This is one of the best pieces of advice I was ever given. When building
a kit or ARF the instructions almost always state use 2-4 sheet metal
screws to attach the landing gear to the plywood doubler. All well and good
but I have found from experience that if you replace the sheet metal screws
with 2 nylon bolts ( like wing hold down bolts ) and you hit a bump/depression
/curb or other assorted obstacle you will not rip out the entire underside of
your plane ( i speak from experience ! ) all that will happen is the nylon
bolts will shear

A couple of tips re this technique - 1st drill out the plywood doubler to a slightly
smaller size than the bolts and then tap out the doubler to the correct bolt
size - makes them nice and snug. 2nd - always leave at least 3/4 in of bolt
protruding on the inside of the fuse as this gives you something to grip if
they do shear. 3rd - running a nut of the appropiate size up to the bold head
and slicing the excess material on the bolt to match the nut hex shape will
allow you to use a socket to attach and detach them ( much faster ) and
lastly to ensure they do shear when they hit something ( hey trust me it happens !)
it can be helpfull to take a drill bit aprox 1/3 the diameter of the nut and pre-drill
about 1/3 to 1/2 the length of the bolt - This also works great for wing hold down
bolts incidently ( a drill press is very useful for this )

This technique has saved my bacon more than once and while it may take a
little longer than screwing in 4 screws it is substantially shorter than a complete
rebuild of the underside of your plane

Hope this saves someone a rebuild - REBUILDING SUCKS !!

Christopher