422 provided along its sidewall preferably the slot 422 extends the length of the sidewall of the bushing 420 such that the bushing 420 has a non closed annular shape the bushing 420 is preferably a metal such as bronze the bushing 420 is inserted into the shaft opening 404 the slot 422 of the bushing 420 need not be aligned with the slot 406 of the tilter shaft holder 402 the tilter shaft 430 may then be inserted into shaft opening 404 the arm mount 440 may be inserted into the channel 144 of the forearm extension 140 fig2 as seen in fig1 the arm mount 440 may extend perpendicularly through the tilter shaft 430 preferably both the arm mount 440 and the tilter shaft 430 are a metal such as aluminum the arm mount 440 may be welded to the tilter shaft 430 when the arm mount 440 is securely attached to the forearm extension 140 the adapter plate 302 may be adjusted rotating about the axis c until the electronic device is appropriately positioned then the locking mechanism 470 is engaged by e g inserting the set screw into the bore and tightening to close the slot 406 and the slot 422 to restrict rotation about the axis c a lock washer 472 and or.