Helical coil thread inserts, inch UNC and UNF (Heli-Coil style): drill size, tapped hole, depth for 1D to 3D inserts, #1 to 2 in

sizes

48 in table

Notes

• Inches. The table is Misumi's: thread size (nominal and decimal) and threads per inch, the maximum major diameter the insert tap cuts (the tapped hole into which the coil screws), the drill, and the minimum tapped depth H for insert lengths 1D, 1.5D, 2D, 2.5D and 3D (D = nominal thread diameter, the usual meaning of those lengths). The depth columns are labelled in the source as the minimum tapping depth for each length; each is 0.05 in (small sizes) to 0.1 in or more above the insert length, which is consistent with a hole that is a little deeper than the insert.
• Drills are given as number, letter-free fraction or fraction exactly as Misumi prints them (no decimal equivalent is printed; none is supplied here). The metric DIN 8140 sizes are on helical-thread-inserts-din-8140 (M3 to M16).
• Check: the Albany County Fasteners STI chart (a stainless-insert system, #4-40 to 3/4-16) prints different drills for some sizes (for example #3 for 1/4-20, where Misumi's coil insert drill is 17/64) and one minimum-depth column, so it is not merged here. Use the maker's chart for the insert you buy; free-running and locking versions of the same insert use the same drill.
• No files: the coil is a helix whose wire section is not published as numbers in the table read. McMaster-Carr sells mil-spec helical inserts with per-part STEP; linked, not copied.

Helical coil thread inserts, inch UNC and UNF (Heli-Coil style)… size chart

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Plain text: sheet.txt · JSON: /api/geometry?object=helical-thread-inserts-inch-unc-unf

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