I have to replace a 4" cast iron pipe with its ABS counterpart, the cast iron soil pipe was elbowed by 3 sections with total 13 degrees turn( 3-5 degrees left turn per section, in order to keep the pipe running into the concret wall). The ABS elblows are only available at 22.5, 45, 60, and 90 degrees, how can I make a 13 degree turn? Can I just connect 3 sections of stright ABS pipe with an angle of 3-5 degree per section, and glue them with ABS cement? just like the guy did it with the iron cast pipe?
Thanks.

You should be able to get 13° of deflection out of two pieces of pipe and one flexible coupling. HD sells the Fernco brand of flexible couplings, you'll want a model 1056-44. It's a cobbled setup but then again, thats what the other guy did.

Thanks vid, I will look for it around the plumbing stores in town, Thanks once again for your information.

I found I could make a 13 degrees elbow with two pieces 4" pipe and a coupling, the pipes can be plugged into the coupling in about 1/2" inch, does it work if I apply thick ABS cement around the joint? does anyone out there try this method? your advice would be highly appreciated.

Isn't the way to make aninfinite number of angles to use three 22.5 degree connectors ... dry fit the bottom one and then twist the others until they line up correctly up top.

yes, turning only 2 pieces 22.5 degrees connector can make the angle that I need, but the problem is it turns the pipe direction either up or down, making the necessary slope (1/4" per foot) impossible.

I understand.
And what if you shorten the bottom pipe slightly (I may be having trouble visualizing your piping - maybe the exit pipe is horizontal, yes?)

Yes, I have to cut out 3-4 feet of the cast iron pipe which is 13 degrees elbowed and horizontally buried under the ground in 4"-5" deep.