 AM
  2. OT: Metalwork, Automotive bush press adapters
    By .RC. in forum METALWORK GENERAL
    Replies: 11
    Last Post: 12th Oct 2015, 05:27 PM
  3. 2MT v's R8 collet
    By DaveTTC in forum METALWORK GENERAL
    Replies: 4
    Last Post: 11th Apr 2014, 06:50 PM
  4. 5MT - 5C Collet adapters
    By Gavin Newman in forum METALWORK GENERAL
    Replies: 9
    Last Post: 3rd Mar 2010, 09:24 PM
  5. Gas converter adapters
    By DeltaNegative in forum METALWORK GENERAL
    Replies: 4
    Last Post: 29th Jul 2009, 10:04 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •