Proxxon HSS Internal Threading Tool Set — 6-Piece, Metric & Whitworth, 6mm Shank in Wooden Box (No. 24520)

Cut internal threads in both metric and Whitworth standards. The Proxxon HSS internal threading tool set provides six boring cutters covering the two most common thread forms — 60° metric and 55° Whitworth — in three sizes each, giving you the flexibility to cut a wide range of internal thread sizes on the lathe. All six cutters are presented in a fitted wooden box and mount via a tool holder to the tool post of the PD 230/E lathe.

What's Included

60° Metric inside thread cutters (3 pieces):

• 3/64" (1.3mm) — for fine metric threads
• 7/64" (2.65mm) — for medium metric threads
• 5/32" (4.0mm) — for larger metric threads

55° Whitworth inside thread cutters (3 pieces):

• 3/64" (1.3mm) — for fine Whitworth threads
• 7/64" (2.65mm) — for medium Whitworth threads
• 5/32" (4.0mm) — for larger Whitworth threads

Key Specifications

• Pieces: 6 cutters (3 metric + 3 Whitworth)
• Thread angles: 60° (metric) and 55° (Whitworth/BSW)
• Shank diameter: 15/64" (6mm)
• Cutter length: 3-3/16" (95mm)
• Material: HSS (High Speed Steel)
• Compatible machine: Proxxon PD 230/E (via tool holder mounted to tool post)
• Storage: Fitted wooden box
• Part No.: 24520

Metric vs. Whitworth — Which Do You Need?

The 60° metric thread form is the international standard used in most modern engineering applications. The 55° Whitworth (BSW) form is the British standard, still widely used in older machinery, vintage equipment restoration, and some specialty applications. This set covers both, making it suitable for a broad range of threading work.

Frequently Asked Questions

Which lathe is this compatible with?
These cutters are designed for the Proxxon PD 230/E lathe, mounted via a tool holder to the tool post. Verify compatibility with other Proxxon lathe models before ordering.

Is a tool holder included?
No — the cutters require a tool holder that mounts to the PD 230/E tool post, sold separately.

What's the difference between boring and threading tools?
These are specifically internal threading (boring) tools — they cut thread forms inside a pre-bored hole. They are not general-purpose boring bars for enlarging holes.

Works Well With

• Proxxon Precision Lathe PD 250/E — similar Proxxon lathe ecosystem (verify PD 230/E compatibility)
• Proxxon Tungsten Carbide Insert Cutter Set for PD 250/E (No. 24555) — carbide turning tools for the Proxxon lathe range
• Proxxon Die Holder for Round Dies — M3 to M10 (No. 24082) — external threading companion for cutting outside threads

Returns can only be accepted for unused product in its original packaging. A copy of the original packing slip or invoice is required. For warranty claims please call 1-877-776-9966. Please see our return and refund policy here.

WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.