Threaded Insert Size Chart
A quick reference for the thread sizes used with threaded inserts, insert nuts and tee nuts in furniture, cabinet and fixture work, with the sizes Supply Tie stocks linked. Any size or style not listed as stocked can be quoted by the box or case.
Choosing an insert? Read how to size a threaded insert: thread, length, material and style.
How to size a threaded insert
- Thread size is the bolt or machine screw the insert accepts, for example 1/4-20 (1/4 in. diameter, 20 threads per inch) or M6 x 1.0 (6 mm diameter, 1.0 mm pitch). Match it to the screw you will use.
- Coarse vs. fine. Coarse threads (UNC) are the default for inserts in wood and particleboard. Fine threads (UNF) are mostly used in metal.
- Inch and metric do not mix. M6 is close to 1/4 in. and M8 is close to 5/16 in., but the threads will not engage properly. Use the same system as the screw.
- Length should be at least as long as the screw engagement you need, and shorter than the material is thick.
- Hole size depends on the insert style (screw-in, press-in, flanged or tee nut) and the material. Use the maker's spec for the exact insert; we include it with every quote.
Inch thread sizes
| Size | Coarse (UNC) | Fine (UNF) | Major diameter | Diameter (mm) | Stocked tee nuts | Matching threaded rod | Other styles |
|---|---|---|---|---|---|---|---|
| #6 | #6-32 | #6-40 | 0.138 in | 3.5 mm | — | — | Quote #6 inserts |
| #8 | #8-32 | #8-36 | 0.164 in | 4.2 mm | — | — | Quote #8 inserts |
| #10 | #10-24 | #10-32 | 0.190 in | 4.8 mm | Hillman #10 tee nut |
10-24 threaded rod 10-32 threaded rod |
Quote #10 inserts |
| 1/4 | 1/4-20 | 1/4-28 | 0.250 in | 6.35 mm | Hillman 1/4 in. tee nut, 100 pk | 1/4-20 threaded rod | Quote 1/4 inserts |
| 5/16 | 5/16-18 | 5/16-24 | 0.3125 in | 7.94 mm | Hillman 5/16 in. tee nut, 100 pk | 5/16-18 threaded rod | Quote 5/16 inserts |
| 3/8 | 3/8-16 | 3/8-24 | 0.375 in | 9.53 mm | Hillman 3/8 in. tee nut, 100 pk | 3/8 in. threaded rod | Quote 3/8 inserts |
| 1/2 | 1/2-13 | 1/2-20 | 0.500 in | 12.7 mm | — | 1/2-13 threaded rod | Quote 1/2 inserts |
Metric thread sizes
| Size | Coarse pitch | Diameter in inches | Nearest inch size | Stocked inserts | Other styles |
|---|---|---|---|---|---|
| M4 | M4 x 0.7 | 0.157 in | close to #8, not interchangeable | — | Quote M4 inserts |
| M5 | M5 x 0.8 | 0.197 in | close to #10, not interchangeable | — | Quote M5 inserts |
| M6 | M6 x 1.0 | 0.236 in | close to 1/4 in, not interchangeable |
Cabineo M6 x 12.3 mm insert nut, 100 Cabineo M6 x 12.3 mm, 500 Cabineo M6 x 15.3 mm, 100 Cabineo M6 x 15.3 mm, 500 Lamello Cabineo inserts are hammer-in steel sockets made for Cabineo M6 connector screws: 12.3 mm for 14-16 mm panels, 15.3 mm for 17-25 mm. |
Quote M6 inserts |
| M8 | M8 x 1.25 | 0.315 in | close to 5/16 in, not interchangeable | — | Quote M8 inserts |
| M10 | M10 x 1.5 | 0.394 in | close to 3/8 in, not interchangeable | — | Quote M10 inserts |
| M12 | M12 x 1.75 | 0.472 in | close to 1/2 in, not interchangeable | — | Quote M12 inserts |
Get a quote on other inserts
Send the thread size, insert length, the material it goes into (hardwood, particleboard, MDF, plywood or metal) and the style you use now (screw-in, press-in, flanged or tee nut) on the threaded insert quote form. We quote by the box or case and usually reply within 1 business day.