Hi Could anyone of you post here a link to a webpage that actually

  • Context: High School 
  • Thread starter Thread starter dobry_den
  • Start date Start date
  • Tags Tags
    Hi Link
Click For Summary

Discussion Overview

The discussion revolves around understanding how torque applied to a screw translates into a force that drives the screw into a material, specifically focusing on the mechanics of screw motion and the forces involved. The scope includes conceptual explanations and mechanical analysis.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant requests links or explanations regarding how torque on a screw results in axial force, indicating a need for clarity on the mechanics involved.
  • Another participant suggests a Wikipedia page that may contain relevant mechanical analysis related to screws and bolts.
  • A participant proposes a model where the rotation of the screw head leads to a reaction force from the groove in the material, which can be decomposed into two forces, one of which drives the screw into the wood.
  • Another participant expresses uncertainty about the correctness of their drawing and explanation, seeking validation of their reasoning regarding the forces at play.
  • A later reply acknowledges the initial explanation as close but suggests the inclusion of a "normal" force perpendicular to the thread, referencing a simplified analysis of a screw mechanism and providing a formula relating torque to vertical force while noting the simplification of ignoring friction.

Areas of Agreement / Disagreement

Participants express varying degrees of agreement on the mechanics of screw motion, with some validating the proposed ideas while others suggest additional considerations. The discussion remains unresolved regarding the complete accuracy of the explanations and models presented.

Contextual Notes

Some assumptions about friction and the simplifications in the mechanical analysis are noted, but these aspects remain unresolved within the discussion.

dobry_den
Messages
113
Reaction score
0
Hi! Could anyone of you post here a link to a webpage that actually describes how a torque (of a screw) is transformed into a force that acts in the direction of the screw's axis, that makes is to screw in? Or could you briefly explain it? Any help would be highly appreciated.
 
Physics news on Phys.org
I mean like.. what makes the screw to go down, to screw in. After I thought about it, I came up with this idea. When I rotate the "head" of the screw, the shaft (the lower part) rotates as well. Since a part of the shaft is already in the wood (where the thread has made a groove), the groove acts against this rotation - reacting with a force F. This force acts on an inclined plane (the thread) and it is possible to decompose it into two forces, F1 and F2. And it is the force F1 that makes the screw to screw in the wood (see the attached drawing).. Is this the appropriate explanation?
 

Attachments

  • screw.jpg
    screw.jpg
    81.1 KB · Views: 523
dobry_den said:
I mean like.. what makes the screw to go down, to screw in. After I thought about it, I came up with this idea. When I rotate the "head" of the screw, the shaft (the lower part) rotates as well. Since a part of the shaft is already in the wood (where the thread has made a groove), the groove acts against this rotation - reacting with a force F. This force acts on an inclined plane (the thread) and it is possible to decompose it into two forces, F1 and F2. And it is the force F1 that makes the screw to screw in the wood (see the attached drawing).. Is this the appropriate explanation?

inclined plane: http://en.wikipedia.org/wiki/Inclined_plane

helically warped, but that is essentially what a screw is: http://en.wikipedia.org/wiki/Screw
 
Last edited:
Yep, I know, so do you think that my drawing is correct?
 
dobry_den said:
Yep, I know, so do you think that my drawing is correct?

I would say you're pretty close. I think you need the equivalent of a "normal" force that is perpendicular to the angled thread. It gets pretty hard to get your head around the helical screw thread, so I did a quick analysis of a much simpler screw, which consists of a bolt with a small post that acts as the thread and a hole with a helical groove cut in it.

The results of the free body diagram confirm the result you get from a "work balance" analysis:

Fvert = 2*pi*T/d

Where Fvert is the vertical force, T is the applied torque, and d is the thread pitch.

This analysis ignores friction, which is a huge simplification. Hope this helps...
 

Attachments

  • screw.jpg
    screw.jpg
    39.1 KB · Views: 575

Similar threads

High School Hi, I'm learning physics -- Why do things near me not fall toward me?
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad [Questions] Modeling a Baseball Pitch Trajectory in 3D Space
  • · Replies 1 ·
Replies
1
Views
2K
High School Sign conventions in torque and non-uniform circular motion
  • · Replies 1 ·
Replies
1
Views
2K
High School Normal force in case of inclined plane and banked turn
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Drag Coefficient of a 'flexible' object (e.g. a piece of paper)
  • · Replies 4 ·
Replies
4
Views
2K
Considerations for design of lead screw + guide rail set up
  • · Replies 8 ·
Replies
8
Views
4K
High School Pumping water upwards into a large water tank
  • · Replies 6 ·
Replies
6
Views
3K
Graduate Modeling the damping of a physical rigid pendulum
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Does a rotating accelerometer moving linearly measure linear velocity?
  • · Replies 47 ·
2
Replies
47
Views
5K
High School Can a Fire Tornado Flip an 8 Ton Truck?
  • · Replies 5 ·
Replies
5
Views
2K