The circular blade is carbide tipped, 24 tooth. SInce it is the upstroke of the teeth exiting the cut, the blade is leaving a partially splintered edge in the 12 year old laminate hardwood, and as I said, 3M blue masking tape didn't stop that. Perhaps a fine tooth conventional blade would be better.
The SoniCrafter might work okay for a short distance, but for 13' I just haven't the patience. The wood cutting blade tends to flex if you put any pressure on it sending you off the line which is always covered in dust. I am cutting into the line horizontally, not vertically, to save the teeth but you get a lot of chatter on the concrete.
And yes, the depth on the 4"er was set to clear the concrete. Kinda sparks a bunch if you don't.