i have been having a discussion with someone about double bolting the droop...it occured to me to do some simple math...here is what i come up with:
7 inches ~=~ diameter at the droop/bowl interface
38 square inches ~=~ area of the droop/bowl interface
~300 pounds per square inch ~=~ bowl pressure (nice healthy big block like an unnamed sombody intend to run (an A impeller at 5900rpm)
~11400 pounds trying to separate the droop from the bowl
8 bolts puts this at ~1400 pounds on each bolt
each bolt is a 5/16" bolt...about 1/4 inch diameter of actual metal that the force is bearing upon...or ~ .05 (1/20) of a square inch.
~28000 psi is the force on each fastner by my dogfish90 calculation.
this is quite near ~70% the yield strength of some stainless steels that are commonly (the unnamed sombody) and many others use as studs in this application, but only 1/5 the ultimate strength.
Because i dont know I have not included the stress that the nut that holds the droop onto the bowl has on the stud...it has already preloaded the fastner to some extent, and in most cases the fastner is at an angle increasing the local stress further.
Because i cant quantify it I have not included the shock forces that unloading and reloading the pump has on these fasteners...it is going to happen...the waters and the way we run...it is going to happen.
i may be a little off on the bowl pressure, i guessed. I dont suppose wrong enough to change the story.
i have not included the fact that stainless (especially near aluminum and salt water) will do some unexpected corrosion stuff on you.
am i wrong that the bowl needs to be double bolted?
where have i gone wrong with the math?
does the reaction of the water leaving the nozzle offset these calculations and if it does, does that make the unloading/loading even that more hazardous?
i dont think double bolting can hurt but at what point is double bolting necessary?
Can i use this as a cheet
EDIT: i fix the 5/8 5/16 thing