A portable circular saw adapted to receive a flush mounted circular saw blade, the blade including a central, mounting portion having opposed first and second surfaces, and a cutting portion with opposed first and second planar surfaces extending from the central mounting portion to a cutting edge disposed along the blade perimeter, the rotation of the cutting edge defining a blade arc, the saw comprising: a. opposed forward and aft ends (12, 14) defining a longitudinal direction; b. a motor frame portion having opposed forward and aft ends (30, 32), the motor frame portion including: i. a motor connectable to a power source, the motor mounted to the motor frame portion and operably coupled to a drive shaft, the drive shaft projecting from a first lateral side of the motor frame portion, the drive shaft defining a first transverse axis; and, ii. a blade shield axle extending transversely from the motor frame portion first lateral side coaxial with the drive shaft; c. a handle portion coupled to the motor frame portion aft end, the handle portion including a hand grip and a motor actuator to selectively actuate the motor; d. a blade deck rigidly coupled to the motor frame portion first lateral side, the blade deck including a planar bearing surface: e. an arbor coupled to the drive shaft, the arbor including a first mounting face adapted to mate to a blade central mounting portion, the distance from the blade mounting face surface to the blade deck planar bearing surface defining a blade offset depth; f. a lower blade shield movable between a deployed position and a retracted position, the lower blade shield having an arcuate laterally projected sidewall circumscribing a portion of the blade arc from a sidewall first end to a sidewall second end, the arcuate sidewall including a facing edge coplanar with the blade deck bearing surface, the lower blade shield rotatably coupled to the blade shield axle; g. a base deck extending longitudinally from a forward edge to an opposed aft edge and transversely from a first lateral edge proximal the motor frame portion first lateral side to a second lateral edge, the base deck edges (68, 70) defining a planar bearing surface, the base deck pivotally coupled to the motor frame portion about a second transverse axis and lockable at a plurality of user selectable pitch angles about the second transverse axis to adjust the blade cutting depth, the base deck further pivotally coupled to the motor frame about a first longitudinal axis and lockable at a plurality of user selected bevel angles about the first longitudinal axis. a. opposed forward and aft ends (12, 14) defining a longitudinal direction; b. a motor frame portion having opposed forward and aft ends (30, 32), the motor frame portion including: i. a motor connectable to a power source, the motor mounted to the motor frame portion and operably coupled to a drive shaft, the drive shaft projecting from a first lateral side of the motor frame portion, the drive shaft defining a first transverse axis; and, ii. a blade shield axle extending transversely from the motor frame portion first lateral side coaxial with the drive shaft; i. a motor connectable to a power source, the motor mounted to the motor frame portion and operably coupled to a drive shaft, the drive shaft projecting from a first lateral side of the motor frame portion, the drive shaft defining a first transverse axis; and, ii. a blade shield axle extending transversely from the motor frame portion first lateral side coaxial with the drive shaft; c. a handle portion coupled to the motor frame portion aft end, the handle portion including a hand grip and a motor actuator to selectively actuate the motor; d. a blade deck rigidly coupled to the motor frame portion first lateral side, the blade deck including a planar bearing surface: e. an arbor coupled to the drive shaft, the arbor including a first mounting face adapted to mate to a blade central mounting portion, the distance from the blade mounting face surface to the blade deck planar bearing surface defining a blade offset depth; f. a lower blade shield movable between a deployed position and a retracted position, the lower blade shield having an arcuate laterally projected sidewall circumscribing a portion of the blade arc from a sidewall first end to a sidewall second end, the arcuate sidewall including a facing edge coplanar with the blade deck bearing surface, the lower blade shield rotatably coupled to the blade shield axle; g. a base deck extending longitudinally from a forward edge to an opposed aft edge and transversely from a first lateral edge proximal the motor frame portion first lateral side to a second lateral edge, the base deck edges (68, 70) defining a planar bearing surface, the base deck pivotally coupled to the motor frame portion about a second transverse axis and lockable at a plurality of user selectable pitch angles about the second transverse axis to adjust the blade cutting depth, the base deck further pivotally coupled to the motor frame about a first longitudinal axis and lockable at a plurality of user selected bevel angles about the first longitudinal axis.