fine thread bolts

hoggyrubber
hoggyrubber Expert Adviser
edited November -1 in HUDSON
this may have been answered a million times or just a plain 'ol bonehead question, but after no answers to any of my searches i'm asking anyway. what's with all the fine thread bolts? after stripping parts off the 2 parts cars i have seems about every bolt is fine thread. seems like that would have increased production time a little, what was to gain?

Comments

  • [Deleted User]
    [Deleted User]
    I think that was the norm in the '50s. I restored a 1959 Chevy truck and all the body bolts were fine thread as well.
  • [Deleted User]
    [Deleted User]
    I addition to what Ken said about torque , they can take a tighter bite and not be as prone to loosen as a coarser thread would. Hudson not only made fine thread bolts and screws but add washers to make them even tighter.
  • RL Chilton
    RL Chilton Administrator, Member
    As stated, fine thread bolts are much stronger . . . "the Cadillac of bolts", if you'll pardon the expression. It would behoove you to put same back into your car.
  • hoggyrubber
    hoggyrubber Expert Adviser
    ok, i have been wrong in my thinking for all these years. i thought coarse thread was stronger since the threads were deeper. after some more reading i see they actually have more threads it makes for more contact area and the shank is slightly thicker since the threads don't cut in as much. don't worry, i am saving them all for reuse. thank you all for the info and straightning me out.
  • Browniepetersen
    Browniepetersen Senior Contributor
    The one thing not mentioned is that fine thread bolts seldom (I have not seen any) are found below a grade 5 bolt. As stated, they are stronger, harder and since they tend to rust less they make it a lot better for disassembly. Now, if they would have only used a "J" thread?
  • Aaron D. IL
    Aaron D. IL Senior Contributor
    Part of the reason these cars lasted as well as they did. Lesser fasteners would've worked fine but that's not what they went with.
  • [Deleted User]
    [Deleted User]
    The engine head bolts on my Pacemaker (Deluxe!) don't have washers underneath them. This has been the case since I purchased the car over twenty six years ago (apparently came from the factory like this). And, I even had the head off five years ago and put it back on with either the same bolts or good used ones from Dave Kostansek and NO WASHERS and I've had no leaky gasket issues despite having put on over 5000 miles since.
  • Browniepetersen
    Browniepetersen Senior Contributor
    I am guessing that your head bolts are grade 8 bolts. Properly torqued that is easy to understand.
  • [Deleted User]
    [Deleted User]
    Browniepetersen wrote:
    I am guessing that your head bolts are grade 8 bolts. Properly torqued that is easy to understand.

    I don't know about the grade of bolt, but I religiously followed the torque recommendations from the 1950 Hudson mechanical procedures supplement and performed follow up torqueing of the head bolts based on mileage.
  • esfoder
    esfoder Expert Adviser
    Lots of heavy trucks use fine thread bolts on the running gear mounts.

    As far as the grade 8 being stronger I've seen many applications where a grade 5 would last longer. They can flex without fracture in some applications and live longer.



    Just my 2 cants worth



    Happy thanksgiving!!!!





    Dusty
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