In a pinch probably OK. But I had a coworker who used to use his car key for boxes in the office. That is until it no longer worked in his car due to wear. Keys are soft brass. They wear really fast when they encounter paper or cardboard. I use a P38 that I have carried since 1970. I think I might have replaced it once. It serves many uses but is ideal for none other than opening cans.How many boxes you opening with it?
In a pinch I've always just used an actual key. Looks like there are plenty of "sharp" keys or key like objects out there capable or breaking tape but not actually sharp enough to hurt anyone
Yeah I certainly wouldn't do it every day.In a pinch probably OK. But I had a coworker who used to use his car key for boxes in the office. That is until it no longer worked in his car due to wear. Keys are soft brass. They wear really fast when they encounter paper or cardboard. I use a P38 that I have carried since 1970. I think I might have replaced it once. It serves many uses but is ideal for none other than opening cans.
Is the Gerber Prybid too big for your needs?
I think size is the limiting factor for both of these, really need something small as its going on a keychain.Give the Canary box opener a look.
Most are traditionaly brass (or nickel plated brass) but some are steel, stainless steel, or titanium.Keys are soft brass. They wear really fast when they encounter paper or cardboard.
For me it varies.I just carry a pocket knife....
I never “sometimes” carry a knife. It’s as much a daily thing as pants and shoes. The only variance is which one I have that day.For me it varies.
Sometimes I carry my old Buck 112. But on my keychain, which is always in my pocket, is a Leatherman Micra. The little blade works OK for ripping tape and even cutting corrugated cardboard in a pinch. I don’t think a toddler could very easily get his/her fingernail into the slot and get the blade open.
I despise carrying keys and normally don’t.

I get you.I never “sometimes” carry a knife.
My front door has a keypad, and my wife works from home. My truck has a keypad and I leave the key in the ignition and lock the door. If I drive one of my older trucks, the key ring has at most two keys on it.How do you leave your house? Even if I ride my bicycle, I still have a key for the lock.
Teach me how to master this dark art![]()
I get you.
If you count a Leatherman Micra as a knife, then I too always carry a knife. If I’m doing outdoor activities expecting to have to cut things somewhere I’m going, I will add my Buck 112 to my pocket.
If it works for you, great. I would feel like I didn’t have a knife if all I had was a Micra.
Something like a Spyderco Endura, Case Kinzua or Longhouse are the usual.
ThanksIf it works for you, great. I would feel like I didn’t have a knife if all I had was a Micra.
I use those other functions of mine are just as important. The bottle opener is quite handy and makes a statement about self sufficiency when you open a cool one somebody hands you.I have a micra on my keys, but not for the blade. The scissors, screwdriver, tweezers etc all come in handy. I don't think I would trade for just a box cutter.
The real question is... why am I on Garage Journal while at the beach?
I don’t know how many I’ve lost or had confiscated by the TSA, but I like keeping one of these on my keychain. No bigger than a key but several more functions than just a blade. It doesn’t lock, but I think a toddler would have a hard time opening it. Takes a sturdy thumbnail to get it open.
6-IN-1 UTILITY KEY-SWISS+TECH
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I think size is the limiting factor for both of these, really need something small as its going on a keychain.






My EDC up til COVID, when I didn't leave the house. I've never used it on a keyring tho.would be the Gerber Ultralight LST:
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Victorinox SD guy here. I realized like 30 years ago that I had never needed to skin an elk that wandered into the shop, or fight off ravening zombies, or cut a burning tire off a magnesium minilite wheel.. As a mechanic, I mostly opened the boxes that parts came in. And the toothpick, tweezers and nail-file were useful. I used the scissors maybe every 5 years.There is stuff like the Olfa TK-4 (has a keychain hole but no lock):
Or Slice Mini (has a slide "lock" on the heel and you could drill a keychain hole):
But I wouldn't really trust a sliding mechanism like that in a pocket. They also have larger surface areas, which is good for grip, but maybe a bit large for a keychain.
How often do you really have to open packages with a keychain tool when something better isn't within reach? Most of my package opening happens at home or at work where I have dedicated box cutters available, but YMMV.
Cutting tape on boxes is messy and any non-disposable knife, particularly a folder, is likely to get gummed up over time and require cleaning. But a dedicated knife can be useful for a lot of other stuff as well.
The Victorinox SD is a solid multi-use option if it has to be on a keychain. Scissors and tweezers are nice to have day to day, and while the blade is small, it can work on stuff like tape or food in a pinch. Mine is from my mom, it's at least 30 years old and I have carried it in my pocket for about 10 of those. Length is just slightly longer than a house key, they are cheap, and come in dozens of colors.
I also carry a Boker Titan II in my purse, which is still very slim but has a slightly more substantial blade for cutting food like fruit or cheese when I am out.
A similar option would be the Gerber Ultralight LST:
Or Otter Mercator:
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I have no keys for my house. The doors are all keypads without even a key slot.How do you leave your house? Even if I ride my bicycle, I still have a key for the lock.
Teach me how to master this dark art![]()
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Yeah, that's what my dad had for apples when we were little.My EDC up til COVID, when I didn't leave the house. I've never used it on a keyring tho.
I like the materials and craftsmanship on that but I suspect it would have the same issue as OP's current knife (lock knob coming loose).![]()
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Here are a couple of key ring appropriate cutters I posted on the tiny tool thread some time back.

I carried a Christy through high school and college until I was drafted. I think back then they were a dollar. Thought nothing of it when I threw it into the can for basic training. Now I see they are $44. Nice little knife but that is ridiculous.The Christy pocket knife is a compact, well-made locking/sliding blade made by a small company in northwestern Ohio for decades.
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Looks like it might fit the bill.
The knock-off arrived from Aliexpress and i've been using it daily for a while now. Happy to report it works awesome and is exactly what I needed - no way a toddler could open it and its ultra small and convenient.Looks like it might fit the bill.
Quark looks to have gone out of business; or atleast sold out without an ETA, so lets hope the aliexpress knock off is just as good.
I was going to say the same thing. If you don't want to carry a knife with you, the Gerber Shard on your keychain works great for a bunch of uses including opening boxes.