# Thread: How to draw a 2D Spring ?

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Originally Posted by autocat

Attachment 32119
You're very welcome. If I am not mistaken, it looks strangely like a helix of exactly 3 turns, wound in a counter-clockwise direction, with overall height of 12, and radius of 3. But then, why wouldn't it? Isn't that what you requested?

Now for the fun part.

In order to help you visualize and understand what is happening, leave it in this view, for the following sequence.

Redo all of your previous steps, but this time substitute in the actual dimension values that you are meant to use.

If the spring is wound from 8mm wire, and has ID of 22 mm then your helix diameter will need to be 30mm in order to represent the centerline of the wire.

After you have got the helix done, draw a circle with diameter of 8mm.

Then read about the SWEEP command, or just enter SWEEP in your commandline and take a shot at it. Your goal is to SWEEP the 8mm diameter circle along the helix (path). If you succeed, you will have modeled in 3 dimensions the spring which you need to represent in your 2D drawing.

Post back here with an update, we are all pulling for you.

2. I am abit confused on the measurement of the spring.. I believe you get 30mm from ID of 22+8mm of wire. So this 30mm is for Specify base radius or Specify top radius?

Attachment 32126

Anyway i have created the spring with a
Specify base radius or [Diameter] <3.0000>: 30
Specify top radius or [Diameter] <3.0000>: 30
Specify helix height or [Axis endpoint/Turns/turn Height/tWist] <1.0000>: 3

Then i drew a circle of 8mm and try to use the sweep command. First i clicked on the 8mm circle, then i clicked on the spring. But the command bar says unable to sweep 1 selected objects.

Am i doing it wrong?

3. I am actually thinking is Specify helix height or [Axis endpoint/Turns/turn Height/tWist] this command here is actually asking how long the length of the wire is which is 8mm?

4. Originally Posted by autocat
I am actually thinking is Specify helix height or [Axis endpoint/Turns/turn Height/tWist] this command here is actually asking how long the length of the wire is which is 8mm?
The length of the wire is unknown, and that is fine. You can describe the other known attributes which define the size and characteristics of the spring. You can use specify the helix height, which is the default value. If you use it, then the assumption is that you want the spring to go straight up at 90 degrees. You can get the same result by drawing a line to identify the axis endpoint which is perpendicular to the base and of the appropriate length, but don't bother, just use the default HELIX HEIGHT (but you must designate the value for it). You might use the other option, Axis endpoint, if you wanted to make a spring off axis.

make a copy of the helix with which you are playing around, so that you can easily explore the results of the numerous options. Don't worry about screwing something up, you can always use the UNDO command to go back to the point before you got lead astray. Experiment, it is a great way to learn.

If you are making a spring of 3 turns, then your helix height will obviously need to be at least 3 times the height of a single turn, which cannot be less than the diameter of the wire. Clearly the height of your helix cannot be 3. Try making it a number which is larger than 3x8 (the diameter of the wire), as if it is smaller than that clearly when you try to wind the spring (sweeping it along the helix), it is going to be a problem. Try using helix height of 72, with 3 turns.

Unless you are trying to make a tapered non-cylindrical spring then your helix base diameter and top diameter will need to be the same, in this case 30.

You may recall this excerpt from JD Mather's posting?
The inside diameter (ID) is the largest CYLINDER that would fit through the center of the spring.

5. sweep.jpg

Specify base radius or [Diameter] <3.0000>: 30
Specify top radius or [Diameter] <3.0000>: 30
Specify helix height or [Axis endpoint/Turns/turn Height/tWist] <1.0000>: 72

Small circle diameter:8

Enter sweep command, another small circle pop up -.-

6. Oh good, you are still around, that makes this much more gratifying for me. You do not need to align the circle which you made to the helix, the program should take care of that for you. If you do choose to specify the base point for the circle, you should choose the center of the circle.

7. Yea.. I'm always here but i wonder what had happened to ReMark...

Oh really... cause i watched it from a youtube video ... let me go try again

8. How do i choose the base point of the circle? when i typed in sweep, I can only choose either the circle or the spring, the whole thing is just highlighted when i mouseover.

I also tried to create a circle besides the spring, but still the same problem, 2 circles appearing.

9. Originally Posted by autocat
How do i choose the base point of the circle? when i typed in sweep, I can only choose either the circle or the spring, the whole thing is just highlighted when i mouseover.

I also tried to create a circle besides the spring, but still the same problem, 2 circles appearing.
Do you have your OSNAPS turned on? In your OSNAP settings check CENTER. Then click on it and you should see the CENTER point snap displayed.

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Here is some further recommended reading ............. all obtained by pressing the f1 button and entering relevant search terms HELIX and SWEEP.

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