Help my edge is chipping.

R

Ryan J

Joined
Jul 14, 2014
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233
Hey everyone. I Googled around but couldn't find an answer for this.
So I made my first liner lock. It's turned out beautiful. Centered blade, centered lock up, works like a pocket watch. This was made all the more difficult because I used stuff lying around the shop so that I wouldn't waste money ruining materials while learning. I made the blade from a file. Now, as a disclaimer, I will not do anything I'm not confident about on a knife I intend to give away, let alone sell. That being said, I did the heat treat. I've done a few files with good results. This time I made a charcoal Forge with a blower. Heated to austenite, quenched immediately in oil, and tempered at 425 for an hour, twice, quenching in water between tempers.
I botched it somehow. Spent forever finishing this knife. The last thing I do is put the edge on, for safety. So I go to do that and it's chipping out along the front half. Initially I put the edge on with the belt grinder moving very slowly and not letting any heat build up. Then use the kme sharpener. Started out at about 18 degrees, noticed the chipping and increased the angle. Even at 26 degrees, same problem.
Sorry to write so much. Is there any fix for this? Can I temper it back further to soften it?I made it for myself so there's no concern with a customer or such. Although I hope it isn't true I think I just learned a hard lesson. The problem is solved with knives I make others by eliminating mystery steel and sending off for heat treat. But I haven't made one for myself yet and this is that. Sure would like to salvage it.
 
Bumping the temper up is a good place to start. Try 450. If you're still chipping at that point, your issue might be overheating. If you overheated the edge before the quench (really common and really easy to do), you'll end up chippy.
 
Thanks for the reply. Over heating was my suspicion. Mainly because it's the front half which is smaller so would heat easier. It's a wharncliffe. Just tried grinding back to fresh metal. No chipping off the grinder so we'll see. If there is still chipping ill try retempering.
 
Yugami said:
Extremely large brittle grains form.
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I see. I thought something was wrong because it seemed way to easy to polish. Got in the oven now to re temper. I asked about de carb because I wonder if it can be re heat treated.
 
I highly recommend hardening and tempering your folder blades before grinding. They are too small after grinding to control the heat, especially in a forge. I also think your one-hour draws are an hour too short. I would increase the time before bumping up the temperature.

Bob
 
RangerBobTX said:
I highly recommend hardening and tempering your folder blades before grinding. They are too small after grinding to control the heat, especially in a forge. I also think your one-hour draws are an hour too short. I would increase the time before bumping up the temperature.

Bob
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Interesting. So does this go for having them professionally heat treated as well?
 
If it is chipping while you sharpen, you definitely overheated the steel. You may find some non-chippy stuff in there, somewhere ... but it simply means you've gone back to "overheated" steel rather than "severely overheated".
 
Well damn. I guess I'll chock this one up to a lesson learned. I'mfeel fortunate however that it worked so well. Can't really call it the first go around because I made two blades and probably 3 sets of liners before I was happy with it. Can't win em all I guess. I'll be sending everything out for heat treating for sure until I can get a proper oven
 
Ryan J said:
Interesting. So does this go for having them professionally heat treated as well?
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I think all folder blades should be ground after HT regardless of who does it. I do however, put an initial bevel on W2 folder blades to aid in creating a hamon.

I would also say that water quenching after your temper is not a good idea, just let it cool in still air.

Bob
 
Well it's fubar. Retempered at 450. Way past normal. It had blues and reds. Looked neat though. The chipping was less visible as I sharpened to higher grits. At 13k grit nothing was visible to the naked eye so I was hopeful. Cutting paper however revealed the chips were all there. Hung up completely when push cutting. For shame, it was a pretty bastard.
[img=http://s22.postimg.org/fvhvvgz7x/IMAG0973.jpg]


http://postimg.org/image/cqkxvdeox/ sorry guys guess you gotta click the links. Can't get thumbnails to work right
 
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RangerBobTX said:
I would also say that water quenching after your temper is not a good idea, just let it cool in still air.
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Water quenching after tempering is perfectly fine. In fact, it actually benefits the steel(increasing resistance to cold embrittlement) to a very small extent. Negligible, but it is there. At the very least it saves time. Slow cooling does nothing but make you wait for no good reason.
 
Rick Marchand said:
Water quenching after tempering is perfectly fine. In fact, it actually benefits the steel(increasing resistance to cold embrittlement) to a very small extent. Negligible, but it is there. At the very least it saves time. Slow cooling does nothing but make you wait for no good reason.
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Yeah I'd done my research on that. Stacy said it was beneficial and I take his word for it.
 
Bob, a water quench between tempers is suggested on many steels to reduce the formation of some unwanted precipitates, and can be done with almost any knife steel with no adverse effects. It also has the added benefit of letting you get right to your next tempering cycle.

Also, some steels only require one hour temper cycles. Simple steels such as W2 and 1095, in the cross sections we use them in, are more than fine with one hour temper cycles.




RangerBobTX said:
I think all folder blades should be ground after HT regardless of who does it. I do however, put an initial bevel on W2 folder blades to aid in creating a hamon.

I would also say that water quenching after your temper is not a good idea, just let it cool in still air.

Bob
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Ryan J said:
Yeah I'd done my research on that. Stacy said it was beneficial and I take his word for it.
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Stacy will be the first to tell you to NOT take anyone's word for it. That said, it can be hard/confusing at first. Wrapping your head around the metallurgical aspect of knifemaking is a slow endeavor. Finding a source you "trust" is touch and go until your knowledge base grows. Ask questions and learn the reasons why folks do what they do. Rule of thumb ... if someone tells you they have found a way get vastly superior results that defy modern metallurgy ... duck and run, buddy.
 
I do all my folder blades after heat treat. Sure care and discipline in the manner of doing it is necessary but a lot of knife making is like that. Just another thing you can learn.
Frank.
 
Frank Niro said:
I do all my folder blades after heat treat. Sure care and discipline in the manner of doing it is necessary but a lot of knife making is like that. Just another thing you can learn.
Frank.
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So you don't do any bevel grinding before heat treat? No matter the steel?
 
Salolan said:
Not on folders. Most will even do all the blade fitting and tang adjustments on a folder prior to grinding in the bevels.

Chris
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That's good to know. I did all the fitting first to make sure it worked before I ground the bevels and put time into finishing, but I heat treated it last. I wonder then if this applies to all small knives? A lot of neckers and such have blades around the same size as folders . I was under the impression that as long as you left the edge thickness to the recommended measurement for the steel that was all there was to be concerned about.
 
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