A maker’s unusual M42 bolt was cut with separate left-hand and right-hand grooves, so nuts of either handedness can thread onto it. The result is a machining project and fidget toy—not an ordinary bolt that can be tightened either way, or a fastener shown to be suitable for construction loads.
How the bidirectional bolt works
Hackaday’s January 4, 2021 report describes maker Oleg Pevtsov’s bolt as M42 with a 40 mm pitch. Its shaft has grooves cut in both right-hand and left-hand directions. That geometry lets a matching nut of either handedness engage the shaft; the behavior comes from the specially machined grooves, not from a standard bolt feature.
Because the pitch is unusually large, the build did not use one continuous helix for each direction. Instead, the maker cut ten separate grooves per direction to cover the bolt surface. A dial indicator helped maintain accurate spacing while he worked on a manual lathe. For the bolt machining, he used a trimming router mounted in a custom clamp rather than a fixed cutter. The report says it took four attempts to get the bolt right. Hackaday’s project report includes links to videos, but it is not a complete fabrication plan.
What happened when the nuts were used
Pevtsov made three brass nuts: one left-hand, one right-hand, and one bidirectional. Hackaday reports that all three spun down the bolt under gravity alone. The bidirectional nut moved less smoothly than the single-handed nuts and could randomly change both its rotation and its direction of travel.
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The report characterizes the result as a “one-of-a-kind fidget toy.” It suggests that two nuts moving in opposite directions on one lead screw might have practical uses, but does not describe or test a particular application.
Is this a usable construction fastener?
The available report does not establish that. It gives no load testing, tolerances, complete thread profile, bolt material specification, or engineering validation. It also provides no safety procedure or machining feeds and speeds. The unusual geometry and gravity-driven movement are interesting demonstrations, but they are not evidence of strength, durability, or suitability for a structural connection.
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- ✨【Durable to Last】The heavy duty gate latch is made of high quality steel, sturdy and reliable hold. The surface of the black door latch is brushed finish to enhance the rust protection and corrosion resistance, uesd in high temperature or humid environments for a long time.
- ✨【Upgraded Design】Enlarged area bracket used in the bolt latch increases the door fastening force, making the fence gate latch better able to assure your safety. The upgraded bolt length allows deeper insertion into the top frame and bottom door threshold for enhanced stability.
- ✨【Bi-directional Design】DJSUNPACKING slide bolt adopts a very reasonable bi-directional design, can be installed on left and right hand doors, and both left and right hand can use the slide bolt gate latch, suitable for inward and outward swinging gates and doors, provide flexibility and convenience for door lock replacement in every home.
- ✨【Safety Combination】This outdoor door lock with a unique keyhole is suitable for padlocks (padlock not supplied) to add an extra layer of security, making it ideal for applications on doors, gates, and cabinets. Manual closing mechanism prevents children or pets from opening the door, protect the home safety and valuables.
- ✨【Wide Application】Heavy duty gate latch bolts add extra security to your home and protect valuables, widely used in backyards, decks, sheds, baby gates, chicken coop doors, gardens, patios, and barn doors. Indoors, slide bolt latch can be used on interior fences to separate interior spaces and prevent accidents with children, and pets.
For construction or other load-bearing work, use a fastener specified for the application and installed according to its requirements. Do not treat this one-off project as an alternative to a rated bolt.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Could someone reproduce the build?
The report documents selected techniques, including the manual lathe, dial indicator, router, and custom clamp, but not enough information to reproduce the bolt reliably. It does not supply a full drawing or the material and process specifications needed to judge a safe build. The bolt and nuts are described as a one-off project, not as a product for sale.
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