TrigJig RSA300 LE Adjustable Rafter Square

• Product: TrigJig RSA300 LE Adjustable Rafter Square

• Target Trade: Timber Framers, Roofers, Commercial Builders, Carpenters

• Core Innovation: A smart adjustable fence running on nylon 66 bearings, paired with deep-engraved scales to eliminate layout drift on large structural timber.

• Best 300mm adjustable metric rafter square for heavy timber framing, repetitive roof trusses, and permanent anti-wear layout.

The TrigJig RSA300 LE Adjustable Rafter Square delivers absolute layout accuracy for heavy timber framing and complex roofing projects. Precision CNC-machined in Great Britain from high-quality T6 European aluminium, this massive 300mm metric square features a smart adjustable fence that locks securely in position for rapid, repeatable truss marking. Driven by ultra-smooth nylon 66 bearings, the fence snaps back to exactly 0°, guaranteeing an extreme right-angle precision of +/- 0.008° along its entire length.

The Pro's Equation: Eliminating Drift on Large Timber

In large-scale timber framing, measurement drift translates directly into catastrophic material waste and time-consuming rework. Standard oversized squares often suffer from faded printed markings and rigid setups that slow down production. The RSA300 LE eliminates these profit-killing variables completely. By integrating CNC deep-engraved degree lines and recessed laser-marked graduation rulers, the critical scales are permanently protected against job site abrasion. Paired with curved scribe notches specifically tailored for common timber sizes, this "set and forget" precision instrument accelerates repetitive cuts, ensuring every mark is dead-on and providing a massive, lifetime return on investment (ROI) for professional tradesmen.

Why Pros Choose the TrigJig RSA300 LE:

• Adjustable Fence System: "Set and forget" mechanism with smooth nylon 66 bearings for rapid, repeatable truss layouts.

• Permanent Precision: CNC deep-engraved degree lines ensure markings will never rub off, even on rough structural timber.

• Recessed Rulers: Laser-marked scales sit inside shallow pockets, preventing contact with the workpiece and avoiding surface abrasion.

• Massive 300mm Capacity: Purpose-built for large trusses, heavy timber, and commercial roofing calculations.

• Zero-Play Accuracy: CNC-machined to an extreme tolerance of +/- 0.008°, snapping back to absolute zero instantly.

Does the adjustable fence lose accuracy when returned to zero?

No. The fence operates on highly durable nylon 66 bearings and is fully CNC-machined. This ensures that when the fence is unlocked, it snaps back to exactly 0° with a strict +/- 0.008° precision, completely eliminating any mechanical slop or layout drift.

Will the measurements rub off when sliding across heavy, rough timber?

Absolutely not. The degree lines are CNC deep-engraved directly into the aluminium, and the graduation rulers are laser-marked inside shallow recessed pockets. This advanced anti-wear engineering ensures the scales never physically scrape against the timber, permanently preventing abrasion.

Is this square large enough for commercial timber framing?

Yes. With a massive 300mm length and built-in rafter/rise tables, this square is specifically engineered as a heavy-duty solution for working with large timber, roof trusses, and oversized structural framing where a standard 180mm square is simply insufficient.