You can use your garden hose to help lay out the borders of curved areas for gardens, flower beds, paths or small ponds. Just lay the hose along the proposed edge, check it for position, then mark out the curve by using a garden spade along the edge of the hose.
Several methods are available for dealing with screws that tend to vibrate loose on covers of equipment such as chainsaws. One good fix is to remove the offending screws and wrap 1/2-in.-wide Teflon tape around the threads and then screw them back in. The tape will hold the screws tight, yet will allow you to remove them when necessary.