Typical Fixtures by Machine Tool
Fixture design is driven by the machine and the operation. This page summarises the locating, clamping and mounting strategy for each major machine type.
1Lathe Fixtures
Fixtures bolt to the chuck, faceplate or spindle flange. Parts not holdable in a standard chuck are located on a register bore or face and clamped with balanced swing clamps.
- Locate on machined bore + face for true running; use a tapered pilot.
- Balance the fixture against centrifugal force and vibration at speed.
- Clamp force must resist cutting torque through friction on the drive face.
2Milling & Planing Fixtures
Must resist heavy, interrupted cutting forces. A rigid base keyed to the machine table; strong clamps and supports against the feed direction.
- Key the fixture base to the table T-slots for alignment.
- Support the part near the cut; direct clamp force toward the table.
- Clear chips with open sides and slots; use positive stops against feed.
3Drilling Fixtures
Jigs guide the drill with hardened bushings. Template (leaf), box, index and trunnion jigs cover most hole-pattern work.
- Bushings close to the surface give accurate hole position.
- Locate from machined edges or reamed holes for repeatable position.
- Open the jig for chip and coolant removal and quick loading.
4Boring Fixtures
Precision work; the boring bar is guided in the fixture or in a floating head. The fixture must be extremely rigid to hold bore position and roundness.
- Guide bushings or boring-head alignment keep the bar on the bore axis.
- Locate the workpiece on the datum features that define the bore position.
- Use hardened, ground locating and guiding surfaces; keep coolant clean.
5Broaching Fixtures
The fixture resists the full broaching pull force. Parts are located on datum faces and pressed against a rigid stop in the pull direction.
- Support directly in line with the broach pull to avoid deflection.
- Simple, fast clamping — the pull does most of the holding.
- Positive stop absorbs the cutting force; clamp only holds the part in place.
6Gear Cutting Fixtures
Hobbing, shaping and gear grinding need accurate centering of the gear on its bore with a face datum, and balanced clamping to avoid distortion of the teeth.
- Locate on the gear bore with an arbor or expanding mandrel; face datum for height.
- Clamp with low, even force to avoid distorting the gear body and teeth.
- Indexing accuracy matters for indexable (shaping) work.
7Grinding Fixtures
Highest accuracy; hardened and ground locating surfaces, fine adjustment, and clean coolant flow to the wheel and part.
- Use magnetic or vacuum holding for thin plates and non-magnetic parts.
- Minimize clamping force to prevent part distortion under grinding pressure.
- Provide for wheel dressing and coolant clearing without unclamping.
8Modular Machine & Transfer Line Fixtures
On modular machines and automatic transfer lines, fixtures travel with the pallet and must index, locate and clamp automatically at each station.
- Pallet-based locating: cone + flat + pin system for automatic transfer.
- Power clamping with sequence interlocks; clamp confirmed before cutting.
- Chip and coolant management over the whole line; self-cleaning locating seats.
- Hardened wear pads sized for long unattended service.
Universal Fixtures & Selection
Universal workholders — three-jaw chucks, collets, vises, magnetic/vacuum plates — are economical for general work. Choose a dedicated fixture when accuracy, batch size or part shape demands it. The selection table below summarises the machine-specific approach.
| Machine | Mounting | Locating | Clamping |
|---|---|---|---|
| Lathe | Chuck / faceplate / spindle flange | Bore + face, tapered pilot | Balanced swing clamps |
| Milling / planing | T-slot table, keys | 3-2-1 on machined pads | Strap / toggle / power clamps |
| Drilling | Table or rotary table | Edges / reamed holes | Strap clamps, jig |
| Boring | Table, floor plate | Datum features for bore | Strong rigid clamps |
| Broaching | Machine base | Datum face + stop | Light clamp; pull holds part |
| Gear cutting | Arbor / mandrel | Bore + face | Low even clamping |
| Grinding | Magnetic / vacuum plate | Datum surfaces | Minimal force |
| Modular machine / line | Pallet, cone-pin system | Pallet datum | Power, interlocked |