According to a customer, he used these drill bits to make knives made from Damascus steel - very hard steel. Compared to other cobalt bits, this product takes him a shorter time to do. Making holes ...

It turns out that a hot solution of alum (ammonium aluminum sulfate), which is available in the spice rack of your local supermarket, will dissolve the steel drill bit without reacting with the brass.

Moly drill bits work well with mild steel. Cobalt bits are expensive and best choice for the abuse common in farm shops, but…drill bits by definition are “consumable items.” The differences ...

Inditrust Heavy duty 13pc hss good for wood and steel drill bit set on sale, Sabre Tools 1 4 Inch Cobalt Drill Bits 5pcs Drill Bits for Metal on sale, Inditrust 5 pc heavy duty masonry wall drilling ...

HSS and cobalt drill bits can be sharpened with a standard metal file or grinding wheel. TCT drill bits need either a file encrusted with industrial diamonds or a diamond grinding wheel.