JAPAN SKC ROUND DIE - No: 819 UNF

More info

The SKC Japan Round Die No. 819 is designed for UNF (Unified National Fine) threads.¹ Like the other numbers in the SKC series, this identifies the adjustable round split die specifically for "fine" pitch American/Unified threads.

Technical Specifications

Thread Standard: UNF (Unified National Fine).² These have a 60° thread angle and more threads per inch (TPI) than standard "Coarse" (UNC) threads, providing higher strength and better vibration resistance.
Model Number: No. 819 (Unified Fine Series).³
Material: SKS (Alloy Tool Steel). These are hardened for durability and are intended for hand-threading or re-threading in metals like steel, brass, and aluminum.
Adjustment: Split Die Type. Features a side slit and a small adjustment screw to allow for precision sizing of the thread.

Common No. 819 UNF Sizes

Because "No. 819" covers the entire UNF range, the physical size of the die depends on the thread you are cutting. Here are the most common configurations:

Thread Size (inch)	TPI (Fine)	Outside Diameter (OD)
1/4"	28	1" or 1-5/16"
5/16"	24	1" or 1-1/2"
3/8"	24	1" or 1-1/2"
1/2"	20	1-1/2"
5/8"	18	1-1/2"
3/4"	16	1-1/2" or 2"
1"	12	2" or 2-1/2"