noscriptThreading Dies | HSS Dies | Cromwell Tools


Produce flawless external screw threads with BSW dies designed by expert brands Dormer and Sherwood. With over 20 thread sizes to choose from and various thread pitches at your disposal, you can be sure that you'll be adding quality dies to your toolkit whenever you choose our BSW dies.

Whether the threading job needs to be done by hand or machine, at Cromwell, we've made sure that the thread size you need is right on our shelves so you can start the work without wasting any precious time. All the BSW dies in our range are made from high-speed steel to ensure durability, no matter the material you're using them for.

Don't forget to check out our full range of thread dies for even more thread standards, including BSF thread dies and UNF HSS dies. If it's the matching BSW tap you're looking for, we've got you covered as well.

What are threading dies?

In simple terms, dies perform the opposite task to taps. Where taps produce female threads dies create threads on fastener such as screws, bolts and other components. They can also be used to rethread damaged threads that have worn out over time.

Types of threading dies

Threading dies come in many shapes and sizes, the most common being round, square, hexagon or tubular. These can also be categorised by solid, split, and separable.

Split - split dies are adjustable and used in the threading of precision fasteners as well as cleaning up and repairing external threads. These dies are used in a die stock which locks into the die and is turned with its dual handles to create the thread.

Hex - Referred to as a hex nut die, these dies can be used in regular wrenches to turn the die and carve out the thread. They are often used as a chaser or to repair worn or damaged threads.


How do I use a threading die?

Depending on what type of die you are using the methods vary but only a little. With circular or split dies they will be turned using a die-stock, a t-handle style too that locks the die in place and uses the dual handles to generate a turning force that cuts the thread into the material. With hex nut dies a spanner or wrench is used to turn the die carving the thread into the surface. In both cases cutting oil should be used to lubricate the surfaces.