ROYMECHX

Screws Fastenings Index


Relevant Tables


Bright Hexagon Screws/Nuts/Washers Cap Screws Strength,torques and Loads Tensile/Yield Strength Bolt Head Clearances Trapezoidal Threads
Screw Stress Areas Bolt Loading ( Preloading etc ) Bolted Joints (Shear Loads etc) Screw Thread Locking systems Studs/ Weldstuds Concrete /wood

Thread dimensions for ISO "medium" class threads 1,6mm to 300mm

Equations & Tables for Screw Thread Tolerance calculations


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Suppliers sites with Screw sizes/Specs
  1. Fuller metric.. Extensive range on DIN/ISO standard screws with dimensions
  2. PTS-UK.. Sizes of various type of Screws
  3. Maryland Metrics..Vast quantity of useful technical information on metric screws in downloadable acrobat pages

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Sites Providing Information On Bolt/Screw Design
  1. Bolt Science..A site dedicated to the Science & Technology of bolted joints
  2. Threaded Fasteners..A Section of the Site DESIGN AND ANALYSIS OF MACHINE ELEMENTS.
  3. Bolted Joints..An informative paper published on the Web
  4. Metric Bolt Strength..Bolt Sizes Strengths- American bias
  5. Croberts Com..Very useful section on the consequence of Bolt Failure
  6. Fastener Design Manual...NASA GRC RP-1228 (9.6 Mbyte pdf file). Design info on bolt + rivet joints
  7. Bolt Council Publications...Guide to Design Criteria for Bolted and Riveted Joints.(6.7 Mbyte pdf file).  Excellent ....
  8. The yielding of fasteners during tightening...An article with surprising conclusions
  9. Keeping It All Together ...Practical notes on bolted joints from an enthuiast
  10. International Thread Standards .. A comprehensive set of thread tables including BSP
  11. Engineering Fundamentals of Threaded Fastener Design and Analysis ..Very detailed and informative downloadable document

Note: on tapping holes:
I normally specify a tapped hole depth of 1.5 dia for a fully threaded hole in a blind tapped hole (steel male and female).
The depth of threaded hole if a plug tap is not used i.e for automatic one stage tapping would be deeper.
According to BS1936 the tapping drill should be have a depth greater than the tapped depth (clearance depth) as follows

Less than M6 = 0.25 x full thread depth...
M6 TO M12 = 0.2 x full thread depth...
Greater than M12 = 0.15 x full thread depth.