How to Draw a Spiral Ramp in Autocad
- #1
How do you draw a spiral on AutoCad 2000 ???
I need to draw a spiral out to a 4" diameter with a .375" pitch.
Anybody have any info???
Or, if someone can use some other software to do this and e-mail me the DXF that would be awesome.
Thanks In Advance,
Tim
- #2
do a google for 3dspiral.lsp. Load that into your support directory. command is 3dspiral... I think.
Good luck.
- #3
You could try an array of radial lines and then draw (or offset) concentric circles each with a fraction of .375" lager radius than the last. Use the polyline command to construct the spiral and then fit it?
Regards,
Tom
- #4
I'll have to check out the spiral lsp command. One way is to plot a series of points and draw a spline that follows them. The snap to point function works reall well for this. Just make sure you have a straight section leading into the spiral. Now does any one have any idea on how to do a helix?
- #5
Just tried plotting points. I made a polar array (6 lines) and drew concentric circles in .0625" increments, then drew a polyline using the intersections and then fitted it rather than using the spline option. Looks pretty good although I did start at the first circle, .062" from center.
A helix could possibly be generated this way using the 3D polyline command.
Regards,
Tom
RAS
Stainless
- Joined
- Aug 24, 2003
- Location
- PA
- #6
Gee, I hate to say this (I'll probably get flamed), but I did this in BobCad in about ten minutes. The program is looong (about 16,500 lines), but the toolpath looks good. Can AutoCad import '.tap' files? I can save the file in that format...
Btw, I did have to start the toolpath .005 from true center.
RAS
- #7
Gentlemen,
A spiral can be easily defined in polar form. The formula for an increasing spiral starting at zero would be:
R = (Theta/2xPI)x.375
R is the Radius
Theta is the angle in radians
PI = 3.1415927--
And R goes from 0 to RMax
For every revolution, the Radius increases .375.
I suppose one way of doing this would be to do a whole series of straight line approximations (hence the *many* lines of a previous poster).
There is another approximation which one could use, and just how it is implemented depends on the accuracy you need. Basically, it consists of generating (4) offset points about the center, then generating (4) associated arcs, one every 90 degrees, increasing the radius with each 1/4 turn.
Regards,
Jack C.
- #9
Vectorworks has a spiral tool that makes this very easy.
Jim
ps .dxf on the way
- #10
Me too RAS! I have over 2000 lathe programs in
Bobcad and about 20 mill programs.(Thats right..
i barely use the mill) I had upgraded
to ver 19 this morning and i drew the spiral in 2
minutes (another 25 sec for the g-code!)...Dean
- #11
Are we building a scroll chuck?
Paul A.
RAS
Stainless
- Joined
- Aug 24, 2003
- Location
- PA
- #12
dneufell,
I'm using BobCad Ver. 17, and haven't used it for doing anything other than lathe toolpaths. Took me a while to figure out the spiral function, since I don't run the Haas mills at work.
Btw, I see you are a 'newbie' on the forum; welcome! You will be amazed at the amount of help and knowledge available here.
RAS
RAS
Stainless
- Joined
- Aug 24, 2003
- Location
- PA
- #13
Paul,
Hey, thats a good guess; I wonder if that's what Dirt Rider is making...? Seems logical, with the .375 pitch. If so, I hope he posts pictures of the project. I could have included this in my reply to dneufell, but I'm working on getting up to the 'hot rolled' status! 
RAS
- #14
Thanks so much for all the help.
I got exactly what I needed. When the project is done I'll post pics. Maybe even a video.
I'm building a mini kinetic sclupture.
Tim
Source: https://www.practicalmachinist.com/vb/general-archive/autocad-how-draw-phonograph-type-spiral-93530/
0 Response to "How to Draw a Spiral Ramp in Autocad"
Post a Comment