Step Drilling Hardened Steel with Imperial Cobalt Drill Bits | CUT-IT Paste Demo

Imperial Cobalt Drill Bit Demo (Pillar Drill)

In this workshop demo, Frank Cox (SmokerBuilder) shows the correct way to drill hardened steel using imperial TTP HARD cobalt drill bits with CUT-IT metal cutting paste. Starting with a 1/8″ pilot hole, he steps up through 1/4″ and finally 1/2″, applying CUT-IT at each stage. With a pillar drill and controlled speed, the cobalt bits cut smoothly without overheating or losing edge — a textbook example of step drilling done right.

Key Highlights from the Video

• Step drilling sequence: 1/8″ → 1/4″ → 1/2″ cobalt drill bits

• CUT-IT paste applied at each step for cooling & lubrication

• Pillar drill with controlled RPM for clean, accurate cutting

• Long, continuous swarf shows efficient cutting action

• Smooth results on hardened steel without tip burn or chatter

Hardened steels are designed to resist wear and heat — great for performance parts, difficult for drilling. Standard HSS bits tend to squeal, overheat, and dull rapidly. This demo shows how M35 (5% cobalt) imperial drill bits paired with CUT-IT metal cutting paste maintain their cutting edge and deliver a clean hole in tough steel.

The method is just as important as the tool. Step drilling spreads the work over multiple passes: start with a 1/8″ pilot, then open the hole with 1/4″, and finish at 1/2″. At each step, apply fresh CUT-IT paste to reduce friction, clear swarf, and control temperature. With a pillar drill you can keep a steady feed rate and ideal RPM; the result is long, continuous swarf and a smooth finish, not heat discoloration or work-hardening.

To replicate these results:

• Use slow–moderate RPM to manage heat (increase only when cutting is stable).

• Maintain steady pressure — let the bit cut, don’t rub.

• Reapply CUT-IT at each step; paste clings better than thin oils.

• Peck occasionally to clear swarf and keep the flutes cutting cleanly.

With the right cobalt bits, proper lubrication, and a disciplined step-drilling sequence, hardened steel becomes predictable and repeatable — extending tool life and improving accuracy.