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linpwer  
#1 Posted : Thursday, June 28, 2007 7:55:35 PM(UTC)
linpwer

Rank: Junior Member

Joined: 6/28/2007(UTC)
Posts: 5

[FONT="Verdana"]I'm looking for help in making a screw thread on a solid cylinder object.

Thanks,
linpwer[/FONT]
jasonb  
#2 Posted : Friday, June 29, 2007 10:50:07 AM(UTC)
jasonb

Rank: Junior Member

Joined: 2/18/2007(UTC)
Posts: 17

I start with a cylinder a given diameter. Make a helix with the same diameter at the center point long the length of my cylinder. I make a surface profile of the thread. I extrude the profile along the helix. I can adjust the pitch of the helix to work out my thread spacing. The I can resize the thread depth by modifying the associated thread profile.

To finish out a bolt I chamfer the end of the cylinder. I then will do a tapper of the bolt thread by creating a long arch from the end face of the thread to the surface of the cylinder. I select the face of the ending thread and extrude the face profile to along the arch so thread tappers out onto the face of the cylinder.

Hope this helps.
linpwer  
#3 Posted : Saturday, June 30, 2007 11:53:56 AM(UTC)
linpwer

Rank: Junior Member

Joined: 6/28/2007(UTC)
Posts: 5

I must not be doing something right with the thread profile. Everytime I try to sweep or extrude the profile I get an ACIS Error of "The helical sweep results in a self-intersecting body.

:confused:
linpwer  
#4 Posted : Saturday, June 30, 2007 1:09:11 PM(UTC)
linpwer

Rank: Junior Member

Joined: 6/28/2007(UTC)
Posts: 5

I did it. :)

I had to create three helixes all on the same axis as the cylinder.
I first made a helix for the major diameter of the screw thread.
Then a helix with the minor diameter of the screw thead that starts at 1/2 pitch from the start of the first helix.
The third helix is with the major diameter of the screw thread, but starts at the pitch distance from the first helix.

I made a surface with helix 1 and helix 2, then a second surface from helix 2 and helix 3. Next join the two surfaces.

Then subtract the surface from the cylinder, which gave me an internally threaded solid. I made a new solid cylinder and subtracted the internal thread.

I had to make the chamfer on the end of cylinder prior to subtracting the thread material. If tried to chamfer one end of the cylinder after subtracting the tread material, I received an error message.
linpwer  
#5 Posted : Monday, July 9, 2007 8:21:29 AM(UTC)
linpwer

Rank: Junior Member

Joined: 6/28/2007(UTC)
Posts: 5

The method I used to create a screw thread in a cylinder is still not quite right. I seem to get a good render but the result with I select the Model to Sheet is not of much use.:confused: I attached a jpg file of the rednering of the screw thread and a pdf file of the Model to Sheet results.

If someone has a method that also gives a good model to sheet result, that would be great.

Thanks,
File Attachment(s):
M3X0.5Thread_SheetDrawing.pdf (100kb) downloaded 5 time(s).
linpwer attached the following image(s):
M3X0.5Thread.jpg (72kb) downloaded 7 time(s).

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nabed  
#6 Posted : Monday, July 9, 2007 9:12:01 AM(UTC)
nabed

Rank: Member

Joined: 2/18/2007(UTC)
Posts: 98

Try elevating the curves You used for the surfaces.
If that doesn't work try splitting up the solid before using the model to sheet command.

Ciao, Norbert
jlm  
#7 Posted : Monday, July 9, 2007 3:44:08 PM(UTC)
jlm

Rank: Senior Member

Joined: 2/18/2007(UTC)
Posts: 1,240
Man
France
Location: Paris & Frankfurt

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Was thanked: 150 time(s) in 95 post(s)
Hi,
I make a lot of threads and I always use one hellix only and a swept profile.
You can find an example file on the old forum, (I still have issues to attach stuff to this one) :

http://csi-concepts.com/conceptsunli...hp?p=9258#9258

This one is a "negative" screw used to make a threaded bore in a bloc by boolean substract.
I hope it helps,
JL
ttrw  
#8 Posted : Monday, May 19, 2008 3:03:34 AM(UTC)
ttrw

Rank: Senior Member

Joined: 4/1/2007(UTC)
Posts: 1,583

Was thanked: 2 time(s) in 2 post(s)
I've put another helix tutorial here;

http://forum.punchcad.com/showthread.php?t=914

:)
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