Bits / Workshop reference
Straight bits & flat-end cutters
Plan flat-bottom grooves and pockets without confusing cutting diameter, shank size or plunge capability.
In everyday language
Make a place for a shelf to sit
A flat-end cutter can leave a flat-bottom channel. Its round shape still leaves curved inside corners.
Draw a channel for an actual measured shelf thickness, then plan a matching sample before the final piece.
What to notice: Check the fit, floor and corners separately. The bit's cutting width is not always its holding diameter.
Can a round cutter make a perfectly square inside corner?
No. Allow a suitable corner shape, add a planned relief, or finish that feature with another process.
No need to know the vocabulary first
A few words, explained
- Collet
- The gripping sleeve that holds the shank of a cutting bit.
- Shank
- The part of a cutting bit held by the machine, distinct from its cutting diameter.
- CAM
- Computer-aided manufacturing: software used to prepare the machine's cutting movements.
- Plunge
- A movement that takes a cutting tool down into material. Not every tool permits this.
- CNC
- Computer numerical control: a computer directs a cutting machine.
- Stock
- The wood or other material you start with.
How it works
A square-ended cutting envelope leaves a nominally flat floor and vertical walls. Inside corners retain a radius related to the cutter radius.
When to consider it
Use an appropriately rated straight or flat-end tool for dados, grooves and pockets in its listed materials.
Where it does not apply
A flat-looking end is not proof of a center-cutting or plunge-rated tool. A router bit is not automatically a drill.
Before the first cut
- Enter cutting diameter—not shank diameter—in CAM and the feed calculator.
- Use the tool maker's supported entry method and depth guidance.
- Test joint fit with measured material thickness; nominal plywood thickness and nominal cutter diameter may not produce the desired fit.
Review collet engagement & stickout · Review material setup & zero
If the result looks wrong
Stop the machine and make it safe to inspect before checking the tool or workpiece.
Joint is too tight
Measure the actual groove and stock; check deflection and tool diameter before adjusting the drawing.
Rounded inside corners interfere
Design a relief or use another process; a round cutter cannot create a perfectly square internal corner.
Use the matching calculator
Calculator outputs describe geometry, time or cost—not permission to operate at those values.
Make the setup repeatable
In Machine & Bit Settings, keep these details in the standard fields, additional fields and setup notes. Record a test date only after testing that exact setup.
- Cutting diameter and shank diameter separately
- Entry method
- Measured groove and stock thickness
No cutting settings are automatically supplied or saved by this guide.
References & exact specifications
These public references explain the tool families or software features. Locate your exact part number and machine manual before setup; product families are not interchangeable.
Guidance reviewed September 2026. Diagrams are original simplified explanations, not manufacturer drawings.