Abstract:Using the ellips-parabolid log model with the four practical measurable parameters, it is measured that the exact volume of all the uncut-boards and clabs cut by the multi-bit ripping edger. The loss of the saw Kerf and recovery have be accurately calculated. By the theroies, a quite simple NC detecting system of the multi-bit ripping eddger will be desinged which made the numerical control for the maching of short cycle wood for timber industry realizable.