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anything to do with a warped blade?

Sun May 05, 2013 7:59 am

I have a 50+ year-old 12" Ontario Knife Co carbon chef's knife that I pull out for heavy jobs when I don't want to put my UX10 at risk. The entire blade warps to the right, so much so that when placed on its side with handle flat, the tip nearly hits the counter. I believe it is a manufacturing defect (its marked as a government-issue knife) and I've never really worried about it, but I've often wondered if there is any way to straighten it. Any ideas?

Re: anything to do with a warped blade?

Sun May 05, 2013 8:06 am

I have the same question because I have a 10" SS Henkel slicer I picked up years ago, at a discount, due to warpage. Good knife (aside from the warp) ... just wish it were 2-4 inches longer. The warp starts about mid-blade, and reaches 1/8" by the tip ... too wide to just grind away. In my case, it's probably covered under warranty.

Re: anything to do with a warped blade?

Sun May 05, 2013 8:41 am

http://www.youtube.com/watch?feature=pl ... v6zMGpMPg#!

Re: anything to do with a warped blade?

Sun May 05, 2013 8:52 am

I'm guessing that may help funkspieler, but that it may not work as well for a modern SS slicer, designed to have some flex & shape memory.

Re: anything to do with a warped blade?

Sun May 05, 2013 9:41 am

This can get complicated due to the type of "warp" (i.e., bend, twist, multiples thereof, compound multiples thereof). Mark's method will work on a flexible knife, but you need be more careful as if you go past a point it can snap as opposed to bend. I wouldn't use my hand in that application; rather a wood block to secure the blade face, and I'd be even more tedious in my bend as the stiff wood will create a sharp definitive apex whereas your hand will allow a gentle radius at the apex.

You can also hammer it straight on an anvil or other hard surface. Really depends on the "warp."

Re: anything to do with a warped blade?

Sun May 05, 2013 10:19 am

Thanks for the advice. I think this technique might work with this knife, although I will definitely use something to protect my hand in case of a snap. Will let you all know how it works out!

Re: anything to do with a warped blade?

Sun May 05, 2013 10:24 am

That comment was directed to ISIS for a flexible blade. In your application I would use the heel of my hand as directed in the video...

Re: anything to do with a warped blade?

Sun May 05, 2013 11:58 am

As to the old, Ontario Knife Works blade

1(a). Fix it:
Sandwich the blade between two 2x4s, each of which extends from the handle to slightly beyond the tip. Using "C" clamps, clamp the sandwich in several places, including just after the handle, just before the tip, at the place of the warp, and on each side of the warp. Leave it alone for a long time. After a couple of weeks, it will be as straight as it's ever going to get if you don't use heat (which you can't because it would ruin the temper). Put the knife away, take it out now and then to admire it, but don't use it.

While it was bent, the blade developed "spring memory" and will return to its warped state pretty much no matter what you do. Furthermore, the blade's movement -- whether from warping, straightening, re-warping, re-straightening -- fatigued and weakened the metal.

1(b). Toss it:
If the knife doesn't have sentimental value to you, get rid of it. Unless great grandma used it in the Ardennes to save the 101st Airborne or something similar, the knife isn't worth the trouble.

2. In either case:
Buy a new Ontario Knife Works "Old Hickory." There's no reason not to. They're incredibly cheap and the production problems they suffered during from the mid seventies to the early nineties, resulting in inconsistent blade thickness, tempering, etc., have been fixed. Same 1095 alloy, same thick-rigidity, same horizontal tool marks, same crude handle, allatime same same.


Re: anything to do with a warped blade?

Mon May 06, 2013 11:23 pm

Just out of curiosity, I sent a discreet inquiry to Henkel ...


    Some years ago I purchased a 10" slicer (along with several other knives), but didn't notice right away that the blade had a 1/8th inch warp. At the time, because I'd used and resharpened it, I assumed I couldnt return it.

    Here it is years later, and upon visting your website while knife shopping, I see that the knife has a lifetime warranty against manufacturing defects, and I was wondering if this knife is eligable for replacement.

    Specifics (taken from the blade etching):
    * Style: Henkel Professional "S"
    * Model: 31020-260 (10") No Stain

    Defect: 1/8th inch lateral warp to the left, starting mid-blade and peaking at tip.

    I can take and attach photos, if needed.

    Thank you in advance for a reply.

Their reply:

    Thank you for your recent e-mail inquiry concerning Zwilling J.A. Henckels products. You will be pleased to know that all of our products are fully guaranteed against manufacturer’s defects in materials and / or craftsmanship. The warranty does not cover wear from normal use, or any damage resulting from use other than the intended purpose of the item.

    We will evaluate your product and should it be under warranty, we will gladly replace the product at no charge. We cannot guarantee that the same line or size will be available therefore; it will be replaced under our discretion, with a comparable item or an upgrade. Since your observation is a rather rare occurrence, we would appreciate the opportunity to inspect your item.

    If you are located in the USA, Please be kind enough to address the return to:

    Zwilling J.A. Henckels
    171 Saw Mill River Road
    Hawthorne, NY 10532
    Attn: Consumer Relations Department

    Additionally, please include a letter containing your full name, address, phone number, and an E-mail address with a brief description of the issue.

    Should you comply with U.S. Postal Regulations, items must be wrapped to protect their points and edges from cutting through the outer carton in which they are mailed. In the interest of safety, avoid attaching adhesive materials directly to the product.
    ZJAH is not responsible for packages lost in transit.

    *Please accept our apologies for any inconvenience. Allow 4-6 weeks for delivery.

Nice to see a company that stands behind their product.

It'd be tough to be without my slicer for a month+, but if I do opt to send it in, I'll be sure to put a wicked edge on it first, as a proper viking farewell ... and to let their QA inspector know I'm no slouch. 8-)

Re: anything to do with a warped blade?

Tue May 07, 2013 2:46 am

Skip putting that edge on the knife when it is still warped. Then you will need to correct it after it is straightened, generating yet another problem.

Straightening can be as simple as Mark describes or using a straightening stick to straighten it out. (Pics on request).

Or it can get more elaborate. I straightened out a Takeda Cleaver that was warped in both directions by clamping it to a granite reference block using a series of clamps and satay sticks (wooden sticks used to grill chicken strips about 1/8" in diameter) strategically placed to twist it back into shape, leaving it clamped for a couple days at a time for each adjustment. In the end it came out quite nicely but it did require a lot of patience.
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