What are Die Stocks?

What are Die Stocks?

Die stocks are the hand tools used to hold and drive circular dies during manual external threading operations. Also referred to as a die holder, die handle, die stock wrench, die tap handle or tap and die handle, a die stock seats a circular die securely within its body and provides the extended handles needed to apply controlled rotational torque, cutting clean, accurate external threads on rod, bar, studding and other cylindrical workpieces. 

Accu stocks die stocks across two standards: the circular split die stock to BS1127 and the circular solid die stock to DIN223. Both types feature knurled handles for secure grip under load and are built with the rigidity needed to produce consistent, accurate threads in workshop and field environments.

How Die Stocks Work

A die stock works by seating a circular die in its body cavity and locking it firmly in place using retaining screws. The operator holds the extended handles on either side and rotates the die stock wrench around the workpiece, advancing it incrementally to cut the external thread. A short reverse rotation after each forward pass breaks the chip and clears swarf from the cutting faces, reducing the risk of die binding or thread damage.

For example, a maintenance engineer re-threading a damaged stud on a hydraulic manifold would use an appropriately sized metric coarse die in a DIN223 solid die stock, remembering to apply cutting fluid and advance the stock in controlled half-turn increments, reversing between each pass to clear chips. This gives a cleaner finishing cut, producing a full-form thread without overloading the die.

Materials Die Stocks Are Made From

Accu's range of die stocks is manufactured from the material best suited to the mechanical demands of heavy-duty threading work.

• Steel: Both the BS1127 and DIN223 die stock bodies and handles are constructed from steel throughout, providing the rigidity and torsional strength needed to transmit threading torque without flex or distortion. Knurled surfaces on the handles improve grip security during high-torque threading operations.

Size and Type Of Die Stocks Available

To cover the range of standard circular dies used in manual threading, Accu's Presto die stocks are available in:

• Die Stock Type: Circular split die stocks to BS1127 (3 retaining screws, adjustable) for use with inch-OD circular split dies and circular solid die stocks to DIN223 (4 retaining screws) for use with metric solid circular dies.
• BS1127 Holder ODs: 13/16", 1", 1-5/16", 1-1/2", 2", 2-1/4", 3" and 4", covering the full range of standard inch-OD circular split dies.
• DIN223 Holder Sizes: M20, M25, M30, M38, M45 and M55 (diameter x depth variants available within each size), covering metric solid dies from small to large thread diameters.

This selection covers the die stock requirements for the full Accu range of circular dies, from small-diameter metric threading through to large imperial and heavy-duty applications.

FAQs

Q: What tool is used to hold a die?

A: A die stock is the tool used to hold a circular die during manual external threading operations. It secures the die within its body using retaining screws and provides extended handles that allow the operator to apply the rotational force needed to cut an external thread. 

Q: What size die holder do I need?

A: Match the die holder to the outer diameter of the circular die you are using. BS1127 die stocks are sized in inches (13/16", 1", 1-5/16" and so on) and accept dies with the corresponding inch OD. DIN223 die stocks are sized in metric (M20, M25, M30 and so on) and accept solid circular dies of the matching OD. 

Using an incorrectly sized die in a die handle tool risks the die seating unevenly, producing off-pitch threads and potentially damaging the die face.

Q: What is the difference between a BS1127 and a DIN223 die stock?

A: The BS1127 standard covers adjustable die stocks sized for circular split dies with inch outer diameters, from 13/16" to 4". Three retaining screws lock the die in place and allow the cutting diameter to be varied: the centre screw opens the die for a roughing pass and the outer two close it for a finishing cut. 

The DIN223 standard covers solid die stocks sized to metric outer diameters (M20 to M55), using four screws for die retention only. These metric holders suit the fixed-diameter solid circular dies produced to that standard.

Q: Can I use a split die in a solid die stock or vice versa?

A: No. BS1127 adjustable die stocks are designed specifically around the three-screw adjustment system that works with circular split dies and their die cavity dimensions match BS1127 inch OD sizes. DIN223 die stocks are dimensioned for solid metric dies to the DIN223 standard. 

Mixing standards risks the die not seating squarely, which compromises thread quality and risks damage to the die or workpiece.

Q: What lubricant should I use when threading with a die stock?

A: Cutting fluid or threading oil should be applied to the workpiece before and during the threading operation. General-purpose cutting fluid suits mild steel and most common metals. A sulphurised threading oil is better suited to tougher alloys and stainless steel. Aluminium and non-ferrous metals typically require a lighter lubricant such as WD-40 or paraffin. Adequate lubrication extends die life, improves thread surface finish and reduces the effort required to advance the die stock through each pass.

Bespoke Die Stocks Manufacture.

High precision, bespoke manufacture of Die Stocks to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.