Carbide Versus HSS Tooling

Basic info on the differences between carbide and high speed steel cutterhead knives. August 15, 2011

Carbide vs. HSS. What is the difference between the two? Is one preferred over the other on certain machines (shaper, router, planer, etc.)?

Forum Responses
(Cabinetmaking Forum)
From contributor S:
Carbide lasts longer between sharpenings but does not take as good of an edge, is brittle, and requires diamond sharpening equipment. HSS (and other steel alloys) take a sharper edge and make a nicer cut, but dull faster. They are more easily sharpened and can be done by hand in some cases. Which you choose depends on a lot of factors. Insert tooling? Long production runs? Short runs? Small single knife moulder or a 6 head moulder? For most shops a combination of tooling is the solution.

From contributor H:
Contributor S is correct, HSS can be ground to a finer edge, but it will also not hold up as long in any man-made materials. Glue lines will eat it up also. Carbide seems to be the choice now. HSS will take more vibration and will not break as easy on small patterns but same thing, it will not hold up long. HSS has to be made in very large qty's and due to the economy, most have elected to focus on carbide.

From contributor L:
Like with almost everything there is a considerable range within each material. Steel is easy to work with and can run from very soft to quite hard. If you are old school you can hand grind it for shaper heads. Works well on solid wood that does not have mineral streaks. Brazed carbide comes on lots of quality levels as does insert carbide. If you can justify the cost I'd go for insert tooling over brazed. The inserts will run longer than brazed and you can get the inserts in a variety of grades to suite the material. Man made board and solid wood with glue lines do much better with carbide than steel.

Everything has tradeoffs! We compromise on the molder by running a softer steel that doesn't chip as easily but gives shorter runs than the hard steel. Most of our runs are short. We use the double back carbide system for straight knives and get excellent mileage. They are fragile and expensive but hold up very well and give an excellent cut quality. We can also grind them in house. The tooling guys can make recommendations based on your uses.

From contributor U:
For straight knives like on a jointer, carbide is great. And you can run materials which would just wipe out HSS.I can join the edges of laminated plastic. I only have to sharpen mine about every two years. I can do it in house with a simple diamond wheel.