Miter Bend Drafting

My computer is acting up lately, but I will try to mail you a message via the CR4 private mail system.

What you want is a drafting topic known as developments and intersections. In your case, you need four 22.5° miters. The template for each joint consists of a sine wave whose length is the circumference of the pipe and whose amplitude is the pipe diameter times sin 22.5°. A picture is worth a thousand words, and I will try to send you the picture.

I always thought that 90/5=18.

Thanks for the new arithmetic.

4 intersections will join 5 pieces.

Like Torando, I am assuming three pieces and the two straight pipes make up the five pieces mentioned.

All five pieces will have a 11.25° bevel on each end.

You would be far better off to buy a 90° elbow, thus two welds to xray rather than six.

Very easy. Buy a book titled " Pipe Fitters Hand Book" from Industrial Press Inc., 200 Madison Avenue, New York 10016 U.S.A. Page 2-15 details through pictorial and narration. How ever if you could follow up my explanation, you might be able to do it without the Book. First of all you have to arrive on to the Radius of the Bend. Then you cut 5 equal pieces from 12 dia NPS pipe with cutting and beveling machine, straight edge that is no bevel. Length of each pipe pieces would be = Radius X 0.536 (in inches). Place all 5 pieces on sand bed so as to make 90 deg bend. This would show you that there would be 3 weld joints in one 90 deg bend. While joining these pieces to form 3 weld joint in one bend, the abutting end at outer circle of the bend is open measuring 30 degree from the center of pipe and closed at inner circle of the bend. Fix all pipe pieces with no space at inner circle. Draw a line on the center top of each pipe. Use wrap around to mark 15 degree on each pipe end. Hand-Torch (Oxy-Acetylene Torch) cut off the piece from pipe to miter 15 degree from one end and 30 degree in total from one abutting joint. First grind each abutting end straight and when there is no gap in the abutting end then bevel to required degree. Finally weld it.

I support the elbow option. It is cheaper and got less problems. More welds increase the prbability of failure and costs money as well.

Thanks to all of you.

Best regards.

Moiz Khan