Pipe cutting template

[andrew239]

Good Afternoon,

I have 2 pieces of round pipe meeting in a V shape, one of them being cut to sit on the other. I need to make a template so the shop guys can put on the pipe for marking the cut, so if i get the section of pipe modelled in 3D, can i then unroll it to procuce the template ?

[Jack_O'neill]

Couple of questions for ya...are the two pieces of pipe coming in at 90° from each other? Is this a purely mechanical joint that will get welded together like in a guard rail or something? If the answers to these are yes, then all you really need is a carpenter's square. Cut a 90° notch on the end of one of them, place it on the other and weld away. You can make the cut by setting a stop on a chop saw at 45°, then adjust the depth. Clamp it down, cut all the way through, roll the pipe over, cut again, and you are done.

 

If you're doing something else, then let me know and I'll see if I can help you further.

[paulmcz]

Check this out. It deals with the same subject (post #

 

http://www.cadtutor.net/forum/showthread.php?29251-Joining-steel-bars/page2

[andrew239]

The pipes are coming together in a v shape with an included angle of around 20 degrees.

It is pretty much what is shown in the pf1 and pf2 of paulmcz's drawing.

[paulmcz]

If the two pipes form 20° angle, then the cut angle will be 10°

[andrew239]

It is a strange design, i will try to attach a picture of the base of the columns. These things will have a plate on either end, the bottom plate is the column base plate, and the top plate carries the actual columns which are a different size pipe to these base pieces.The yellow and red pipes will be coped to fit onto the magenta and cyan pipes respectively.

[JD Mather]

... can i then unroll it to procuce the template ?

 

Autodesk Inventor will do this.

[andrew239]

Unfortunately we do not have inventor here. I have done courses using inventor and i love it, but no matter how many hints i drop we are still actually working with 2D. Every now and then something comes up that needs a bit of 3D, but my skills are pretty rudimentary as I dont use it often, hence the probably dumb questions.

[paulmcz]

Then, a half of the pipe is to be cut to 10° and the other half to 80°. Make 2 templates with the Pipe-cut.lsp program. One for 10° angle and the other for 80°. Rotate one of them 180° and combine the curves at 1/4 of the template width. See the attachment.

tmplt.dwg

Edited April 7, 2011 by paulmcz

[paulmcz]

....It is pretty much what is shown in the pf1 and pf2 of paulmcz's drawing.

 

Not quite! The pf1 and the pf2 situations show connection of a branch pipe to straight piece of larger diameter pipe. Yours is the case of "pc - program", but you have to combine pipe cutting from two sides, as described in previous post and shown in the drawing.

[andrew239]

this is busting my noodle a little bit. This is the piece i am trying to get the template for. It is off center in 2 axis so it is giving me some trouble.

I am trying to upload the model, but i cant get the file size under 325kb

Here is the drawing

BASE PIECE.dwg

Edited April 11, 2011 by andrew239

[paulmcz]

What exactly will this piece have to fit to? Another pipe? Can you post 3 views 2D drawing of the complete assembly?

[SEANT]

Here’s the work of an early (extremely limited) prototype for an “unroll developable surface” routine for AutoCAD.

 

 

 

It may be the routine, but it seems like there is a slight skew to the top cut on that piece. Whatever the reason, the unrolled geometry is not perfectly symmetrical.

BASE PIECE_Wrap.dwg

[paulmcz]

Here’s the work of an early (extremely limited) prototype for an “unroll developable surface” routine for AutoCAD.

 

 

 

It may be the routine, but it seems like there is a slight skew to the top cut on that piece. Whatever the reason, the unrolled geometry is not perfectly symmetrical.

 

Did you add the blue cylinder there? I didn't see it on the Andrew's drawing.

 

If the center lines indicate the axes of the two pipes and they are connected at one point, the assembly can be drawn in 2D view that is perpendicular to both axes. In that case my 'pipe-cut' lisp can still be used. Do you see it the same way?

[SEANT]

Yes, I did recreate that blue cylinder, as well as the topplane.

 

 

 

I suspect that the intension is for a symmetrical (planar assembly) piece.

 

 

 

This particular solid, however, seems slightly off. I’m basing that on the comparison of thegeometry returned from the _xedges command. The edges returned would explain why my flattened geometry is not symmetrical.

[paulmcz]

Well, we'll know what the situation is if Andrew posts the 2D views of the assemply.

[scj]

Perhaps it could be interesting for you to have a look at my

http://www.black-cad.homepage.t-online.de/abwallen.htm

Please notice, that the cross-sections of the tubes are elliptical.

Regards

Jochen

[andrew239]

here are the ortho views of the yellow pipe from the earlier post

ortho views.dwg

[paulmcz]

Will this piece be assembled (welded) with some other piece or pipe? If so, do you have the assembly drawing in 3 views 2D?

[paulmcz]

Something like this (attached)?

3V2D.dwg