Indexing on a milling machine Which indexing method enables obtaining virtually any number of equal divisions on a workpiece gear/blank, beyond those available with simple plates alone?

Introduction / Context:
Indexing heads allow precise angular divisions for gear cutting and fluting. Some tooth counts cannot be achieved with fixed hole circles and simple ratios.

Given Data / Assumptions:

• Universal dividing head with change gears available.
• Objective: realize arbitrary tooth numbers.

Concept / Approach:
Direct indexing uses a fixed plate, limited to specific divisions (e.g., 24). Simple indexing uses one index plate and crank, limited by hole counts. Compound indexing extends choices via two-hole-circle operations but still finite. Differential indexing gears the index plate to the spindle, creating a small additional rotation that effectively produces almost any division.

Step-by-Step Solution:
Identify tooth count not available on existing hole circles.Set change gears to create the necessary differential motion.Crank turns while plate slowly rotates, yielding the required division.

Verification / Alternative check:
Shop texts list that differential indexing can generate prime numbers like 73 teeth not obtainable by simple plates.

Why Other Options Are Wrong:

• Direct/simple indexing limited by plate holes.
• Compound indexing expands options but still constrained.
• Hand rotary tables lack precise equal divisions without verniers/gearing.

Common Pitfalls:
Incorrect gear train setup causing cumulative error; forgetting to lock the plate properly in non-differential modes.

Final Answer:
Differential indexing