Jigs, Fixtures & Checking Gauges

Custom jigs, fixtures and checking gauges built to your part drawings. 3-2-1 locating, repeat accuracy +/-0.02mm, CMM report and Gauge R&R included.

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kouteng@lonturn.com

Hotline:15828477070

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Product overview

Jigs, fixtures and checking gauges are dedicated tooling used to locate, clamp and quickly verify a part. In machining, assembly and welding operations a fixture keeps every workpiece in the same position and holds it securely; a checking gauge turns the dimensional and positional requirements of the drawing into a repeatable inspection routine. Locating pins, checking pins, go/no-go gauges and profile templates allow 100% inspection of batch parts instead of the sampling approach of calipers and CMMs.

The structure follows the 3-2-1 locating principle: three supports on the base plane restrain the Z direction and two rotations, two cylindrical pins restrain X/Y and rotation, and a diamond pin removes over-constraint. Clamping points sit directly above the supports so the workpiece is not distorted by clamping force. Base plates are made of 5083 / 6061 aluminium alloy or 45 carbon steel; locating pins are Cr12MoV (HRC 58-62) or SKD11, with fits controlled to H7/g6 and repeat locating accuracy of ±0.02 mm.

Typical applications include welded automotive sub-assemblies, hole position and appearance checks on injection-moulded parts, locating of die-cast parts for machining, and assembly of electronic structural components. Tooling is built to the customer’s part drawings and delivered with a CMM report and a Gauge R&R study.

1. Structure and locating specifications

Item	Typical range / notes
Base plate material	5083 / 6061 aluminium alloy (standard) or 45 steel; 15–30 mm thick, stiffening ribs optional
Locating method	One plane, two pins (3-2-1 principle); cylindrical pin plus diamond pin to avoid over-constraint
Locating pins	φ8–φ20, Cr12MoV / SKD11 hardened to HRC 58–62, fit H7/g6
Repeat locating accuracy	±0.02–0.05 mm, depending on pin pitch tolerance and base plate rigidity
Clamping	Toggle clamps, pneumatic clamping or screw clamping, selected by cycle time and level of automation
Base plate flatness	≤ 0.03–0.05 mm per 500 mm, achieved by finish machining followed by grinding

2. Checking capability

Item	Typical range / notes
Characteristics checked	Hole position, hole diameter, profile, flushness, gap, assembly interference
Checking elements	Checking pins, go/no-go gauges, profile templates, feeler gauges, visual judgement marks
Checking accuracy	±0.05 mm; ±0.03 mm for the high-precision version
Judgement method	Qualitative go/no-go plus visual check and quantitative feeler gauge; no reading required, low dependence on operator skill
Cycle time per part	10–30 s including loading, unloading and clamping
Measurement system capability	Gauge R&R ≤ 10% (analysis report issued on request)

3. Workpieces and sizes

Item	Typical range / notes
Workpieces	Welded sheet-metal assemblies, injection-moulded parts, die castings, electronic structural parts, stamped hardware
Part size	50–1200 mm; larger parts can use a spliced base plate or a segmented gauge
Base plate size	400×300 to 1500×1000 mm, 15–30 mm thick
Total weight	15–300 kg, with lifting holes or castors for handling
Surface finish	Anodised aluminium; black oxide, powder coating or hard chrome plating for steel parts
Lead time	5–20 days, depending on structural complexity and subcontract capacity

4. Configurations and options

Item	Description
Functional options	Zero-point quick-change locating, tilting mechanism, poka-yoke against missing or reversed parts, wear-resistant inserts
Materials and finish	5083 / 6061 aluminium, 45 steel, POM insulating parts; anodising, black oxide, powder coating
Standard components	MISUMI, Hasegawa and DESTACO toggle clamps; domestic equivalents available to reduce cost
Marking	Laser-etched scales and hole numbering, nameplate, colour-coded inspection points
Delivery documents	3D model, assembly drawing, CMM report, Gauge R&R report, operating manual
Packaging	Wooden case with anti-rust film; lifting holes or castors

5. Quick selection guide

Application	Typical structure	Locating accuracy	Lead time
Hole position gauge	Base plate + locating pins + checking pins	±0.05	5–10 days
Assembly fixture	Base plate + locating + toggle clamps	±0.10	5–7 days
Welding gauge	Thicker base plate + multi-point clamping + copper backing	±0.20	10–15 days
Sub-assembly gauge	Large base plate + datum features + CMM datums	±0.10	15–20 days

Note: the accuracies and lead times above are reference values for standard configurations; the part drawing, tolerance requirements and structural complexity take precedence.

Customisation and service

Beyond the standard structures we build custom tooling from customer part drawings, including quick-change designs, automation interfaces (robot loading, in-line inspection), and digital or sensor-based gauges with data acquisition. We provide a turnkey service covering concept design, design review, machining, assembly and commissioning. Send us your 2D / 3D part drawings and tolerance requirements and our engineers will prepare a proposal and quotation.

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