After importing an object from blender and setting every mesh to cast and receive shadows, I noticed that the rendered shadows are incorrect. Even after merging the meshes thinking it would solve the issue, the problem persisted. It seems like using side: THREE.DoubleSide resolves the problem, but it darkens the materials.
LIGHT SETTINGS
light = new THREE.DirectionalLight( 0x666666, 1 );
light.position.set( 2*400, 2*300.75, 2*400);
light.position.multiplyScalar( 1.3 );
light.castShadow=true;
light.shadowMapWidth = 2048;
light.shadowMapHeight =2048;
var d = 1300;
light.shadowCameraLeft = -d;
light.shadowCameraRight = d;
light.shadowCameraTop = d;
light.shadowCameraBottom = -d;
light.shadowCameraFar = 10000;
light.shadowBias = 0.0001;
light.shadowDarkness = 0.5;
MATERIAL SETTINGS
var childTilesTexture = THREE.ImageUtils.loadTexture('texture/wood_t.jpg?v1');
childTilesTexture.wrapS = childTilesTexture.wrapT = THREE.RepeatWrapping;
child.material = new THREE.MeshPhongMaterial( { map:childTilesTexture, shininess:5, metal: false} );
SCREENSHOTS
https://i.stack.imgur.com/bsKnU.jpg
ANOTHER SCREENSHOT
Upon closer inspection, it is evident that the handles are casting a shadow through the object box.