Among excellent makers of allen wrenches (think: Bondus, Allen, PBSwiss, Pedro’s, Park, Wihus, and others) only one has addressed engagement geometry like external socket wrenches have.
Historically, allen screws arose for embedded fasteners. The wrench inserts into a fastener rather than surrounding it. But the hexagonal interfaces have similar limits. In order to transmit maximum torque to a fastener without deformation drive shape was devised for external sockets, often known as “flank drive.” That name belongs to Snap-On, a socket drive pioneer but you’ll find such drive geometry everywhere today.
As this idea is nearly universal for external socket wrenches, why are internal allen wrenches all plain hex shapes driving on their corners? As allen screws dominate in bicycles, we need to ask about this situation!
Damaging or stripping out the screw is a real threat. All of us have seen bad fits (slightly undersized wrenches, slightly oversize screws) and bad materials (less hard wrenches and screws of softer metals). External drive wrenches on hex heads see far less trouble. How can the allen screw interface be improved?
If the faces of an internal drive wrench are subtly modified, over 20% more torque can be applied before deformation. Experience with Wera tool geometry has made me a believer. The difference is real and important.
I challenge you to test this. As smaller size wrenches seem to exaggerate the effect, try testing with 2, 2.5, or 3mm wrenches. Overtighten sacrificial screws with various wrenches and notice the obvious difference. Or enjoy this excellent test by Matt Fields.
It’s time to benefit from this trick. Wera is well distributed but you won’t see it in many channels. We’ve decided to offer Wera L-keys but the least expensive model with total function—steel, black laser, long L, ball point, from 2mm – 10mm, selling from $0.90 to $5 each.
As you build your box and workshop, color is an important option. You can decorate tools with vinyl dip or tape, buy pre-colored models, or use shrink tubing. They all work but shrink tubing is my preference. Color choice can be artistic, functional, or individual.
- Artistic—try World Championship colors: white, green, yellow, black, red, and blue.
- Functional—give each size a different color. So your L-keys are faster and easier to retrieve.
- Individual—make all your L-keys one color, different from your work mates. When all yours are yellow, for example, chances are lower your tool ends up in their box.
To empower this fun and games, we now sell 12″ (30.5cm) lengths of shrink tubing in six colors and diameters to fit 2-10mm wrenches. For a modest cost you can decorate, repair, change, and play. Shrink tubing is tough, tactile, and slightly rounds the hex key center for ease of turning. One foot of shrink tubing will make many short sections for a bunch of wrenches. A standard heat gun does the shrinking.
Please share your solutions. Toolbox Wars can now move beyond foam cut inserts and factory anodizing.