SUNDERLAND GEAR PLANERS: All Sunderland models worked in the same way and the Company published one excellent general guide together with a limited number of model-specific manuals for other types. Comprehensive 210-page Operator's Instruction Manual and catalogue. Detailed information on: principles of operation for cutting spur, spiral and double helical gears; reference tables and formulae (includes a note about Mold's ratios and demonstrates how to calculate them). Charts showing the changewheels settings for the models 30, 27, 26, 23, 19, 16, 5A, 5B, and  5C. The operating functions of machines with care and adjustment instructions; testing gears, etc. Includes two interesting Sales and Technical Specification Catalogues - one modern, the other older.