Need Help! Which Fastening Scheme Is Stronger?


Results 1 to 4 of 4

Thread: Which Fastening Scheme Is Stronger?

  1. #1
    Registered
    Join Date
    Jun 2017
    Posts
    2
    Downloads
    0
    Uploads
    0

    Question Which Fastening Scheme Is Stronger?

    Hello. I am a software engineer by trade and a diesel mechanic by fate. As such, I apologize for asking what may likely be answerable by a first-year mechanical engineering student.

    I have a bus. The bus has support ribs:



    I wish to attach a second story to these support ribs, above the roof:



    Unlike the bare bolts in the photograph above, support columns I add for my second story will have between them and the bus wall (the support ribs) spacer columns. I am unable to determine the best fastening scheme involving these columns, with concern to strength and resilience to road conditions. Will you please help me? I propose two fastening schemes below. Scheme A uses two long bolts through concentric holes, while Scheme B uses four short bolts. Which scheme is stronger and more resilient?

    Which Fastening Scheme Is Stronger?-3-fastening-schemes-jpg

    Thank you for whatever thoughts you share.

    Similar Threads:
    Attached Thumbnails Attached Thumbnails Which Fastening Scheme Is Stronger?-1-bus-support-ribs-jpg   Which Fastening Scheme Is Stronger?-2-second-story-jpg   Which Fastening Scheme Is Stronger?-3-fastening-schemes-jpg  
    Last edited by TheBusDriver; 06-23-2017 at 03:34 PM. Reason: Better drawing.


  2. #2
    Member
    Join Date
    Feb 2008
    Location
    United Kingdom
    Posts
    521
    Downloads
    2
    Uploads
    0

    Default Re: Which Fastening Scheme Is Stronger?

    Both achieve the same result although with considerable differences! The first is quick, easy and less critical on accuracy also simple fabrication although weather penetration could be an issue!
    The second is far more complicated requiring accurate drilling and tapping of both legs / body and spacer but could have decent weather proofing!
    Personally i'd go with the first!



  3. #3
    Registered
    Join Date
    Jun 2017
    Posts
    2
    Downloads
    0
    Uploads
    0

    Default Re: Which Fastening Scheme Is Stronger?

    Thank you for the reply. You answer interests me, as it is not what I was expecting.

    I do not plan on tapping, as I plan on using bolts (with non-threaded body sections bearing tube wall loads, likely with spacers on nut ends). In terms of structural integrity, however, would you say that Schemes A and B are more or less equal? Roads can be harsh. I expect a good deal of vertical shear.



  4. #4
    Member
    Join Date
    Feb 2008
    Location
    United Kingdom
    Posts
    521
    Downloads
    2
    Uploads
    0

    Default Re: Which Fastening Scheme Is Stronger?

    Quote Originally Posted by TheBusDriver View Post
    Thank you for the reply. You answer interests me, as it is not what I was expecting.

    I do not plan on tapping, as I plan on using bolts (with non-threaded body sections bearing tube wall loads, likely with spacers on nut ends). In terms of structural integrity, however, would you say that Schemes A and B are more or less equal? Roads can be harsh. I expect a good deal of vertical shear.
    If you are concerned with rough roads / vertical shear then clamped surface area is your friend! In the bus pic above the small dowel like spacers provide little clamping area but if you used, say, a 3" sq plate welded to the leg and bolted through that and the body at 4 corners you have considerable loading capacity compared!



Tags for this Thread

Posting Permissions

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


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Which Fastening Scheme Is Stronger?

Which Fastening Scheme Is Stronger?