Hirobo HI2539018 Hexagon Button Bolt M3 x 25 for RC Helicopter Applications  [HI2539018]

Compact Button-Head Hex Bolt

This M3 x 25 hexagon button bolt is intended for use in RC helicopter builds and related small-model connections. The low-profile head helps prevent snagging and is suited to locations where space above the head is limited.

Fit the bolt with a matching hex driver, hand-align the threads to start, and apply restrained torque to protect M3 threads in lightweight parts. For joints that need extra resistance to vibration, a small amount of low-strength threadlocker may be applied, keeping future serviceability in mind.

Used correctly, these bolts maintain joint alignment and reduce unwanted movement. Include them in post-assembly checks and routine inspections to keep model handling consistent and reliable.