Torx drivers are numbered on a standard series, and the numbers do not describe a dimension you can measure and interpolate. This is the complete list of 12 Torx screwdrivers in the range, by tip size and blade length.
The size series is a lookup, not a scale
Torx sizes step through a defined table of geometries, and the steps are uneven — the jump from one size to the next is small at the bottom of the range and much larger at the top. There is no size between two adjacent numbers, so if a driver rattles in the recess and the next one up will not enter, the screw is not Torx. It is most likely tamper-proof Torx, which has a pin in the middle, or an external Torx head being mistaken for a recess.
Why Torx tolerates abuse that Phillips does not
The driving faces of a Torx lobe are close to perpendicular to the direction of rotation, so torque produces almost no force pushing the driver out. The practical result is that a Torx screw can be driven to its full rated torque with light axial pressure, and can be removed and refitted repeatedly without the recess degrading. It is why the form has taken over on anything designed to be serviced, and why an old Torx screw usually comes out cleanly where an old Phillips does not.
All 12 Torx screwdrivers
| Tip size | Blade length | Handle size | Hex bolster | Teng part number |
|---|---|---|---|---|
| T6 | 75 mm | S | No | MD906TN |
| T7 | 75 mm | S | No | MD907TN |
| T8 | 75 mm | S | No | MD908TN |
| T9 | 75 mm | S | No | MD909TN |
| T10 | 100 mm | M | No | MD910TN |
| T15 | 100 mm | M | No | MD915TN |
| T20 | 100 mm | M | No | MD920TN |
| T25 | 100 mm | L | No | MD925TN |
| T27 | 100 mm | L | No | MD927TN |
| T30 | 100 mm | L | No | MD930TN |
| T40 | 100 mm | L | No | MD940TN |
| T45 | 125 mm | XL | No | MD945TN |
Where this list comes from
Every row is read from the live Teng Tools USA catalogue on the day this page was generated — product record, part number and size taken from the record itself, never transcribed from a printed catalogue or inferred from a pattern. Sizes use the ISO 10664 T designation; Teng marks its Torx tools with a TX prefix and the number is identical. Blade length is read from the product record. A size that has been discontinued disappears from this list rather than lingering as a part number you cannot order, which is the failure mode of every static spec sheet.
When the driver still slips
A Torx driver that slips has almost always lost the tips of its lobes — the six points are the thinnest part of the tool and they wear or shear before anything else. Because Torx does not cam out, the wear happens quietly and the first symptom is a driver that suddenly spins in a screw it used to turn. Check the tip against a known good one rather than blaming the screw, and retire drivers with visibly rounded lobes before they round a recess to match.
Drivers are in screwdrivers; keys and bits are in hex and TX keys.