Screw Definition and 135 Threads

A screw and a bolt (see Differentiation between bolt and screw below) are similar types of fastener typically made of metal, and characterized by a helical ridge, known as a male thread (external thread). Screws and bolts are used to fasten materials by the engagement of the screw thread with a similar female thread (internal thread) in the matching part.
Screws are often self-threading (also known as self-tapping) where the thread cuts into the material when the screw is turned, creating an internal thread that helps pull fastened materials together and prevent pull-out. There are many screws for a variety of materials; those commonly fastened by screws include wood, sheet metal, and plastic.

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  1. negitron

    Need a fastener locking mechanism for #8-32 NC screw.

    I have a .380 auto handgun which uses a #8-32 NC cap-head screw to retain the trigger guard. During firing, the mechanical shock of the cycling action serves to rapidly loosen this screw regardless of the torque used to tighten it down. I cannot use a standard star washer because they're...
  2. Saladsamurai

    Solving a Power Screw Question - Get Help Here

    I was reading through some examples in my Design text when I came across this one. This was their solution: I am not sure that I completely follow it. Can someone help shed some light on what's going on here? I am assuming that the specimen to be put under tension goes where the "B"...
  3. B

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  4. C

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  5. G

    Removing Socket Cap Screws With Lok-Tite

    OK, not the usual kind of question posed here, but not entirely off-topic either. Last weekend I was trying to remove a couple of socket cap screws (recessed hexagonal drive) that were installed with lok-tite (thanks to the lawyers). After multiple applications of heat from a propane torch...
  6. E

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  7. K

    Method To Exert a Downwards Force (Force created by screw threads?)

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  8. M

    Magnetic Liquid Screw Propeller

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  9. R

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  10. D

    Linear force transfered from an electric motor to a screw.

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  11. M

    Where to Find 5mm x 30mm Allen Head Thread Forming Screws?

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  12. T

    Is Something Wrong with Avocados?

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  13. M

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  14. rohanprabhu

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  15. S

    Do you guys think this professor is trying to screw me over?

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  16. A

    Calculating Allen Screw Diameter with Parallel Load

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  17. B

    Equations to do with the z distance of a screw helix.

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  18. A

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  19. A

    Is it me being retarded or did ETS screw up again?

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  20. wolram

    Invaluable Tool: Multi Positional Obstructed Screw, Nut, Bolt Starter

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  21. S

    Edge, Screw, and mixed dislocations

    Does anyone have an idea as to the relative abundance of each of these types? Why will one type occur over the other in a given situation? Thanks, -Scott
  22. D

    Optics did my professor screw up?

    Homework Statement A cat is standing 1m in front of a mirror. a virtual image is formed 10.0m behind the mirror. what is the radius of curvature for the mirror? Homework Equations 1/f = (1/do)+(1/di) f=+/-(1/2)*R The Attempt at a Solution (1/1m + 1/10m)^-1 = .909 .909*2 = 1.82...
  23. S

    What is the Relationship Between Linear and Rotational Speed for a Screw?

    Could somebody help me with this? Let’s say I have a screw that is 0.25” dia. I want to screw this screw into the wall. First question: If I turn this screw 2 times around its axis, how far the screw will go into the wall? Second question: If I rotate the screw at 10 RPM what is its linear...
  24. E

    How Do You Calculate the Mass of a Single Screw from Multiple Cup Weights?

    I have been given the masses of 5 cups, each with a different amount of screws inside. 1st cup = 13g 2nd cup = 19g 3rd cup = 8g 4th cup = 26g 5th cup = 38g I need to find the mass of a single screw. I was not given any equations or data besides those masses I have no clue how to approach this...
  25. W

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  26. F

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  27. P

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  28. wolram

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  29. F

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    For 10kN vertical load,I just need some instructions to follow and if someone can provide schemes and more details will be great:))))THANKS!
  30. G

    Screw Gauge Pitch: Length of Main Scale Division?

    In a screw gauge, the pitch is defined as the distance traveled in one rotation. Is it also equal to the length of one main scale division? If the length of one main scale division is not given, then can we take it to be equal to the pitch? Or do we take it as equal to some other default value.
  31. J

    Solving Horizontal Force of Screw on Shelf Bracket

    A shelf bracket is mounted on a vertical wall by a single screw, as shown in Figure P12.59. Neglecting the weight of the bracket, find the horizontal component of the force that the screw exerts on the bracket when an F = 86.0 N vertical force is applied as shown. Ok so we have three...
  32. M

    -did my professor screw up the igan vector? matrices fun weee

    Hello everyone, we found 3 igan values: 1, 2, 3 for the last case: 3 we came out with 0 -1 0 0 -1 0 2 -2 -2 he wrote b = 0, a = c; then said igan vecotr is: 0 1 1 but clearly shoouldn't it be: 1 0 1 ?
  33. S

    How Power Screws Work - Explained with Illustrations

    hi does anyone knows how a power screw works, illustrations would be helpful.. thanks ss
  34. L

    Understanding the Right Handed Screw Rule: A Comprehensive Explanation

    can anybody explain me right handed screw rule
  35. T

    Solar Water Heater: Ideas & Advice for Arizona Residents

    I only use gas for heating water, so I'm considering a solar water heater. It seems dumb not to go solar here in Arizona. I was wondering do any of you have a solar water heater? How do you like it? Do you have any plans on how to build one?
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