Left Pedal Reaming Tap

When a left-hand pedal thread is past the point where chasing will recover it; stripped, partially cross-threaded, or torn out at the entry; the crank arm isn't done. The Left Pedal Reaming Tap 1695.1AL cuts the failed thread away, enlarges the hole, and cuts a new thread sized for the Left Pedal Thread Insert 1695.4A. Insert installed, the crank takes any standard 9/16" pedal again.

The "left" matters. Bicycle left-hand pedals use a reverse-threaded engagement (the left pedal threads counterclockwise to tighten). The reaming tap has to match that geometry, which is why the 1695.1AL is sized and threaded specifically for the left-hand pedal hole. The right-hand version is the 1695.1AR.

How the reaming process works

The reaming tap is two tools in one shank. The leading section is a reamer that cuts away the existing (damaged) thread profile and enlarges the hole to a precise oversize diameter. The trailing section is a thread tap that cuts a new thread pattern in the freshly enlarged hole, sized to accept the pedal thread insert.

Mate the 1695.1AL to the Handle for Pedal Taps 1695/4BI for the leverage to cut cleanly through aluminum. Hold the tap perpendicular to the crank face during the first turn; the rest of the cut follows the established line, but the first turn sets the geometry.

After the new thread is cut, install the Left Pedal Thread Insert with a strong thread locker. The insert's outer thread engages the freshly cut thread in the crank; the insert's inner thread is standard 9/16" × 20 TPI (left-handed) ready to accept any standard pedal.

What this is NOT

The reaming tap is for stripped threads that need a new thread pattern cut. It is not the right tool for cleaning up existing threads; that's the Pedal Tap Set 1695.1.

Specs

• Left-hand reaming and thread-cutting tap
• Cuts a left-hand 5/8" × 24 TPI oversize seat thread; the finished insert restores the standard 9/16" × 20 pedal thread
• Square-shank engagement, compatible with 1695/4BI Handle for Pedal Taps
• Pair with Left Pedal Thread Insert 1695.4A
• Article number: 1695.1AL

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. The 1695 reaming-tap and thread-insert system was developed by Unior specifically for the cycling repair trade; most thread-rescue inserts on the market are general-machinery Heli-Coils that don't fit pedal-thread geometry. The 1695-series inserts are sized for the pedal thread, which makes the rescue cleaner and more durable.

Pro tip from our mechanics

Pedal-thread rescue is the kind of repair that wins customer loyalty. The customer expects to replace the crank; the shop that saves it instead is the one they remember. Our workshop hand tools guide walks through the complete pedal-thread workflow and the rest of the workshop tool layer: Workshop hand tools every bike shop needs →

FAQ

Why is there a separate tap for the left crank arm? Left pedals sit on a reverse (left-hand) thread that tightens counterclockwise, so a tap's cutting geometry has to be handed. The 1695.1AL reams and cuts left-hand threads only; the drive-side arm takes the 1695.1AR. Neither tap can stand in for the other, and a shop rescuing both arms needs the pair.

Which direction do I turn the 1695.1AL to cut? Counterclockwise, following the left-hand thread it cuts. Start with the reaming section square to the crank face; the angle of the first turn is the angle the finished thread follows. From there keep steady pressure, use cutting fluid on aluminum, and back the tap off a part-turn now and then to break chips.

What else do I need to complete a left pedal thread repair? Three things finish the job: the 1695/4BI tap handle, which drives the tap's square shank; a 1695.4A left thread insert, which screws into the freshly cut 5/8" × 24 seat; and thread locker to fix that insert in the arm. Once the insert is set, the arm accepts any standard 9/16" × 20 left pedal.

Can the tap restore the original 9/16" thread without an insert? No. The stripped metal is gone, so the 1695.1AL deliberately cuts an oversize 5/8" × 24 seat rather than re-cutting the 9/16" × 20 standard. It is the 1695.4A insert threaded into that seat that carries the new pedal thread, which is why inserts belong in the same order as the tap.