Threading Dies: what Claude and GPT would buy
Two AI models chose on their own, with no web access. Nobody tested these products: this is what each one says, and how to check it.
They disagree: Claude chooses Drill America and GPT chooses IRWIN
In Industrial & Scientific, Claude and GPT choose the same brand in 52 of 107 categories.
Claude Opus 5.5 · October 28, 2026
Drill America (brand)
Drill America sells individual high-speed-steel dies in a wide spread of inch and metric sizes, so you can buy the exact thread you need instead of a mixed set full of sizes you won't use.
Not for: Production shops cutting tough alloys all day, who should buy premium dies from established threading-tool makers.
GPT 6.1 Sol · November 10, 2026
IRWIN HANSON (line)
A practical choice for occasional external-thread cutting and repair, with common sizes available. Match the die to your required diameter and pitch.
Not for: High-volume production or hardened steel without checking the specific die’s suitability.
Claude also picks IRWIN for “chasing damaged threads with a wrench”.
Which one fits you
chasing damaged threads with a wrench
Irwin Hanson (line)
Hanson hex dies are widely stocked in single sizes and turn with an ordinary wrench or socket when there's no room for a die stock.
Not for: Anyone cutting new threads on hard steel who needs an adjustable fit.
adjustable round dies for a die stock
Union Butterfield (brand)
Union Butterfield is an established maker of split, adjustable high-speed-steel round dies used in machine shops.
Not for: Occasional DIY users who only need to clean up an existing thread.
Check before you buy
Where to find Drill America
- Drill America
- The Home Depot
- Bayou Tool
Shops seen in search results on November 6, 2026. A shop missing here may sell it too. Nothing was checked by a person.
Brands that matter
- Irwin Hanson: The most commonly stocked hex and round dies for general repair work.
- Drill America: Broad single-size HSS selection in both inch and metric.
- Union Butterfield: Industrial adjustable round dies.
- Greenfield Threading: Long-standing threading-tool maker, including two-piece dies.
- OSG: Premium threading tooling, known mainly for taps.
- Gyros: Precision tooling for small and fine threads.
What to avoid
- Large unbranded mixed tap-and-die sets made of soft carbon steel if you thread steel.
- Starting the die from the unchamfered face.
- Cutting dry on steel; use cutting oil and back the die off every turn or so to break the chip.
- Buying a die before checking that its outside diameter fits your die stock.
Questions
Hex or round die?
Hex dies turn with a wrench and are best for cleaning up existing threads in tight spots. Round dies in a die stock are better for cutting new, straight threads.
Why won't the die start?
The tapered (chamfered) side must face the work, and the rod end should be lightly chamfered so the die can bite.