Hello,
I see that you are a plumber by trade. I have a question for you. In the last 3 months, I have had two drain pipes crack right at the edge of where the pipe entered into an 90 deg elbow. The pipe is the 1 1/2 " black pipe. My house was built in 1972.
Do you know of any issues with the pipes or perhaps the adhesive used during that time period?
Thanks,
Richard
I might take the drilling jig and drill a bunch more holes in it but only drill the top side.