The most popular material for the shaft of the cue is straight-grained ash. The grain should not be too wide: about ten grain lines to the inch (four to the centimetre) looks good and is sufficient to promote the required shaft strength. Maple is also a perfectly good material, but because of its density it does tend to push the cue ball off the intended line when 'side' is applied. In my experience a cue tip size of 0.38in (9.75 mm) allows the ball to hold its intended line more accurately. (The tip size required also depends on the actual stress strength of the particular piece of timber used in the cue.)
Then if order maple 's cue, the tip must use 9.75mm??????