Tip of Knife Chipped Off

[milton yang]

My wife dropped our Hattori FH Gyuto this past weekend which resulted in the tip being chipped off.  Should I worry about bits of metal ending up in our food accidentally if I keep using it? Are there any repair options or should I be shopping for a new chef's knife at this point?

 

[gunnar]

if you have a set of stones you can rework the tip and be fine.  If you don't have a set of stones a smooth file will at least let you take the burrs off the tip.

 

[boar_d_laze]

It depends how much tip you lost. 

Tips are actually fairly easy to grind -- you should nearly always work from the spine (top) of the knife and leave the edge alone.  Just blend the top into the edge at whatever angle you like.  You don't need to keep a curve or to match the manufacturer's angles.

Obviously, it's easier to do with an electric grinder than a stone.  Naturally I always work with stones.  After you've ground a new tip, don't forget to polish it as much as you're able.  Sandpaper is probably best if you're using hand tools, and buffing wheels if you're using a power grinder. 

If you've lost a lot of tip, you'll definitely want to hunt down someone with a grinder -- ideally, someone who is also competent to make the repair for you.  If you've only lost a little, you can easily handle it yourself.

Files fall somewhere in between stones and grinders.  Just incorporate the advice for stones.

One thing though -- if you're using a stone or file, stroke from front to back (and vice versa) along the knife and not from left to right across it.  Obviously, that doesn't apply to sand paper -- that you'll want to "shoeshine" across the knife.  Not only will it take the rough off, It will "crown" the edges of the spine -- a good thing in itself.

Hope this helps,

BDL

 

[trooper]

Broken tips are a fact of life but easy to fix. I just grind gently from the spine-side, back a few inches from the tip - and taper it in, as naturally-blended as possible.

As BDL says (Who I have elected as my go-to knife expert) - Broken tips make you frown more than they are a real issue to deal with.

This is an FHK Suji that I use for meat - It tried to sky-dive into a concrete floor... I don't know why... But I was just happy my foot got out of the way.

The patina on that slicer is au natural by the way... just blood oxidization.

 

[milton yang]

Not much tip was lost. It's probably just a little more than Trooper's suji and less angular. Thanks for all the suggestions.

I'm still having a little trouble visualizing the end result. Am I looking to just smooth out the "nub" or actually make a new point?

 

[trooper]

Not much tip was lost. It's probably just a little more than Trooper's suji and less angular. Thanks for all the suggestions.

I'm still having a little trouble visualizing the end result. Am I looking to just smooth out the "nub" or actually make a new point?

Always try to go for a new point if you can. The objective is to blend and taper the spine into a graceful point - so it doesn't look like a sheep's foot.

I made kind of a cheesy example of what you should go for, and what you should NOT do.

 

[brianshaw]

I know this isn't the recommended way, but I recently fixed a broken tip on a carbon steel carving knife.  I modified Trooper's picure to illustrate what I did.  I did it backward... from the edge side since I was having difficult time visualizing doing it from spine side.  First I ground a chunk out of the edge along the line.  I used a coarse stone and elbow grease to grind the chunk out.  Then sharpened on stones and reworked the curve.  It worked, but there is likely a very good reason why few recommend reshaping from the edge side.

 

[phaedrus]

The main reason you work from the spine down is so you don't lose any more cutting edge than necessary and don't change the edge profile.  I've fixed knives with over 2/3" of the tip broken off and I would recommend lowering the spine to meet the edge, not the other way around.  That said, your regrind looks good, Brian.  To the OP:  If the area affected is small you can reshape the tip on the same stones you use to sharpen it.  A slightly larger area of missing steel probably calls for something akin to a DMT XXC.  Badly broken tips are best left to powered gear (generally a belt grinder).  Technically it's possible to fix a badly broken tip completely by hand but it would take a veritable eternity to do on stones.

Here's a quick example of one I fixed that had about 1/3" of tip broken.  I used a belt sander, starting with an 80 grit Cubic Zirconia belt and working my up to a 9 micron 3M belt.  The knife is a Hattori HD santoku (and sorry for the crappy pics):

Before:



After grinding:

 

[chrisbelgium]

I had to restore a broken off tip from a Hiromoto AS santoku. I simply took a part off like Phaedrus suggest, with a belt sander that I turned on it's back and laid it flat on the ground, so I had my 2 hands free to manipulate the knife instead of manipulating a heavy belt sander. Extremely important; just make sure the belt turns away from your body!!! And do take enough metal away, just like in Trooper's pictures. Takes very little time, even a tough one like the Hiromoto. You'll have to stop a few times as the blade will heat up too much.

An expensive Hattori FH is well worth to restore properly. It's really no big deal at all with a cheap belt sander like mine.

 

[phaedrus]

Also remember that it's the finer belts that generate heat as a rule, not the coarse ones.  Most of the time if you burn a blade it's on a fine belt.  Probably it's because you're removing so little metal that you're tempted to keep the blade in contact with the belt longer than you should.  But not matter the belt, use a relatively light touch and keep the contact with the belt brief.  I keep a pitcher of water nearby to dunk the blade to cool it.  You do have to make sure the knife is dried off, though.  Some brands of belts will melt if you get them wet.  IIRC, Doug Rising mentioned that Trizact belts should be gotten wet.  I've got belts down to 40 grit, and those make short work of most jobs.  I do plan to get a 42" grinder, though.  The one I'm looking at runs about 1/2 the speed of my little HF, so combined with more surface are it should run a lot cooler.

 

[chrisbelgium]

Indeed, we humans usually say that others drop a knife, while we say "it fell" as we refer to our own debacle. lol
 

My wife dropped our Hattori FH Gyuto...