bolts, a bit of useful info

Discussion in 'Tools, Procedures, and Testing trouble shooting' started by grumpyvette, May 20, 2011.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    yes I know you probably never bothered to look and don,t really care UNTIL you start having problems, but it really does help if you understand what the limitations are to fastener strength. and in most cases bolts ARE marked to allow you to at least have some idea as to there limitations



    most experienced mechanics have a 5 gallon bucket of assorted bolts and screws to fall back on when they can,t locate a fastener they break or misplace, youll need to clean used bolts with solvent and a wire brush, but having a bucket of spare fasteners is nearly mandatory, A visit to a local salvage yard with several wrenches and a bucket and a couple hours time, will generally allow you to collect a wide random selection ate a very reasonable price , now you may not find exactly every bolt diameter and length and thread size but you will generally find youve accumulated a good basic selection



    every mechanic should own a decent 12" caliper to measure the length of a bolt,
    that may be missing on any particular application.
    bolts used on any application, must not bottom out in a blind bolt hole if the bolt bottoms out it fails to clamp firmly
    bolts that are not threaded into a blind hole should extend at least two to three times,
    its diameter past the far surface too allow a washer and nut to be threaded onto the bolts extended end to supply clamping force.
    so the depth of the item being clamped and the threaded area the bolt secures its threads too should generally be at least 1/4" deeper than the length of the bolt used,
    and the threads should extend at least 2-3 times the bolt diameter into the threaded area,
    before the bolts clamping force is applied to clamp the item being secured.
    obviously you can get a rough measurement with the base of the caliper.
    and when in doubt select a GRADE #8 fastener,
    as they are significantly stronger than average garden variety hardware store bolts. > Measuring Tools > Calipers&utm_content=56248

    [​IMG] ... vellon.pdf ... alling.pdf ... 2192?print ... vellon.pdf ... chart.aspx
    Last edited by a moderator: Jul 4, 2018
  2. Indycars

    Indycars Administrator Staff Member

    I bought this book several months ago and found it be very interesting and informative. For the price of $14, you can hardly go wrong. ... 993&sr=8-2

    Attached Files:

  3. grumpyvette

    grumpyvette Administrator Staff Member

  4. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  5. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    its amazing how often I've seen guys grab a metric bolt or an SAE bolt and try their damn best to force it into some similar but obviously not matching thread that was never designed to fit it.
    if a bolt won,t easily thread you need to find out why! not grab a breaker bar!

    if you run into problems, don,t grab a bigger hammer or a longer breaker bar THINK THINGS THROUGH!!!

    I was recently asked to figure out why a guy I know could not get his motor mounts to fit correctly, it less that 30 seconds the reason was very obvious,
    he had spend a hour trying to use SAE bolts too screw into METRIC bolt threads!
    only because he was smart enough to ask for help
    was a potentially very costly repair avoided

    Last edited: Aug 18, 2018
  6. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    I like the Thread checker go no go tools Grumpy.
  7. Strictly Attitude

    Strictly Attitude solid fixture here in the forum

    Looks like a handy thing never force it

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