Tube Coping Calculator
They explain quite a bit on the tube Cope Calculator page. However, I experimented on the 2 3/8" oilfield pipe which is actually 2" Sch 40 pipe.
For the O.D. I found that 2.412" and wall thickness of .16" worked the best. Probably due to rust/dirt.
For the smaller oilfield pipe which is 1 1/2" Sch 40 pipe I used 1.904" as O.D. and .147" as wall thickness.
I haven't tried it on the 2 7/8" oilfield pipe yet.
When I am done calculating I click the PDF link under the drawing but make sure you print "actual size" or it won't fit your pipe.
Here is a chart of pipe with OD, wall thickness, weight per foot, etc:
Other links you might use:
Engineering Tool Box
Lehigh Valley Abrasives
King Metals Weldable Elbows, End Caps, Tees
Drillco Nitro Drill Bits
Nitro Drill Bits
Grizzly Band Saws
Ellis 1600 Band Saw (Linweld $2300)
One Torch 7-5202 also need 7-3465 adapter
Thermal Dynamics One Torch Information
Gehl 5635 Parts Manual