After years of hand woodworking and using hand tools I have become well aware that the variety of blades to have to be sharpened is so broad as to preclude the possession of only one guide for sharpening. Thus, there is no universal guide! I proceeded to own different devices that allow me to securely support most of the blades. For plow blades I prefer to use the Stanley guide. It has the advantage of having a rear support that compensates very well the narrow width of the cutting edge, preventing the device, leaning on one side, could affect to obtain a perfectly square edge, as is appropriate for this kind of blade. The Stanley guide, however, was designed to sharpen chisels or wide blades. Metal plow blades are thin and is difficult to tight them enough. To remedy this problem I put a small wedge between the blade and the lower floor of the guide, getting a firm grip, without risk to affect the stability of the system during sharpening action. 
