Guide to Preset Drilling Sizes

The preset average or 'house' drilling is only recommended for those getting their first ball or have no access to a pro shop. These drillings are available as a drop down option on polyester balls, novelty balls and a few of the starter reactive urethanes.  As house balls hole sizes are not constant from bowl to bowl, below is an approximate guide to the hole diameter sizes and spans drilled by Bowling World 2000:
 
XS - Thumb 17 mm (21/31") , Fingers 15 mm (5/8"),  Span 50 mm (2")

S - Thumb 18 mm (23/32"), Fingers 16.5 mm (21/32"), Span 64 mm (2 1/2")

SM - Thumb 20mm (25/32""), Fingers 17mm (11/16"), Span 70mm (2 3/4")

M - Thumb 21.5 mm (27/32"), Fingers 18 mm (23/32") , Span 76 mm (3")

M/L - Thumb 23 mm  (29/32"), Fingers 19.5 mm (25/32"),  Span 80 mm, (3 1/8")

L - Thumb 24.5 mm (31/32") , Fingers 20.5 mm (13/16"), Span 83 mm (3 1/4")

XL - Thumb 25.4 mm (1"), Fingers 21.5 mm (27/32"),  Span 86 mm (3 3/8")

XXL - Thumb 26.5 mm  (1 1/32"),  Fingers 23 mm (29/32"),  Span 89 mm (3 1/2")

As the thumb is the most important of the above measurements the following size comparisons may be helpful. Please note this is a guide only and it is still the customers responsiblity to ensure the measurements you choose are right for you.

17mm (21/32") is approximately ring gauge size M.

17.5mm (11/16") is approximately ring gauge size P.
 
19mm (3/4") is approximately ring gauge size S.
 
20.5mm (13/16") is approximately ring gauge size W.

22mm (7/8") is very slightly larger than the largest ring gauge size Z+1/2.

24mm (31/32") is the inside diameter of a Gaviscon Tube.

26mm (1 1/64") is the inside diameter of most small rolls of Scotch Tape that fit in a dispenser.

There are ways of measuring your thumb size which can be viewed under Measuring Your Hand which is on the lower horizontal menu (PC) or the starter menu (Smart Phone).

Please note that balls drilled to the above measurements cannot be returned unless there is a fault with the ball.

All measurements are nominal.