Looks like you can carry a switchblade with a blade up to 1 1/2 inches.
C. 269, Section 10... (b) Whoever, except as provided by
law, carries on his person, or carries on his person or
under his control in a vehicle, any stiletto, dagger, or a
device which enables a knife with a locking blade to be
drawn at a locked position, any ballistic knife..., dirk
knife, any knife having a double-edged blade, or a switch
knife, or any knife having an automatic spring release
device by which the blade is released from the handle,
having a blade of over one and one-half inches... shall be
punished by imprisonment for not less than two and one-
half years nor more than five years in the state prison...
except that, if the court finds that the defendant has not
been previously convicted of a felony, he may be punished
by a fine of not more than fifty dollars or by
imprisonment for not more than two and one-half years in a
jail or house of correction.