Results 1 to 12 of 12
  1. #1
    Join Date
    Sep 2011
    Location
    Emerald Central Qld
    Posts
    349

    Default Boring Bar holders for 25mm bars

    Has anyone used a boring bar holder which allows the use of a bar with a dia of 25mm or greater in a lathe which was originally using 16-19 mm tooling ?

    This is for use in a four sided tool post or at a pinch in a quickchange .

    I recently saw Keith Fenner using one when he bored the hub of the fan he made recently.

    Michael

  2. #2
    Join Date
    Mar 2008
    Location
    nowra
    Posts
    1,598

    Default

    At work we have a 50 mm bar goes alright in the old nuttal lathe. Its a 25mm toolpost but same principal.
    Attached Images Attached Images
    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    Andre

  3. #3
    Join Date
    Sep 2011
    Location
    Emerald Central Qld
    Posts
    349

    Default

    That is exactly what I meant , I may just have to make my own as all of the "machinery suppliers" dont seem to be able to supply one that can be used in multiple different capacity lathes .

    They want to sell one for each machine and all will need some changes to be suitable for the intended work.

    Michael

  4. #4
    Join Date
    May 2006
    Location
    Canley Heights, NSW
    Age
    67
    Posts
    529

    Default

    Quote Originally Posted by welder View Post
    At work we have a 50 mm bar goes alright in the old nuttal lathe. Its a 25mm toolpost but same principal.
    Might be wrong, but doesn't look like a very rigid setup.
    Shane

    Got the square peg in the round hole, now can't get it out !!

  5. #5
    Join Date
    Mar 2008
    Location
    nowra
    Posts
    1,598

    Default

    Quote Originally Posted by Auskart View Post
    Might be wrong, but doesn't look like a very rigid setup.
    Your right it isn't the MOST rigid of set ups but that forging is about the maximum size for the lathe.
    you can feel the carriage shake rattle and move but it does a better job than a 25mm bar with the same stickout.
    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    Andre

  6. #6
    Join Date
    Jan 2011
    Location
    Far West Wimmera
    Age
    63
    Posts
    4,049

    Default

    The next step would be to make a new toolpost specifically to hold boring bars. This is one situation where the QCTP is limiting rigidity. Of course if the carriage is moving around it won't make much difference how rigid the toolpost is.

    Dean

  7. #7
    Join Date
    Sep 2011
    Location
    Emerald Central Qld
    Posts
    349

    Default

    The job which I need this setup for is a brake drum of about 12.8 inches ID which has a slight lip from normal wear , its very difficult to fit and remove presently .
    I want to make a main holder to which I can fit split bushes to enable bars to be held from 12mm to 25 mm .

    I also want it not to be machine specific as there are currently two lathes and the HBM and the mill which all need to have boring bars for some work.

    Michael

  8. #8
    Join Date
    Dec 2011
    Location
    Sydney
    Posts
    505

    Default

    Making your own holder is probably the best way to get what you want.
    I have done the same - on a smaller scale - by making a dedicated boring bar toolpost. Start with a suitable size block of steel, face off one end of the block and drill/bore through so it can be clamped to the compound slide with your usual tool post clamping screw. Then it is simple to use drill/ reamer / boring tool in the headstock to through bore the new toolpost to take a boring bar as big as you need.
    Advantages are that the axis of the bar is at centre height, the size of the bar is not constrained by existing toolpost arrangements, and the setup is very rigid with minimal overhangs. Can be sleeved for smaller size bars as you wish.
    This may not ideally meet your requirement for use on different machines, but perhaps could be made for the lathe with least centre height and adapted to the other lathe with a riser block. Not sure about application to a HBM or a mill.
    Cheers,
    Bill

  9. #9
    Join Date
    Aug 2009
    Location
    Lake Macquarie
    Age
    86
    Posts
    90

    Default

    [QUOTE=WCD;1916729]Making your own holder is probably the best way to get what you want.

    I have made a similar Boring Bar holder for my Hercus Craftsman, taking bars from 10mm to 25mm, grooving and other threading tools.
    Also included a Part Off Toolholder.
    Not a QCT but very rigid particularly for the 'white knuckle' part off jobs.

    Col
    DSC00207.JPGDSC00213.JPGDSC00217.JPGDSC00219.JPG

  10. #10
    Join Date
    Jun 2011
    Location
    Australia east coast
    Age
    71
    Posts
    2,713

    Default

    Quote Originally Posted by Mike4 View Post
    I also want it not to be machine specific as there are currently two lathes and the HBM and the mill which all need to have boring bars for some work.

    Michael
    If the boring bar is round, think about holding it in something like an ER32 or ER40 collet. I made such an adaptor up for my Kearns S type HBM. Works fine.

    Won't work for the TCT bars with flattened tops & bottoms though. Could make up some sort of sleeve I suppose but now it's getting too much like a major PITA for any possible gain.

    PDW

  11. #11
    Join Date
    Aug 2015
    Location
    QLD
    Posts
    735

    Default

    Quote Originally Posted by PDW View Post
    If the boring bar is round, think about holding it in something like an ER32 or ER40 collet. I made such an adaptor up for my Kearns S type HBM. Works fine.

    Won't work for the TCT bars with flattened tops & bottoms though. Could make up some sort of sleeve I suppose but now it's getting too much like a major PITA for any possible gain.

    PDW
    Looking at something similar me-self. Use a straight shank ER holder mounted in a larger boring bar holder. US Shop Tools have a range starting page 188.....
    http://www.usshoptools.com/NEW_WEB_2...12_catalog.pdf

  12. #12
    Join Date
    Sep 2011
    Location
    Emerald Central Qld
    Posts
    349

    Default

    Just completed the boring of a 25mm hole in a piece of 50mm bar , tomorrow I will weld a tab on the side and then mill tat flat and parallel to the bore.

    After that several sleeves to make for the smaller bars .

    The 25mm bar that I want to use is as PDW described a round bar with four flats machined on it , it is for gorrving , "o" rings etc.

    Hopefully this will allow more use of my boring bars , instead of them being machine specific.

    Michael

Similar Threads

  1. 5/8 or 16 mm round shank boring bars
    By TED C in forum METALWORK GENERAL
    Replies: 5
    Last Post: 24th Jun 2014, 08:19 PM
  2. Homemade Boring Bars
    By Oldneweng in forum METALWORK GENERAL
    Replies: 19
    Last Post: 6th Sep 2011, 08:11 PM
  3. what are these boring bars used for
    By azzrock in forum METALWORK GENERAL
    Replies: 5
    Last Post: 31st Aug 2011, 07:47 PM
  4. making small boring bars
    By Tiger in forum METALWORK GENERAL
    Replies: 20
    Last Post: 17th May 2010, 11:58 AM
  5. Boring bars
    By Bodgy in forum METALWORK GENERAL
    Replies: 6
    Last Post: 29th Jun 2008, 12:32 PM

Posting Permissions

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