The tolerances are given in european norms ( for example ) EN 1536 for bored piles, EN 12699 for displacement piles. The tolerance depends mainly on the pile diameter in EN 1536 : 0.10 m up to 1 m diameter, 0.1 x D between 1 and 1.5 m and 0.15 m above 1.5 m diameter. these tolerances are given at working platform level ( inclination shoud not exceed 0.02 m/m according to the same norm ). If you forget about norms it is good sense to consider that tolerances should vary with the type of boring method : it will be more difficult to ensure a tight tolerance for a small diameter CFA pile than for a 1 m diameter pile with temporary casing. Piles drilled on land will be easier to position than piles drilled over water, etc.