On heavy good vehicles, Railway rolling stock large machinery and ships, the application of a 2lb hammer lightly tapped will without doubt satisfy most engineeres to the tightness of the relevent nut or bolt, on steel plate panels that can also be tapped you will also find any that are not tightly fastened or clamped by bolts, but I fear the application of a 2lb two faced hammer or even a tiny panel pin hammer would have a rather displeasing effect on the surface of any rotor blade or propeller.
Like wise I distrust the suggestion that this "Tap Test" is supposed to be carried out by using a two cent coin. I have many friend over here in the UK who own R44's and I have never seen any of them carry out a Tap Test on their daily check,
Is it actually in the R44 manual?
Peter R-B
Vfr