The Collaborative International Dictionary of English v.0.48:

Machinate \Mach"i*nate\, v. i. [imp. & p. p. Machinated; p.
   pr. & vb. n. Machinating.] [L. machinatus, p. p. of
   machinari to devise, plot. See Machine.]
   To plan; to contrive; esp., to form a scheme with the purpose
   of doing harm; to contrive artfully; to plot. "How long will
   you machinate!" --Sandys.
   [1913 Webster]