Knew Concepts fret saws are ideal for dovetail and coping work. We carry both the 3in and 5in versions of these saws. The Mark 4 saws are designed to pull between 50-60 pounds on their blades, the Mark 3 approximately 40 lbs. All the models we carry can be swiveled, which we think is an amazing improvement over standard fret saws. Choosing between the two models comes down to lightest weight, go with the Mark 3. For the ultimate in tension, go with the Mark 4.