® Spiral Mill - Thread Inserts NPTF Same insert for internal and external thread 1 2 Insert Size Fig. PitchTPI Ordering code Thread Size Toolholder H13 1 18 H13-18 NPTF 3/8 SRH13... H15 1 14 H15-14 NPTF 1/2 - 3/4 SRH15... H17 1 14 H17-14 NPTF 1/2 - 3/4 SRH17... H23 2 11.5 H23-11.5 NPTF 1"-2" SRH23... H32 2 11.5 H32-11.5 NPTF Int. 11/4"-2"Ext. 1" -2" SRH32... NPS Same insert for internal and external thread Insert Size PitchTPI Ordering code Thread Size Toolholder H13 18 H13- 18 NPS 3/8 SRH13... H15 14 H15- 14 NPS 1/2 - 3/4 SRH15... H17 14 H17- 14 NPS 1/2 - 3/4 SRH17... B04-7