How do I draw a bent steel tube?

Hi. I already know the basics of 2D and a little of 3D. I know how to draw a cylinder, but what if the cylinder is bent like an arc? Like a bent steel tube.

Note: Steel tube is different from steel bar. Steel bar is solid; if you draw it in 3D you should use the 3DFace command to give it a solid look, correct?

What I want to draw is TUBE (like a cylinder) that is bent to an arc, with a diameter of 50 drawing units. How do I do it?

Please don't suggest REVOLVE. I think when you revolve an object it is automatically created with 3D Faces, thus making it solid. A tube is not 'solid' but hollow. Also, if you could teach me how to give the tube a thickness please do so. I'm referring the the thickness of the 'wall', not the diameter of the circle. For example, the tube is 1" in diameter with a thickness of 1.00mm.

If the details I provided isn't clear please let me know. Thanks!!!

One way would be to EXTRUDE two circles along a "path". These represent the I.D. and O.D. of the tube. Then use the SUBTRACT command to subtract the inner circle from the outer circle. The "path" can be straight or it can have a bend in it. I usually use a polyline for the path. I also place the center of the circles at the endpoint of this path.

i do this exactly how remark said. Because you are dealing with solids the only way for you to get a tube would be to subtract a second tube from it. you could also use the shell command but this would add extra steps for you as the ends would be closed and would need slicing or subtracting.

One thing to note about your path is it has to be a polyline, cannot be a spline for extrude path(at least i dont think so). If you need to include arcs these can only be drawn in the xy plane. Same thing for circles so you will have to manipulate your UCS to allow your path and your circle to be tangent(if you wish to include bends. another option is draw your path with all straight lines, fillet at the edges and PEDIT to join them all together.

I drew this awhile back to show someone else how to do tubingruns.

http://i268.photobucket.com/albums/jj39/shift1313/cad/extrusionhelp5.jpg

http://i268.photobucket.com/albums/jj39/shift1313/cad/extrusionhelp6.jpg

Draw two circles, convert them to regions and subtract the inner from the outer one. Create the centerline as a polyline starting from the circles center and perpendicular to the circles plane. Extrude the region using the centerline as path.

Welcome to the forum!

Here is a good example tutorial as someone else pointed out to me not too long ago

http://www.caddigest.com/subjects/AutoCAD/tutorials/select/082003_parsai_extrude.htm

draw 1"Ø, offset it to your desired thickness, press together ctrl+alt, click the space in between the thickness, if the 2 objects form into a broken line. release ctrl and alt, then pull. (cad '08 tips n tricks)

There you go. More ways to skin the proverbial cat than you thought possible. Try one or try them all.

Thanks guys!

with regards to the ReMark's suggestion, I should create a region first before executing the SUBTRACT command, correct? Thanks!

The technique would work both ways. My suggestions requires the user to extrude first then subtract one solid from the other. With regions you subtract first then extrude.

with regards to the ReMark's suggestion, I should create a region first before executing the SUBTRACT command, correct? Thanks!

yes, the subtract will not work without the region command if you just have the two circles on the screen. If you use region you need to draw your circles, region, then subtract then extrude. The other methods are draw two circles, extrude, then subtract(two solids).