Straight Edge Surface Plate RT-1200 - 50 inches (1270MM)

A straight edge surface plate is used to measure the flatness of cylinder heads and engine blocks after resurfacing. It's an essential tool to verify if the surface is perfectly flat, without warping or unevenness. The RT-1200 Chinelatto measures with millimetric precision, ensuring the cylinder head will seal properly at the gasket. Without this verification, you can get blown head gasket problems, overheating and oil-water mixing in the engine.

The RT-1200 straight edge is 50 inches (1,270mm) long, 2 inches (50mm) wide and 3.3 inches (85mm) high, weighing 29.3 lb (13.3kg). These dimensions allow measuring cylinder heads from large engines like V8s, truck diesel engines and tractors. It's made from normalized GG-25 cast iron with double T format, ensuring structural rigidity. The surface is ground for maximum precision in flatness verification.

The 50-inch (1,270mm) straight edge is ideal for large engines: V8s from classic cars, truck diesel engines, agricultural tractors, industrial generators and marine engines. The length of over 3 feet allows measuring long cylinder heads that smaller straight edges cannot verify completely. The RT-1200 Chinelatto serves machine shops working with heavy vehicles and industrial equipment, where flatness precision is critical.

Cast iron straight edges like the RT-1200 are more dimensionally stable than steel straight edges, don't warp with temperature variation in the shop. GG-25 cast iron absorbs vibrations better, giving more precise readings. Steel straight edges are lighter but can flex under their own weight at large lengths. The ground surface of cast iron maintains precision longer, requiring fewer recalibrations.

Place the RT-1200 straight edge on the clean cylinder head surface, supporting at the ends. Use feeler gauges or dial indicator to measure clearance between the straight edge and head surface. Measure at several points: diagonal, longitudinal and transversal. If clearance exceeds the limit specified by engine manufacturer (usually 0.002 to 0.006 inches), you need to resurface the head. The ground surface of the straight edge ensures perfect reference for measurement.

The RT-1200 straight edge needs to be stored in dry location, protected from impacts and corrosion. Always clean after use with dry cloth and apply light oil against rust. Avoid placing weight on it or using as support for other parts. The ground surface can last decades with proper care. If it loses precision, it can be re-ground by specialized company. The GG-25 cast iron is resistant to normal shop wear.