Hand rails getting bolts threaded into the teak and then them will be plugged

Having marked off the position of the bolt hole position drilled a plug hole and then drilled out the bolt hole 0.5 mm under size so that the bolt could be threaded into the hole and would lock in position 

Although there are only four hand rails it is a good way of setting the bolts this way round, some screw the hand rails up from underneath, however, this method make the best of holding power.