Mortise Bit Buying Guide : eReplacementParts- best mortise chisel bits for metal ,Mortise bit length and bit diameter can also vary. Mortise Bit Care and Use Here is a list of things that help mortise bits last long and perform their best: Keep chisels sharp. Lubricate the bit. Square the bit to the fence. Adjust the center bit properly. Use the right drilling technique.Top 9 Mortising Attachment for Drill Press – Multitools ...WEN - 4-1/4 inch spindle travel creates mortises up to 3 inches in depth. Features a spacious 13-1/2 by 6 inch table and a 10 by 8 inch cast iron base. Includes three chisel bits 1/4, a chuck extension adapter, a protective chip guard, 3/4-inch chisel bushing, depth stop, and 1/2 inch, 3/8, spring-tensioned fence, an adjustable handle, and a two-year warranty.