Die Holders & Stocks

Die Holders & Stocks

Die holders — also called die stocks — are the handles used to drive threading dies when cutting external threads by hand. The die sits in a recessed seat in the holder body and is secured by set screws; the operator drives the holder with both hands using the extended handles, applying controlled torque and downward pressure to start and run the die along the workpiece. Selecting the right die holder for the die diameter and the job improves thread quality and reduces the risk of die breakage. AIMS Industrial supplies die stocks and holders for round dies, hex dies, and adjustable die sets.

Types of Die Holders

• Single-handle T-style die stocks: A short, compact design suited to confined spaces. One handle provides less leverage than two-handle designs — appropriate for smaller diameter threads where torque requirements are modest.
• Two-handle die stocks: The standard design for threading operations. Two opposing handles provide balanced torque application, reducing the risk of cross-threading. Available in lengths from 150mm (for small dies, M3–M10) to 450mm and longer for large diameter work (M24 and above).
• Adjustable die stocks: Incorporate an adjusting screw that bears against the split in the die body, allowing the effective cutting diameter to be adjusted. Used to cut threads in multiple passes for better finish on difficult materials, or to adjust for a slightly loose fit where a standard thread would be too tight.

Die Seat Sizes

Die holders are made to accept dies of specific outside diameters. The common standard die ODs in Australia are 20mm, 25mm, 30mm, 38mm, 45mm, and 65mm — each requiring a correctly sized die stock. Using a die in an undersized holder damages the die; an oversized holder does not secure the die correctly. Always match the die stock seat diameter to the die OD.

Material and Build Quality

Professional-grade die stocks are machined from hardened alloy steel with precision ground die seats that locate the die accurately and hold it securely under cutting torque. Economy die stocks with poor die seat accuracy allow the die to rock, producing inconsistent threads.

Cutting Technique

When cutting new threads with a die, apply cutting fluid continuously and back off a quarter turn for every full turn of advance to break the chip. Without chip breaking, the accumulating chip binds in the die and can cause the die to crack or the workpiece threads to tear. The starting chamfer on the workpiece end should be machined or filed to a 45° angle matching the die's lead angle — this helps start the die straight and prevents the first thread from being damaged. For help selecting a die stock for your thread range, contact our team.