Internal Threading tool: Threading tool includes external and internal threading tools External threading tools' applicable inserts: TT11--. TT16--, TT22--. Internal threading tools' applicable inserts: LT11.01N-GM, LT16.01N-GM, RT11.01N-GM, RT16.01N-GM The characteristic of Internal threading tool: We have standard threading tools in stock and we can also design and produce the non-standard tools in 10-20 days. External threading tools, Internal threading tools, parting off blade and block, cutting & grooving tools.