Warped it BAD! Help! Quick!

ddavelarsen

ddavelarsen

Joined
Dec 7, 2000
Messages
5,179
The blade is in the temper oven for the first cycle, when should I try to straighten it? Should I have done so when I first noticed it between quenches? Before I started tempering? After it's cooled?

Please let me know, as this knife is important to me - it's for Me! And it's special in many ways.

When should I straighten it?

Thanks,
Dave
 
I tried straightening a blade after ht and temper. It was a small letter opener with integral bolster. I though I could fix it, so I put it in the vise and tried to bend it back. Well it snapped in two. Kinda pissed me off because I think I knew better.

I would normalize the blade and straighten it and then redo the HT.

Better safe than sorry.
 
Dave,
I usually have better luck right after hardening, If I break it then it stops me from thinking I'll be able to fix it durring a tempering cycle. May be just as well to stop and start all over again after you get it straight. Actually when you break the blade this is where Custom really starts comming into play......Ray

Saw a vidio Moran did where he took water and poured it on a blade to straighten between cycles, I've tried it with no luck.
 
Dave,
What's done is done. You now have two choices:

1, Go back & do it again, not my favourite choice.

2, Try to straighten at tempering heat with a vice & three dowels.
 
Okay, well I tried Colin's #2, and with the amount of bend I was willing to give it I got nowhere. So I guess I'm back to square one.

Dang! This only adds to my crisis of confidence recently. I carefully normalized three cycles before heat treating, noticed the warp in the second quench. Didn't check in the first quench.

This is a damascus blade, I think the steels would be industrial band saw blades and milder steel. (Reg, if you see this and remember what it is, please let me know. This is my No. 1 repro, so you know it's important I get it right!)

So what now? Normalize, try to straighten in the vise with three rods. Should I do this at heat? Or wait until it's cooled to hand temp? In between those temps?

Then what during HT cycles? If I see it warp in the oil again should I immediately try to straighten? Check for straightness before the quench?

Any ideas always welcomed!
 
If you normalize, it should be able to be straightened at any temp. the important thing is to normalise again after straightening, otherwise the stresses due to the straightening may re-occur during ht.

I'm led to believe that you can straighten immediately efter quench, but have never been brave enough to try:eek:

I'vebeen able to straighten warped lades at the tempering stage with some success (not had one break on me yet & have seen some real big arcs :D )
 
Dave,
If you edge quenched the blade, after tempering cycles you should be able to straighten the blade in a vice with 3 dowel rods like colin stated. I have straightened several blades in a vise after tempering using the dowel rods, its a little unnerving some times, because the blade will have to be extremely bent in the vise to remove a slight warp. But the way I see it is, if the blade won't take the extreme bending to straighten, and breaks, then it wasn't right in the first place, and I need to go back and recheck my heat treating techniques.
Another thing is, if you normalized correctly and didn't over heat during the quenching cycles it actually shouldn't have warped, unless its an extremely long blade. Then I would have clay coated the spine and edge quenched up to the clay line. I have done several bowies this way lately, 1 with a 13" blade and they all stayed nice and straight. I know we all have different ways of doing things, I hope this helps.

Good Luck

Bill
 
:( Dave, I'm sorry you are having troubles with the heat treat. I know you are using the mini-forge like I have. When I am normalizing or heat treating I hold the knife in my tongs and keep it moving so that one side doesn't receive more heat than the other. That hot spot may be the problem, I am always on edge with it. Don't despair, you can always re-heat treat it.
 
Dave
I straighten RIGHT after the quench from the heat treating
be it air or oil quenched steel
JUST as soon as you can handle it. don't wait too long though
because it's getting harder ( brittle ) as time goes on
I haven't had one brake yet, but
I haven't had to bend them a lot ether,
the hair will stand up on your neck as your doing it.

I've straightened a 1095 7" blade warped 1/8",


right from the oil,
just to the point of cool to handle, with
3 1/2 halfed dowels split to looks like a D from the end
at about 3" apart for the two on bottom 1 on top at center
and had to bend it all most 1/2" to get it out.
a little at a time on each try..you don't want to over do it.

I won't try this after the >tempering on stainless and
air quenched steels

I have no problem with straightening on differential
hardening steel either after the back is drawn down or
edge quenched and tempered.(drawn down) either way on
this stuff. the ABS test:D
 
Before I learned about even heating and normalizing I used to use a pair of pliers to straighten the blade in the oil. I'd hold the blade with my tongs and if it started to warp while quenching i'd just grab the end with the pliers and bend it back. you have to be fast cause you only have maybe 2 or 3 seconds before it is too hard to move this way.
 
Bill may have the answer; it may be overheating. Remember, that's what started this whole mess! Me worrying so much about overheating that I underheated a couple that didn't harden. And I was having that problem this morning, still underheating testing on a file. I could only make it break when I got it good and hot, past non-magnetic and a brighter color. Did the same with the knife - maybe that's why it warped. Also, I did not like the large grain structure on the file after my heat. So leads me to think of overheating again.

Dan, this is really embarrassing, cause it's about a 7 inch blade with 1/4 spine. This baby just should not warp.

Another thing that occurs to me is the quenchant - may not be bringing it down fast enough. I'm just using vegetable oil at 140 degrees. But it's a small pan, the temp goes up to 160 during the quench.

Guy, I was careful to keep the blade moving, heating the spine and reaching an even heat throughout all at the same time - pretty much anyway. Like you said, in that forge there's really no way to lay the blade down without creating a real hot spot.

I will normalize and straighten the blade, try not to overheat again. Dan and Bill, thanks for the encouragement on bending, cause I know I wasn't giving it enough bend as you described. It's just this is a special piece of steel in a special knife, don't want to break it! That would be like breaking an irreplaceable heirloom or something.
 
Dave,
I was having a few more blades warping on me at one time. Mentioned it to Wayne Goddard and he said I need something slower. Didn't have the fixens for Goddard's goop but went to Crisco and my warping percent has gone down to about 2%. It sure smells alot better also. The darn mice sure like it, little buggers.
 
Dave, I triple quench and before the last quench I check the blade to see that it is straight if not I straighten it by laying it on the anvil and tapping with a hammer then equalize the heat and quench. I also heat treat right after forging and normalizing and have never had a warped blade that was made with new steel. I had a sword that has a good case of memory and no mater what I do it won't straighten out.
Gib
 
Dave back up...
are you edge quenching or doing a full submerging quench?
Goddard's goop is for edge quenching..
I'm using olive oil for my full submerging quench at 130 deg.
 
Dave,

According to my limited but studied experience, it makes little difference when you straighten the blade using heat (I presume we are not talking about a warped tang). However, it must be re-treated from start upon straightening. If only the tang needs straightening no re-HT is required but a temper or two may be desired depending on wether you help cool the tang or not.

Roger
 
Dave sorry your having so much trouble with this blade. I have not had any warp just one delaminate on the cutting edge. Lloyd has had a few warp. If it happend to a 20 year guild member it can happen to anyone. Your billet was what we call TOH and mild steel. TOOL STEEL OIL HARDENING.

The ones LLoyd had warp some we heated and tapped straight while hot some we heated and put in a bucket of builders lime to aneal it then used the pins.

The bottom line of your post says it all. If you get it right the first time.

The other thing is that was one of the first billets I did on the roller I was still learning at that time may be its the steel.

Or I normally heat the whole blade not the edge. I use a deep tin of oil Cooking. I keep the blade vertical and in one smooth movement I lower the blade point first. about 1 second to slide the whole blade in.

Sometimes the catches fire so have long tongs. After a couple of seconds in the oil I slice the bladeback and forward not side to side.

If annealing does not work. I will make you a new billet.
 
Reg,

Thanks for explaining TOH to me. I was going to email back to you for what that ment. Should I HT the TOH damascus at about 1450 - 1475F. (about like I would O1 steel)?? Please advise. I can't use it for this current knife's bolster because I have decided on a Loveless design and there will not be enough thickness. However I have coming next a D'Holder patterned Bird and Trout that I may use it as both blade and bolster.

Your bucks will be in the mail this Monday. I have been on the road this week during the day and have fallen behind on my snail mailings.

Roger
 
Roger
I am a bit of an amature when it comes to heat treating. The technical stuff re multi quench and temperatures is a bit out of my capacity.

I was taught by watching a local blade smith. I see a colour then quench it. I actually did my last heat treat a few days ago. I tried the magnet on the blade that I saw on the forum that worked well.

I had lost the colour on the previous knife. I had got the blade too
hot and ended up with spots. I was using a welding heat forge not a forging heat forge. I have decided to do heat treating in a warming forge now not a full welding heat. It seems safer for me.

It may not be scientific but I use a good file to test the edge of the blade for hardness.
 
Well, on the third normalizing cycle I put it in the vise between my hanging rods and gave it a good bend. Eureka!

It came out nice and straight again. The steel still had some color in it when I bent it back, as I was hoping to fix that shape while it was still in the normalizing cycle.

It had lost all its color by the time I got back out to the garage, so I went directly to the hardening heat. Brought it up carefully and as slowly as possible in my forge (which may not be as slow as I'd like, can't wait until I get my salt pot built).

Interestingly Guy, I may have caused this warp the way you suggested after all. My burner comes in at a bit of an angle and I was moving the blade through the flame spine first, intending to get as even a heat as possible. But this morning I noticed that the angle of the blade was not perfectly parallel with the flame and the side most exposed to it was the side toward which the warp bent. So I think you were right.

I'm about to go see if it hardened. Wish me luck!

Thanks for all the help, gents.

Dave
 
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