Tutorial Intermediate ⏱ 12 minutes

T-Slot Profile

Create a T-slot cross-section profile — the standard geometry for machine table T-slots used with T-bolts and fixtures.

What You Will Build

A standard T-slot profile: 18mm wide slot, 12mm wide neck, 10mm deep slot, 5mm deep neck. With chamfered entry edges.

Operators Used

Line/Parlel,XAxis,D Line/Parlel,YAxis,D Point/Intof,L,L Chamfer/Between,L,L

Define the T-Slot Dimensions

Plan the T-slot geometry. This example uses a standard M12 T-slot.

T-slot dimensions (M12 standard):
  Slot width (bottom):  18mm  → half-width 9mm
  Neck width (top):     12mm  → half-width 6mm
  Slot depth:           10mm  → Y from 0 to -10
  Neck depth:           5mm   → Y from 0 to -5
  Chamfer at entry:     1mm × 1mm

Profile is symmetric about X=0

Create the Horizontal Reference Lines

Create horizontal lines at each level of the T-slot.

Line/Parlel, XAxis, D=0    → L0: surface level (Y=0)
Line/Parlel, XAxis, D=-5   → L1: bottom of neck (Y=-5)
Line/Parlel, XAxis, D=-10  → L2: bottom of slot (Y=-10)

Create the Vertical Reference Lines

Create vertical lines for the slot and neck walls.

Line/Parlel, YAxis, D=-9   → L3: left slot wall (X=-9)
Line/Parlel, YAxis, D=+9   → L4: right slot wall (X=+9)
Line/Parlel, YAxis, D=-6   → L5: left neck wall (X=-6)
Line/Parlel, YAxis, D=+6   → L6: right neck wall (X=+6)

Find All Corner Intersections

Create points at all T-slot corners.

Point/Intof, L0, L5  → P0 = (-6, 0)   [left neck top]
Point/Intof, L0, L6  → P1 = (6, 0)    [right neck top]
Point/Intof, L1, L3  → P2 = (-9, -5)  [left slot shoulder]
Point/Intof, L1, L4  → P3 = (9, -5)   [right slot shoulder]
Point/Intof, L1, L5  → P4 = (-6, -5)  [left neck bottom]
Point/Intof, L1, L6  → P5 = (6, -5)   [right neck bottom]
Point/Intof, L2, L3  → P6 = (-9, -10) [left slot bottom]
Point/Intof, L2, L4  → P7 = (9, -10)  [right slot bottom]

Create the T-Slot Profile Lines

Create the actual T-slot profile from the intersection points.

Line/P0, P4   → L7: left neck wall  (-6,0) to (-6,-5)
Line/P4, P2   → L8: left shoulder   (-6,-5) to (-9,-5)
Line/P2, P6   → L9: left slot wall  (-9,-5) to (-9,-10)
Line/P6, P7   → L10: slot bottom    (-9,-10) to (9,-10)
Line/P7, P3   → L11: right slot wall (9,-10) to (9,-5)
Line/P3, P5   → L12: right shoulder  (9,-5) to (6,-5)
Line/P5, P1   → L13: right neck wall (6,-5) to (6,0)

Add Entry Chamfers

Add 1mm chamfers at the slot entry edges for easier T-bolt insertion.

Chamfer/Between, L0_left, L7, D1=1, D2=1  → L14: left entry chamfer
Chamfer/Between, L13, L0_right, D1=1, D2=1 → L15: right entry chamfer

Final T-slot profile:
  Surface → chamfer → neck → shoulder → slot → bottom
  Symmetric about X=0
  Total depth: 10mm
  Slot width: 18mm
  Neck width: 12mm

The chamfers guide the T-bolt head into the slot. Standard chamfer is 1mm × 45°.

Tips & Best Practices

T-slot dimensions are standardised — use the correct standard for your machine table.
The neck width must be slightly larger than the T-bolt shank diameter.
The slot width must accommodate the T-bolt head with clearance.
Chamfers at the entry edges are essential for easy T-bolt insertion.
This profile is typically machined with a T-slot cutter in two passes: neck then slot.