Workshop: Coolant-Through T-Slot & Keyseat Cutters Before Coating

T-slot and keyseat operations often run in enclosed grooves where flood coolant struggles to reach the bottom of the cut. Adding a coolant-through bore from the shank toward the form edges helps deliver pressure where chips form, improving evacuation and thermal stability — especially in alloy steels and stainless where built-up edge and packing can damage the profile.

This photograph was taken inside our Changzhou facility after grinding was complete and before any PVD or other coating was applied. At this stage the carbide substrate geometry is final: the T head, neck clearance, and cutting edges are fully defined, and the central coolant holes are drilled and deburred to match the customer’s pressure and flow specification. Coating is applied only after dimensional approval — the dark finish you see in catalogue photos comes later.

Manufacturing a form tool with an internal coolant path is more demanding than a solid profile alone: the bore must stay concentric with the outer form, leave enough web strength at the thinnest sections, and seal reliably in the holder. We verify runout, profile, and coolant integrity so the tool behaves on the machine as designed.

If your T-slot or keyseat programme needs through-tool coolant — long reach, heavy engagement, or difficult materials — send the section drawing, shank type, coolant pressure available at the machine, and production volume. We can quote custom solid carbide T-slot or keyseat end mills with or without coolant-through, with lead times that reflect engineering review, grinding, coating, and final inspection.