For several years I have bought cheap high carbon blads from different origins anf also bimetal blades from different sources. What I have found is that many people use about 2 or 3 inches of the center of the blade with a back and forth motion as fast as they can. After reading about useing plenty of lard oil on the instructrions of my grandfathers Greenfield Tap and Die set, I started using bacon grease on my hacksaw blades. Even the cheap blades outlast other blades without bacon grease. I use bacon grease for drilling and tapping and also use it on my files to decrease the occurance of pins and to make it easier to clean off my files. Bacon grease seems to aid in the cutting action while automotive oil seems to a detreriment to the cutting action. Anyway, my two cents worth, you may have different results.