NEWS & GUIDES
Choosing a T-slot or dovetail cutter
Choose between a T-slot cutter and a dovetail cutter from the cross-section of the finished feature. Both can machine material beneath an overhanging edge, but they produce different profiles. A photograph of the cutter is less useful than a dimensioned section through the slot you need to make.
Match the feature, not just the cutter diameter
| Requirement | T-slot cutter | Dovetail cutter |
|---|---|---|
| Finished profile | Undercut with a T-shaped section | Angled undercut defined by the drawing |
| Key cutting dimensions | Head diameter and cutting width | Diameter, cutting height and the defined angle |
| Access checks | Slot opening, neck clearance and entry route | Opening, neck clearance and access to the angled faces |
| Connection checks | Shank or taper, retention and required reach | Shank or taper, retention and required reach |
Our T-slot cutter catalog and dovetail cutter catalog list different dimensional groups. Check the complete row rather than combining a diameter from one entry with an angle, width or taper from another.
Show how the tool enters the feature
Mark whether the tool can enter from an open end, through a permitted entry hole, or only through the slot opening. Include the depth below the top surface and any clamps that restrict access. A cutting head may fit inside the finished cavity but still have no route into it.
The neck is also important: a large cutting head does not mean the narrow section behind it can support any chosen cut. Harvey Tool’s dovetail application guidance explains why neck geometry, entry access and chip removal need attention. Its examples concern particular tooling; use the actual supplied cutter’s instructions for cutting conditions.
Clarify the angle convention
A note such as “60 degrees” is incomplete if the drawing does not show which faces or axes define it. Mark the angle directly on the section view and specify the intended finished dimensions. Do not assume a catalog angle, a flank angle and an included angle are interchangeable descriptions.
Plan the preparation and machining information
Show the slot or pocket that will exist before the undercut operation, including its width and depth. Do not assume the selected undercut cutter can plunge into solid stock. Identify the material and condition, machine spindle, available coolant or chip-clearing method, workholding and required finish.
Feeds and speeds cannot be transferred solely because two tools share a diameter. Cutter construction, engagement, neck geometry and material all matter. Kennametal’s KTMS information, for example, describes a particular indexable T-slot system, not universal settings for our catalog cutters.
What to include in your inquiry
- Part section and drawing revision, with all units visible.
- Slot opening, undercut width or profile, depth and any corner requirements.
- Permitted entry route and available neck and holder clearance.
- Required shank or Morse taper and retention arrangement.
- Material, quantity and requested inspection criteria.
Browse milling cutters and reamers, or send the feature drawing if no listed row clearly fits. References checked 5 September 2026.