The A3 Delta is TEKTO's side-opening automatic: a 3.60-inch titanium-coated D2 drop point that swings out at the press of a button, locks with a button lock, and stays closed under a safety switch, in a contoured G10 or forged carbon handle at 5.96 ounces. It is the knife we point gloved hands to, the one friends at a local Air Force Reserve unit helped us refine, and the full-size automatic for people who want a blade that opens like a folder instead of firing out the front. Here is how it works, what it is made of, who it suits, where it is legal, and how it compares with the A5 Spry and the A3 Delta Mini.
The Short Version
Pick the Delta over an OTF when you want a bigger button, a bigger handle and a blade that pivots open the way a folder does, with the speed of a spring. It is the heaviest automatic in the line, and the weight is the point: a 5.20-inch handle with texture and jimping where the fingers land, a 3.60-inch blade with a full grip behind it, and a safety switch so the knife never opens in a pocket. The handle comes in black, desert or OD green G10 or in forged carbon, the blade comes plain or serrated, and the A3 Delta Mini shrinks the same mechanism to 1.90 inches for the states with a 2-inch line.
How a Side-Opening Automatic Works
An OTF fires its blade straight out of the front of the handle on a track. A side-opening automatic keeps the blade on a pivot, like a folder, and a spring behind the pivot throws it open when the button releases it. The blade swings through the same arc a flipper would, in a fraction of the time, and the button lock catches it at the end. Pressing the same button lets the blade swing back, so the knife opens and closes with one thumb. The advantage over an OTF is a full-depth blade with a conventional pivot, which means a stronger lockup under side load and no blade play, and a button large enough to find without looking. The trade is that the blade swings open past the hand on the way out, which the safety switch and a little habit take care of. Our types of switchblades guide covers every automatic mechanism side by side.
The Button and the Safety Switch
The button is the Delta's signature. It is large, it is easy to find by feel, and it works through a winter glove or a work glove without fine motor control, which is the reason the Delta leads our gloved use guide. The safety switch blocks the button, so a knife that rides in a pocket, a vest or a pack cannot fire when something presses on it. Slide it back and the Delta is a one-press knife again. That pair, a button you can find by feel and a switch that makes it safe to carry anywhere on the body, is what the Delta offers that neither an OTF nor a manual folder does.
The Blade
The blade is 3.60 inches of D2 tool steel under a titanium coating, hardened to 60 to 62 HRC and ground to a drop point, the all-round shape that slices, carves and still pierces. D2 holds an edge for a long time and takes it back readily at the 20-degree angle every TEKTO blade leaves with. It is a semi-stainless steel, so the coating does the rust resistance on the flats and the exposed edge wants a wipe-down after a wet day. Our D2 steel guide explains the trade. The serrated option adds a toothed section near the handle for rope, webbing and seatbelts, where a plain edge skates, and the plain edge is the better choice for food, cardboard and anything that needs a clean cut.
The Handle
The handle is 5.20 inches long and 0.54 inches thick, which gives a full four-finger grip and enough mass to steady a 3.60-inch blade. It is contoured where the fingers fall and textured where the palm sits, with jimping for the thumb and forefinger, so the knife stays put when the hand is wet or gloved. The G10 scales, a glass-fiber laminate that does not absorb water or get slick, come in black, desert and OD green. The forged carbon option sets carbon fiber in resin under heat and pressure, which leaves a marbled pattern no two handles share, and our Forged Carbon Edition post covers it. A glass breaker sits on the butt, a lanyard hole takes a wrist loop, the clip is ambidextrous, and the knife comes with a TEKTO pouch.
The Weight
At 5.96 ounces the Delta is the heaviest knife TEKTO makes, and the weight sits in the hand rather than on the clip. For a knife used all day, that mass is what keeps a long cut straight and a hard cut from twisting. For a knife that lives in a dress pocket, it is the reason to look at the A5 Spry or the Delta Mini instead. The blade can be engraved.
Tested and Changed on Feedback
Friends of ours at a local Air Force Reserve unit carried the A3 Delta prototypes, told us what worked and what did not, and we changed the knife on their feedback. The Delta on sale is the one that came out of that loop. It is also the knife our first responders guide recommends for gloves, winter and anyone who opens a knife by feel.
The A3 Delta Mini
The A3 Delta Mini is the same side-opening mechanism, the same button and safety switch, behind a 1.90-inch titanium-coated D2 drop point in a 4.00-inch G10 handle, at 2.54 ounces. It exists for California, where automatics with blades under 2 inches are legal to carry, and for the cities with a 2-inch or 3-inch line, and it is the one to pick when the full-size Delta is more knife than the pocket wants. It comes in black, desert and OD green G10, with a glass breaker and an ambidextrous clip.
Where It Is Legal
A side-opening automatic is a switchblade under every state statute, so the rules are the same as for an OTF. Automatics are legal to own in 45 states and banned in five. Among the 45, a few set blade limits, and at 3.60 inches the Delta clears most of them and not all. California bans carrying any automatic with a blade of 2 inches or more, which rules the full-size Delta out and the Delta Mini in. Our 50-state guide has one line per state and a full page for each, and the California-legal page covers the under-2-inch rule in detail.
Care
Wipe the blade dry after a wet day and keep a film of oil on the edge, which the coating does not cover. Work the action a few times a week if the knife sits, and put a drop of oil at the pivot every few months. The safety switch and the button need nothing beyond keeping lint out of them. Our folding knife maintenance guide covers the routine, and the limited lifetime warranty covers defects in materials and workmanship.
The Delta Beside the Spry
The A5 Spry is the OTF: a 3.50-inch S35VN blade, 3.49 ounces, a slider instead of a button, and a blade that never crosses the hand. The Delta is the side-opener: a 3.60-inch D2 blade, 5.96 ounces, a button and a safety switch, and a lockup with no play. Pick the Spry for a lighter pocket and a stainless blade. Pick the Delta for gloves, for a bigger handle, and for a knife that takes side load. Our OTF buying guide and automatic vs folding guide settle the question before you spend.
The Delta and Its Relatives
The full-size Delta, the Mini for the 2-inch states, the OTF alternative, and the button-lock folder that shares its handle feel.
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OUT OF STOCK
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People Are Asking
What are the A3 Delta's specifications?
A 3.60-inch titanium-coated D2 drop point, plain or serrated, hardened to 60 to 62 HRC, on a side-opening automatic with a button lock and a safety switch. A 5.20-inch handle in black, desert or OD green G10 or forged carbon, 8.90 inches open, 5.96 ounces, with a glass breaker, a lanyard hole, an ambidextrous clip and a TEKTO pouch.
What is the difference between a side-opening automatic and an OTF?
An OTF fires the blade straight out of the front of the handle on a track. A side-opening automatic keeps the blade on a pivot like a folder and a spring swings it open when the button releases it. The side-opener gives a stronger lockup with no blade play and a larger button, and the OTF gives a blade that never crosses the hand and a lighter knife.
Is the A3 Delta good for gloved hands?
It is the TEKTO knife we recommend for gloves. The button is large and easy to find by feel, the handle is 5.20 inches with texture and jimping where the fingers land, and the safety switch keeps the knife closed in a pocket or a vest.
Is the A3 Delta legal where I live?
It is an automatic knife, so the same rules apply as to an OTF. Automatics are legal to own in 45 states and banned in five, and a few states set blade limits. At 3.60 inches the Delta clears most of them. California bans carrying automatics with blades of 2 inches or more, so the full-size Delta cannot be carried there and the 1.90-inch Delta Mini can. Check the 50-state guide.
What is the A3 Delta Mini?
The same side-opening mechanism, button and safety switch behind a 1.90-inch D2 drop point in a 4.00-inch G10 handle at 2.54 ounces. It exists for California and for cities with a 2-inch or 3-inch line, and for anyone who wants the Delta smaller.
