# Thread: How to 2D Draw A Tooth of Gear?

1. ## How to 2D Draw A Tooth of Gear?

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Hi,

Could anybody please give me an easy example of how to create a 2D drawing (standard mechanical engineering drawing) of one tooth of gear such as below image?

http://i47.tinypic.com/fbi82g.png

Thank you

2. One way is to get yourself a book that explains the process or look it up on line.

A second option would be to use a custom lisp routine that draws 2D gears, input the required data, let the routine draw the complete gear, take what you need and erase the remainder.

This was ridiculously easy to find...http://www.cartertools.com/involute.html

3. Metric or inch?
Are you willing to work through the entire process - beginning to end (read, not so easy)?
What textbook are you using?
Do you have a specific size?
Information like
# of teeth?
pitch?

Do you have MS Excel?

4. Originally Posted by JD Mather
Metric or inch?
Are you willing to work through the entire process - beginning to end (read, not so easy)?
What textbook are you using?
Do you have a specific size?
Information like
# of teeth?
pitch?

Do you have MS Excel?
Inch.

Yes.

Mechanical Design of Machine Elements and Machines – A Failure Prevention Perspective by Jack A. Collins.

No.

Just the one.

Any.

Yes I have.

Just the one.
I understand that you only want to draw one tooth, but in order to draw that one tooth you must know how many total teeth are on the gear.

There are two ways to draw the gear (tooth), the more complex involute curve and a simplified representation using the Wellman's Odontograph method.

I will start with the Wellman's technique and make up parameters since you don't seem to have any starting information.
Let me go find my spreadsheet.

6. I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.
Once I know you are following along OK, then I will post the spreadsheet.

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).
Attach your dwg file of what you have completed so far.

Gear Start.jpg

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.

7. Originally Posted by JD Mather
I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.
Once I know you are following along OK, then I will post the spreadsheet.

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).
Attach your dwg file of what you have completed so far.

Attachment 39367

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.

Next I will attached the .dwg file.

8. Originally Posted by JD Mather
I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.
Once I know you are following along OK, then I will post the spreadsheet.

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).
Attach your dwg file of what you have completed so far.

Attachment 39367

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.
This is the .dwg file.

You have exploded dimensions - a sure way to fail my class.

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Draw these two red lines at 20° angle and then draw red circle tangent to the angled line.
pressure angle.jpg

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