Here's what I do. Get a swivel stud with machine screw threads instead of wood screw threads and a nut and lockwaxher to fit. These cost about $1.50. Drill about a 1/16" hole through the forearm. Then take a 1/4" (I think, same diameter as stud base) Forstner Bit (flat bottomed drill bit) and use the small hole for a guide and drill just deep enough for the stud to sit flat on the wood. Then take a 3/8 Forstner Bit (I think again, just big enough for nut and use the small hole for a guide to drill a hole inside the forearm deep enough for the nut to go into. Now drill the 1/16" hole with a bigger bit to put the threaded part of the stud through. Put the stud in, tigthen lockwasher and nut with a little locktite if you desire. Sometimes the stud must be cut to length.
All my Contenders and Encore are like this and I have never had one come loose.