Left-hand thread sets for internal and external threads
Left-hand threads sit where the direction of rotation in service would otherwise undo a joint: on left wheel studs, turnbuckles, shaft ends, gas fittings. Right-hand tools destroy them. These four sets cover the common range from M 3 LH to M 20 LH, for internal and external threads.
The four compositions
- Hand taps, 23 pieces with ratchet, M 3 LH to M 12 LH. Internal threads only, but with a drive for tight spots.
- Hand taps and dies, 43 pieces, M 3 LH to M 12 LH, tapping drills included. The complete set for internal and external threads.
- Hand taps and dies, 52 pieces, M 3 LH to M 20 LH. The same build with a wider range.
- Dies, 19 pieces with guides, M 3 LH to M 12 LH. External threads only; the guides keep the die square to the bolt.
What to watch when cutting
The tool turns anticlockwise. That feels wrong when starting, and the short backward turn that breaks the chip then goes clockwise. Nothing changes for the tapping drill, the same table applies as for right-hand threads. What matters is marking tool and workpiece clearly, so that nobody later starts with the wrong direction.
How to spot a left-hand thread on a component is shown in Identify and cut left-hand threads correctly. Single left-hand tools are under hand taps, machine taps and round dies, each in its own left-hand subcategory.
