Insert carbide is the economical way to go. Each knife has two edges; saves down time. We have three different grades of carbide for various applications, such as: hard/softwood, MDF, solid surface, chipboard and plywood.#Rc-1230, diameter (D): 3/4, cutting height (B): 30mm, Shank (D): 1/2, overall length (L): 3-D/4, replacement collar: 47739, replacement bearing: 47721, replacement knives: rck-30, flutes: 2, RC-1230 insert solid carbide flush trim template 3/4 dia x 30mm x 1/2 inch shank with upper Bb