Often Razor Blades are described as 9 razor blades or #9 razor blades. This means that the razors have a thickness of .009” which is considered standard duty strength for a single edge razor blade. 12 razor blades or #12 razor blades refer to blades with a thickness of .012”. These #12 razor blades are considered heavy-duty razors and are suitable to tasks where the blade is under more pressure. Both razor blades fit all standard razor blade tools and can be interchanged depending on your task.
Some tasks require the single edge blade to be bent slightly. 9 Razor blades have more give whereas 12 razor blades are harder to bend. Another feature that affects the pliability of a razor is the construction; number 9 blades with stainless steel back are much harder to bend than those with an aluminum back. The backing of a single edge razor blade is the folded over portion at the top of the blade.
#9 Razor blades are more common and thus we carry a larger variety of #9 options including carbon steel, stainless steel, blue carbon steel, un-backed, and extra sharp varieties. We offer #12 blades from the American Line brand as well as unbranded versions. All of our #12 blades are constructed from carbon steel, however, we accept custom orders for #12 blades in stainless steel or with a double honed edge.
If you are trying to match the thickness or construction of a blade you already use, we can always send samples of our #9 and #12 razor blades so you can compare and test the product for your specific application.