300 mm machinist combination square — 90° right angle, 45° mitre, spirit level, and scriber pin in one precision instrument for marking out and measurement.
A combination square is a versatile marking-out and measurement instrument consisting of a hardened, graduated steel blade and a sliding head that clamps at any position along the blade. The standard combination square head provides a 90° reference (right angle), a 45° reference (for mitre and chamfer marking), an integrated spirit level (for checking plumb and level), and a steel scriber pin stored in the head for scribing reference lines on metal. Together, these functions replace four separate tools with a single compact instrument that fits in an apron pocket.
Machine shops in Guwahati's industrial areas — making components for the tea, oil, and hydro industries — use combination squares daily for marking out workpieces before machining, checking machined faces for squareness, setting up milling vices, and scribing witness lines on shaft ends. Fabrication workshops use them to mark cut lines on structural sections and check weld joint perpendicularity. Woodworking shops making furniture and wooden formwork for concrete use combination squares for marking tenons, halving joints, and mitre cuts.
Toolroom machinists and centre lathe operators use the 300 mm combination square to set up turned components for marking off before milling or grinding operations. Sheet metal fabricators use them to mark out blank development layouts and check that folded flanges meet at 90° or 45° as designed. Maintenance engineers working on compressor skids, pump bases, and motor alignments use the spirit level function to check levelness before bolting down equipment.
Engineering draughtsmen and fitters in ONGC's Assam fields, NEEPCO's hydro projects, and tea estate workshops rely on combination squares for daily marking-out work. Carpentry contractors use them for timber frame squareness checks, beam-end marking, and door-frame setting. Site supervisors carry them for quick right-angle checks on masonry openings before glazing or door installation.
The combination square complements digital vernier calipers and micrometers for complete workpiece inspection. It pairs with marking blue (Prussian blue) or scriber fluid for visibility of scribed lines on bright metal surfaces.
| Category | Measuring Tools |
|---|---|
| Key specs | 300 mm, machinist set |
| Blade length | 300 mm (standard machinist set) |
| Features | 90° square, 45° mitre, spirit level, scriber |
| Head | Cast iron, sliding and lockable |
| Availability | In stock — price on request |
A combination square has a sliding, lockable head on a ruled blade, allowing it to measure lengths along the blade at any position — not just at the end. The head includes a 90° square, a 45° mitre reference, a built-in spirit level, and usually a scriber pin. A standard try square only provides a fixed 90° reference at the blade end with no measurement scale. The combination square is therefore more versatile for marking out, depth measurement, 45° chamfer scribing, and surface flatness checks — four tools in one compact instrument.
The combination squares we stock are machinist-grade instruments with ground and hardened steel blades. The square function is accurate to within 0.01–0.02 mm per 100 mm, sufficient for marking-out in machine shop and fabrication work. For precision grade (optical quality toolroom standard), a Grade A precision square is the appropriate choice. If you need a traceable calibration certificate for your quality system, we can arrange calibration services in Guwahati. Call or WhatsApp our measuring tools counter for availability.