Standard Components
Common off-the-shelf elements and fits for jigs and fixtures. Verify against your supplier's catalog and local standards before ordering.
Drill Jig Bushings
Bushings guide the drill. Press-fit bushings are fixed in the jig plate; renewable bushings can be replaced when worn; liner bushings receive renewable bushings.
| Type | Fit | Application |
|---|---|---|
| Press-fit (fixed) bushing | H7/r6 | Steel jig plates; low wear, seldom replaced |
| Renewable (slip) bushing | H7/g6 | Replaceable when worn; high-volume drilling |
| Liner bushing | H7/r6 (outer) | Pressed into the plate; inner bore H7 receives slip bushings |
Locator Pins
| Pin type | Application |
|---|---|
| Round pin (cylindrical) | Locates a hole in two directions; press or slip fit in the body |
| Diamond (relieved) pin | Second hole locator; locates one direction only, tolerates center-distance error |
| Flat / conical rest pin | Support point on primary datum plane |
| Adjustable rest pin | Leveling on uneven or cast surfaces |
T-Slot & T-Slot Nut Sizes
| T-slot width a (mm) | Bolt / stud size |
|---|---|
| 10 | M8 |
| 12 | M10 |
| 14 | M12 |
| 18 | M16 |
| 22 | M20 |
| 28 | M24 |
T-slot dimensions follow ISO 299 / GB/T 158. T-slot nuts are placed from the open end of the slot.
Metric Coarse Thread Bolts
| Thread | Pitch (mm) | Stress area (mm²) | Proof load 8.8 (kN) | Proof load 12.9 (kN) |
|---|---|---|---|---|
| M3 | 0.5 | 5.03 | 3.2 | 4.9 |
| M4 | 0.7 | 8.78 | 5.6 | 8.5 |
| M5 | 0.8 | 14.2 | 9.1 | 13.8 |
| M6 | 1.0 | 20.1 | 12.9 | 19.5 |
| M8 | 1.25 | 36.6 | 23.4 | 35.5 |
| M10 | 1.5 | 58.0 | 37.1 | 56.3 |
| M12 | 1.75 | 84.3 | 54.0 | 81.8 |
| M16 | 2.0 | 157 | 100 | 152 |
| M20 | 2.5 | 245 | 157 | 238 |
| M24 | 3.0 | 353 | 226 | 342 |
Proof load = proof stress × stress area (8.8 → 640 MPa, 12.9 → 970 MPa). Size clamp screws so working force stays well below proof load.
Reference Standards
- ISO 286 — ISO system of limits and fits
- ISO 965 — ISO metric screw threads
- ISO 2768 — general tolerances
- ISO 299 — machine tool tables and T-slots
- GB/T 1800 — limits and fits (China)
- JB/T 8045 — jig bushings for machine tool fixtures (China)
Bushing Mounting
Locate the bushing close to the work surface to keep drill deflection low and hole position accurate.
Two-Hole Locating
Round pin fixes both axes; the diamond pin accepts center-distance error between the two holes.
T-Slot (ISO 299)
The T-nut slides in from the open end of the slot and locks into the undercut.
Rest Pins
Rest pins support the primary datum plane; adjustable pins level uneven or cast surfaces.