Sizing Roll Pin Holes
Largest Manufacturing Technology
Community On The Web
Close
Login to Your Account

Results 1 to 17 of 17
  1. #1
    Join Date
    Dec 2008
    Location
    miami florida
    Posts
    48
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default Sizing Roll Pin Holes

    Is there any standard in machinists handbooks for determining the correct drill size in relation to roll pin diameter when drilling the holes? Thanks in advance for any help given.

  2. #2
    Join Date
    Apr 2008
    Location
    Troy, NY
    Posts
    472
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    55

    Default

    I'm not sure of any rule, but making the hole .020" under per inch diameter has always worked for me. Usually I work with roll pins up to .250" dia.

    Just checked MH, and it gives no info on roll pins (at least my 1940s ed.)

  3. #3
    Join Date
    Nov 2005
    Location
    Maryland
    Posts
    8,380
    Post Thanks / Like
    Likes (Given)
    741
    Likes (Received)
    969

    Default

    Roll pins are sized by the diameter of the required hole, i.e. a 1/8" roll pin will fit tightly in a 1/8" hole.

    No calculation required.

    - Leigh

  4. Likes Limy Sami liked this post
  5. #4
    Join Date
    Jun 2007
    Location
    New Zealand
    Posts
    2,661
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    23

    Default

    Hmmm - my understanding was that the pins were made to fit holes at the standard nominal size, ie the pins are oversize in the relaxed state.

    I checked my Unbrako Sel-Loc literature, and it confirms this.
    The recommended hole size for a 1/4" pin is 0.250 - 0.256"
    for 1/8" pin it's 0.125 - 0.129"

    (PS: while I was writing and checking this, Leigh typed the same thing more succinctly)

  6. #5
    Join Date
    Nov 2005
    Location
    Maryland
    Posts
    8,380
    Post Thanks / Like
    Likes (Given)
    741
    Likes (Received)
    969

    Default

    Quote Originally Posted by Troup View Post
    (PS: while I was writing and checking this, Leigh typed the same thing more succinctly)
    Brevity is the essence of something.

    See, we do agree occasionally.

    - Leigh

  7. #6
    Join Date
    Sep 2006
    Location
    SE PA, Philly
    Posts
    4,884
    Post Thanks / Like
    Likes (Given)
    833
    Likes (Received)
    1432

    Default

    "Brevity is the soul of wit"

    Lord Polonius, Hamlet, Wm. Shakespeare

    Glad everyone agrees this time.

    Jim

    This business is well ended.
    My liege, and madam, to expostulate
    What majesty should be, what duty is,
    Why day is day, night night, and time is time,
    Were nothing but to waste night, day and time.
    Therefore, since brevity is the soul of wit,
    And tediousness the limbs and outward flourishes,
    I will be brief: your noble son is mad:
    Mad call I it; for, to define true madness,
    What is't but to be nothing else but mad?
    But let that go.

  8. #7
    Join Date
    Nov 2005
    Location
    Maryland
    Posts
    8,380
    Post Thanks / Like
    Likes (Given)
    741
    Likes (Received)
    969

    Unhappy for shame

    Quote Originally Posted by bosleyjr View Post
    Lord Polonius, Hamlet, Wm. Shakespeare
    Hmmm...

    That I should elicit a quote from Shakespeare is a shame I shall carry to my grave.

    - Leigh

  9. #8
    Join Date
    Feb 2007
    Location
    upton ma
    Posts
    1,627
    Post Thanks / Like
    Likes (Given)
    42
    Likes (Received)
    158

    Default

    Leigh has it right, I remember this one clearly from early in my career.

    Pardon the digression;
    I was a ME at a well known co designing a supercomputer. My boss had an outside consultant design the door extrusions. The doors were designed to pivot on roll pins. I had no part in the design and my boss took a vaction when the parts were supposed to come in and had me check on them. Well the consultant undersized the holes - never bothered to look up the design data for roll pins. I figured out the problem and obviously all the prototypes had to be reworked to fit. Somehow the design error became my fault
    Left there within 6 months - they never succeeded in the supercomputer business.

    Paul

  10. Likes 110octane liked this post
  11. #9
    Join Date
    Apr 2008
    Location
    Troy, NY
    Posts
    472
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    55

    Default

    Quote Originally Posted by register View Post
    I'm not sure of any rule, but making the hole .020" under per inch diameter has always worked for me. Usually I work with roll pins up to .250" dia.

    Just checked MH, and it gives no info on roll pins (at least my 1940s ed.)
    You know, I was wondering why it was always so difficult to put roll pins in the undersize holes. I mean, it worked... but it always took some real elbow grease.

    Thanks for the lesson.

  12. #10
    Join Date
    Dec 2008
    Location
    miami florida
    Posts
    48
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Thanks for your reply. I just spent $40.00 on a 5/8 shaft for my DoAll and needed this info before drilling.

  13. #11
    Join Date
    Dec 2012
    Location
    Alabama USA
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    1

    Default Roll Pin Data

    We can make it official. As stated by the real Leigh,the nominal size is the drill size. If the site will allow links, here is a published table:

    Spring Pins, Roll Pins, Split Pins Size Table ANSI/ASME B18.8.2 | Engineers Edge

  14. Likes extropic liked this post
  15. #12
    Join Date
    Dec 2008
    Country
    UNITED STATES
    State/Province
    New York
    Posts
    5,763
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1496

    Default

    take roll pin and use a drill bit gage plate the ones with holes drilled in a plate to quickly find drill bit size
    .
    usually .250 roll pin needs .265 hole to go in by hand. not sure exact size but the definitely are bigger than stated size and they compress smaller to go in a hole
    .
    drill bit gage plate - Google Search

  16. #13
    Join Date
    Nov 2003
    Location
    Beaumont, TX, USA
    Posts
    3,296
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    749

    Default

    That's what I always thought. But you must be flexible. If the nominal size drill does not work, then adjust as needed.



    Quote Originally Posted by The real Leigh View Post
    Roll pins are sized by the diameter of the required hole, i.e. a 1/8" roll pin will fit tightly in a 1/8" hole.

    No calculation required.

    - Leigh

  17. #14
    Join Date
    Nov 2003
    Location
    Beaumont, TX, USA
    Posts
    3,296
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    749

    Default

    But the whole idea of a roll pin, a spring pin is that it is deliberately a bit oversized and it will shrink to size as it is inserted in the nominal size hole. Thus some force is needed to insert one. The ends of the roll pins are tapered for a short distance to facilitate the insertion. This ensures a tight fit but it can be easily removed and reinserted many times.

    It also allows the holes to be slightly different in diameter and the pins will still function as intended. Thus, you can just use common drills. Reamers are not needed.



    Quote Originally Posted by DMF_TomB View Post
    take roll pin and use a drill bit gage plate the ones with holes drilled in a plate to quickly find drill bit size
    .
    usually .250 roll pin needs .265 hole to go in by hand. not sure exact size but the definitely are bigger than stated size and they compress smaller to go in a hole
    .
    drill bit gage plate - Google Search

  18. #15
    Join Date
    Sep 2007
    Location
    Northern Illinois
    Posts
    2,603
    Post Thanks / Like
    Likes (Given)
    692
    Likes (Received)
    1172

    Default

    Yeah, I got caught by this too. About a week before Christmas, the boss says he wants to help out a neighbor... a glass shelf in the cabinet that housed her ceramic figurine collection had collapsed, jamming the doors, and it took hours for her daughter, the only one with arms small enough to fish the figurines out through the small amount they could open the door, to clear the wreckage. A postmortem determined that while the glass shelves could handle the load without deflection, the crappy shelf clips had failed. I suggested he replace them with stainless dowel pins, and to keep from wrecking the wood veneer with pins that would stick in the holes, I suggested we order 6mm dowels (.236" dia.) At the last minute, someone noticed that stainless roll pins were considerably cheaper than dowels, and substituted them on the order. Well, damned, can you believe a 6mm roll pin is larger than 1/4"? About .257" dia or so. This is now the DAY BEFORE CHRISTMAS EVE, and I still need to source four dozen 6mm dowels. Luckily McMaster had them in stock, but I am NEVER going to forget that roll pins are larger than their nominal size.

    Dennis

  19. #16
    Join Date
    Dec 2008
    Country
    UNITED STATES
    State/Province
    New York
    Posts
    5,763
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1496

    Default

    Quote Originally Posted by Modelman View Post
    Yeah, I got caught by this too. About a week before Christmas, the boss says he wants to help out a neighbor... a glass shelf in the cabinet that housed her ceramic figurine collection had collapsed, jamming the doors, and it took hours for her daughter, the only one with arms small enough to fish the figurines out through the small amount they could open the door, to clear the wreckage. A postmortem determined that while the glass shelves could handle the load without deflection, the crappy shelf clips had failed. I suggested he replace them with stainless dowel pins, and to keep from wrecking the wood veneer with pins that would stick in the holes, I suggested we order 6mm dowels (.236" dia.) At the last minute, someone noticed that stainless roll pins were considerably cheaper than dowels, and substituted them on the order. Well, damned, can you believe a 6mm roll pin is larger than 1/4"? About .257" dia or so. This is now the DAY BEFORE CHRISTMAS EVE, and I still need to source four dozen 6mm dowels. Luckily McMaster had them in stock, but I am NEVER going to forget that roll pins are larger than their nominal size.

    Dennis
    .
    .
    usually roll pin is about .010 to .015 bigger. i suspect you got 1/4" instead of 6mm roll pins. happens quite often person filling order puts wrong stuff in the bag. i have even seem stuff in box from China and the mistake happened in China even though shipped from a USA industrial supply company. big industrial suppliers rarely check stuff. they just ship out stuff taking what is printed on label as correct

  20. #17
    Join Date
    May 2003
    Country
    UNITED STATES
    State/Province
    Iowa
    Posts
    9,292
    Post Thanks / Like
    Likes (Given)
    2408
    Likes (Received)
    3072

    Default

    Quote Originally Posted by 110octane View Post
    We can make it official.
    It already was official. You didn't need to open up a 7 year old thread to do that! I'm guessing that ol' Angus finished that job by now.
    JR


Bookmarks

Posting Permissions

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