Lets put some numbers on this

So at this point we’re completely off script.  A truly code compliant fence is out of the question.  Which is OK in a sense because the vast majority of other fences aren’t either?  Point is I’m not handling 6 inch pipe.

So lets put some numbers on this thing so far.

The footers turned out about 33.5 inches tall by about 18 inches in diameter.  Yes, the original plan was to use 10 inch footers, but I’m attributing my lack of skill and perhaps equipment issues to just not having that much control over the hole size (that’s what she said).  I’m using a 10″ auger bit, but by the time I’m done the hole is about 18 inches in diameter.  On top of that I had to adjust the hole because I couldn’t place it with any sort of accuracy.  So in order to have the desired clearance between the rebar and outside world in the form’s required location I had to adjust the hole boundaries.

So assuming that the cow is a perfect sphere, the volume of each footer is \( 8524.7171 in^3 \) or \( 4.9333 ft^3 \).  According to the Quikrete data sheet, an 80 lb bag yields \(0.60 ft^3\).  If we assume that standard arithmetic applies, that’s 8.2221 80 lb bags.  This is well inline with the 7 – 10 bags that each hole took.  It’s always a nice little treat when reality and math align.

Each post is 75 1/8 inch 3″ NPS schedule 40 pipe.  The pipe, according to the schedule, weighs 7.576 lb/ft. So that’s 47.4308 lb of steel per post.  There’s the base plate and various other small fittings, but those don’t add up to more than a pound or so.

So each post is somewhere between 600 say 850 lb of steel and concrete.  The two gate posts are in heavier footers because I poured them last and had to embiggen the holes to get the desired placement accuracy. Speaking of accuracy, the two gate posts are within a 1/16 of an inch.  The outer poles are within a 1/8 of an inch.  I’m very happy with those results.

Overall I am pleased with how this project is progressing.  It’s slow going for sure, but this is my first time doing any real design, metal fabrication, and concrete work.  Concrete work has proven to be the toughest.  That son of a bitch is wet, heavy, and caustic.  But it’s a hell of a workout.