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MAC knife: Piece broke off during use... What happened? and What to do?

dost Sep 2, 2011 12:38 PM

I have a wonderfu MAC utility knife that I have had and used daily for over 12 years. I have had it professionally sharpened once or maybe twice, but otherwise it keeps it's edge very well and is in what I think to be excellent condition.

I was just cutting a courgette (spaghetti squash) in half to prep for baking when the blade sort of stuck, and I saw that a chunk had come out of the blade- about 1/2" long and 3/16" deep. This chunk is from about 2/3 of the way from the tip to the end of the blade. Anyone have any inkling as to why this happened or if I might be able to do anything about it? Or was I lucky to have it last this long?

FYI- I keep my knives in a wooden block, only handwash and towel-dry, and cut 95% on wood cutting blocks, 5% plastic (smelly items like garlic, onions, fish). I have never used this knife on bones at all.

Any input is appreciated.

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  1. l
    lcool RE: dost Sep 2, 2011 12:40 PM

    there is a lifetime warranty on some MAC knives,worth looking into

    1. BiscuitBoy RE: dost Sep 2, 2011 01:26 PM

      Is the blade now sectioned, like a jackolantern? Can you post a picture? That is bizzare. Sounds like it was bent in a funny way and snapped. I don't see any fix... It would need to be ground down and what remains sure would feel weird

      1. BiscuitBoy RE: dost Sep 2, 2011 01:33 PM

        wait, I read too fast...3/16, not so bad

        5 Replies
        1. re: BiscuitBoy
          petek RE: BiscuitBoy Sep 2, 2011 03:05 PM

          If the lifetime warranty doesn't pan out,get yourself a nice new knife,plenty of excellent options out there.

          1. re: petek
            dost RE: petek Sep 4, 2011 12:32 PM

            Thanks- The knife was a gift, so I think I would be hard-pressed to take advantage of their 25 year warranty. I will almost certainly choose another MAC when I buy a new knife as I find them to be fantastic. I'm making do with others in my block for now, and using the forward half of this broken knife for simple slicing for now.

            1. re: dost
              Coogles RE: dost Sep 6, 2011 11:51 AM

              I don't know what country you're in, but MAC USA has an accidental damage replacement option where they will sell you a replacement knife for 70% off MSRP and you don't even have to send the broken knife to them if they determine from the photo that it can't be repaired. If they think they can repair it the cost is only $11 plus shipping for 6" to 10" blades. It can't hurt to call them to see what they'll do for you.


          2. re: BiscuitBoy
            dost RE: BiscuitBoy Sep 4, 2011 12:54 PM

            Please see pics and let me know what you think. I thought about having it ground down just as a spare or travel knife (travel knife would depend on how it feels after being ground down- thinking of just getting a victorinox for travel from now on...)

            In the close-up photo you can also see there is a small "split" in the metal about 1/8" in front of the chip....

            1. re: dost
              BiscuitBoy RE: dost Sep 6, 2011 11:04 AM

              wow, that's about what I pictured, what a shame. If you have some connection with this blade, by all means, grind it (and probably thin it)...and like you say, it'd be a good backup knife. I'd probably spend the $$$ on a new blade instead, concerned it may harbor more fractures waiting to happen

          3. petek RE: dost Sep 4, 2011 01:16 PM

            ouch! That's a pretty big gouge you got there dost.You may have inadvertently twisted the blade whilst cutting the squash,stressing the blade and causing it to "snap"(maybe the old MACs were thinner or more brittle than the new ones).You'd have to remove a lot of metal to repair it,not worth it in my opinion.Get yourself a new MAC,they're good knives.

            1. Chemicalkinetics RE: dost Sep 4, 2011 02:03 PM

              I agree with Petek. It is more likely due to a twisting motion (side to side motion) and less likely due to up and down impact.

              Sometime ago, cowboy showed a youtube video by Murray Carter. Jump to 5:05 min mark and you can see how a good knife can chip under stress.


              Your knife could have been weakened over years and finally chip for a minor twist, or it received one good (strong) twisting motion and gave away. In your second photo, it is clear that there is another fracture and it also looks like it is due to lateral stress (side to side). Technically you can grind the chip area down, but it will take much work and on top of that you would need to grind away a lot of metal, so I am not sure if it worth all the efforts. You can still keep it as a practice knife for knife sharpening...etc.

              3 Replies
              1. re: Chemicalkinetics
                cowboyardee RE: Chemicalkinetics Sep 4, 2011 08:12 PM

                I also agree - twisting motion is much more likely to have caused this chip than impact.

                But also - the chip is so big, that I suspect the knife must have had a bit of a tempering problem. I've seen some badly abused knives and they don't often get chips that big on that part of the knife (though you can lose a big chunk of the tip a little more easily). Years of use can certainly weaken parts of a knife edge... but that's still one big damn chip.

                I also agree that chip would be a real PITA to grind out by hand. OTOH, if the OP even wanted an excuse to learn to use a belt sander to sharpen and reprofile, this is a pretty good one.

                1. re: Chemicalkinetics
                  dost RE: Chemicalkinetics Sep 17, 2011 09:30 PM

                  Thanks for the link. I watched it, then tried to chip by putting pressure on the blade as he demonstrated, but could not get it to chip again. It just flexed. Maybe I subconsciously weenied-out and didn't apply enough pressure. Anyhoo, it was interesting and informational. My guess is that part of the blade was weakened as I felt the motion I was using was "normal" and I wasn't struggling with it or tweaking at the time. It just suddenly felt like it was stuck in the squash and when I pulled it out a small piece of pulled out with it.

                  thanks for your input. I really appreciate it. I've purchased another Mac for now, and it's just like old times again! :)

                  1. re: dost
                    Chemicalkinetics RE: dost Sep 17, 2011 11:22 PM

                    Yeah, I am guessing that the edge was weakened prior to this incident. I doubt it was a one-time twist which chips the knife. Well, you did use the knife for 12 years, which is not short. Congratulation for the new Mac. Have fun with it.

                2. k
                  katnat RE: dost Sep 4, 2011 08:42 PM

                  I had a Mac 'bird beak' curved blade paring knife. After less than a year, the blade simply detached from the handle. I always hand wash and dry my knives, take very good care of them. The place I bought it from argued with me and grudgingly replaced it. I do love the knife though - shape and sharpness make it ideal for lots of tourné. I still use the replacement regularly, but wonder whether there are quality control issues.

                  1. TeRReT RE: dost Sep 5, 2011 09:30 AM

                    Same thing happened to my friend's mac knife when he was cutting frozen fat, and was definitely a twisting motion. Also happened to his global when he cut through a peach pit but a little bit smaller. If I remember correctly, mac warranty did not cover it, I don't remember why, but I definitely remember him purchasing the same mac over and paying for it. The global he just slowly ground down over time and continued to use it, after a year of normal stoning and honing the chip disappeared. Mac's are not unreasonably expensive, so even if you have to buy it it won't be so bad. Industry supply stores may even take pity and give a bit of a discount, they did for my friend.

                    1 Reply
                    1. re: TeRReT
                      doctorandchef RE: TeRReT Sep 6, 2011 10:26 AM

                      I had a Mac professional 9.5" chefs knife chip almost exactly like yours (but smaller chunk) while I was cutting salt pork with no bones.

                      I called the company and they told me to send it back to them for an exchange. Got a new knife within 2 weeks and have never cut salt pork with it since.

                      I'm guessing with 10 years of use there's some metal fatigue from years of use. As ChemicalKinetics said, the chip likely is due to some subtle twisting motion.

                    2. kaleokahu RE: dost Sep 17, 2011 09:49 PM

                      Hi, dost:

                      I really do sympathize with you here, but I feel I must channel Walter Sobchak from The Big Lebowski:

                      "Do you see what happens, dost, when you cut a spaghetti squash with a knife with no edge support?"

                      We now, like it or not, live in a knife world dominated by high-RC heat treats (read: uniformly brittle), non-convex grinds (read: little edge support), and overall thin primary (if any) bevels. IMO, this hat trick, with just a little unluck, is a cougette recipe for exactly what happened to you and your MAC.

                      I have been poked fun at here before for opining that spaghetti squash pretty much plead for an axe. A make-do would be a cleaver (with a cudgel to drive it, if you want 10 fingers with you in your casket).

                      Don't beat yourself up about this. Take it out on the spine of your cleaver instead.


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