*ST - Standard Inserts - Cutter Diameter of the Tool = STANDARD Used for Fine Pitches only: 40UN - 10UN and M1.0 - M2.75 *OS - Oversized Inserts - Cutter Diameter of the Tool = OVERSIZE Used for Coarse Pitches: 9UN - 4UN, M3.0 and Up, and All Tapered Forms
Minimum I.D. Thread recommended for STANDARD Pitches ONLY!!! For Large Pitches in internal applications double check tool cutter diameter and minor diameter for proper clearance. TECH TIP Minimum size threads are, by default, listed in this catalog to 'standard pitch inserts.' Please keep this in mind when picking an Advent Tool; especially for your I.D. thread form. Too large a cutter diameter relative to the minor diameter of your thread form will have adverse effects on every aspect of your thread/form milling operation(s). For example, a #125-TA-78-F3 tool loaded with 12 pitch inserts has a cutter diameter of 0.970". The same tool loaded with 8 pitch (or even tapered form inserts) has a cutter diameter of 1.100"! In cases like these, with your minor diameter in mind, you may opt to choose a smaller diameter Advent Tool: But by all means contact us or your local representative for guidance!