Guiltyspark Posted September 30, 2012 Share Posted September 30, 2012 I am having major trouble straightening. Blades. I think my blades slowly warp after I check for straightness after correcting a flaw. When doing full tang blades it seems like this is an impossible task to level the tang out. I don't know if I haveremoved too much material or if I am bending it too far or not enough. Please list all the techniques you use to straighten your blades as I am lost to the process Quote Link to comment Share on other sites More sharing options...
WmHorus Posted September 30, 2012 Share Posted September 30, 2012 I rarely if ever have a tang warping on me since I dont heat the tang or quench it, I keep it out of the oil when quenching. Ive had some warps on thinner blades but i usually correct that shortly after pulling it out of the tempering oven. I have a block of wood with 2 shaped handles on the ends and a slit in the block to put the knife for corrective tweaks. Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted September 30, 2012 Share Posted September 30, 2012 You really did not say at wot point in the process they "slowly warp" lol. But let me offer a few thouights. When I started I had blades end up crooked after heat treat.. I found lby trial and error a couple of things that caused this and work to avoid them ever since. The first thing is to make sure the blade is straight when youi are finished with shaping it. Train hyour eye by using a straight edge to check. and if youi do a distal taper yout will have to use some judgement , Lay the blade on a ;piece of flat steel and then flip it over and look all down the length of the blade to see how it compares side to side. If you taper the blade and the full tang it will require more looks to see how straight it is. When you forge a blade by forging youi create stresses insdie the steel. In the quench the blade can move and come out hard but bent. Normalizing relieves the stresses. i had a problem loong back and it boiled down to how I put the blade into the quenchant. i cought myself putting the hot Blade in more on one side. And the blade would arch toward that side. So now I leave all blades a little thicker for clean up after hardening. If I find a warp the is more than will clean up, I heat to non magnetic and straighten, then repeat normalizing and hardening,,,, Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted September 30, 2012 Share Posted September 30, 2012 You really did not say at wot point in the process they "slowly warp" lol. But let me offer a few thouights. When I started I had blades end up crooked after heat treat.. I found lby trial and error a couple of things that caused this and work to avoid them ever since. The first thing is to make sure the blade is straight when youi are finished with shaping it. Train hyour eye by using a straight edge to check. and if youi do a distal taper yout will have to use some judgement , Lay the blade on a ;piece of flat steel and then flip it over and look all down the length of the blade to see how it compares side to side. If you taper the blade and the full tang it will require more looks to see how straight it is. When you forge a blade by forging youi create stresses insdie the steel. In the quench the blade can move and come out hard but bent. Normalizing relieves the stresses. i had a problem loong back and it boiled down to how I put the blade into the quenchant. i cought myself putting the hot Blade in more on one side. And the blade would arch toward that side. So now I leave all blades a little thicker for clean up after hardening. If I find a warp the is more than will clean up, I heat to non magnetic and straighten, then repeat normalizing and hardening,,,, Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 1, 2012 Share Posted October 1, 2012 yup we need a description or *your* process and where the warping is happening. For me if the warp happens in the hardening process I will immediately reheat, straighten, normalize (if it's an alloy that profits from normalization) and then re-harden. Hardening a blade with the edge too thin also increases the likelihood of it warping. Heating the blade too much in the final clean up grinding can cause warps,... *Details*! Quote Link to comment Share on other sites More sharing options...
Corin Posted October 1, 2012 Share Posted October 1, 2012 As said above lots of things cause a warp, but there are some good ways to correct them without stress or much risk... Most warps can be corrected by getting a small G clamp and a piece of slightly curved leaf spring. Heat the knife and spring in the oven to tempering temperature, and place the knife against the concave side of the piece of spring. apply a small (1") G clamp to the blade and spring at the place where it warped and tighten till the blade is straight (where gloves as everything will be hot obviously) temper for 1-2 hours, cool, check and if not straight, do it again this time going a little past the straight point when you clamp, and see if that works. Every blade i have corrected with this method has come out perfect. If this is not clear enough and you need a picture just let me know. Quote Link to comment Share on other sites More sharing options...
2Tim215 Posted October 2, 2012 Share Posted October 2, 2012 If your blades are warping after HT and they are cold they can warp because of surface tension. It sounds like that from what you said in your post ie - "correcting a flaw". I assume by this that they warp sometime during the grinding process. If this is so what you are doing is allowing certain sections of the blade to get too hot whilst grinding and this creates surface tension and warps the blade towards the cooler side. It's very important never to allow a blade to get too hot when grinding. If this is not the case the best way to keep blades straght is to clamp them between two 20mm mild steel plates and then place into the still hot but not running (burning) forge overnight to slowly cool. This will anneal the metal properly so that you do not have uneven structure within the steel then when you do the HT you can use the same method with the plates to keep the blade straight after quenching - you have at least 5 minuts to do this after quenching as the steel is still reasonably malleble. I have often in the past placed a quenched blade onto a cold surface only to find it warped later - this is because the still warm blade now cools faster on the side placed on the cold surface thus creating surface tension and warping - hope this all helps. Quote Link to comment Share on other sites More sharing options...
Robert Yates Posted October 2, 2012 Share Posted October 2, 2012 warping is happening, is a lot due to one side of the blade having more material on it than the other . while it does take time and a bit of precision to eliminate it one can correct it by heat . Sam Quote Link to comment Share on other sites More sharing options...
Taylor Made Posted November 25, 2012 Share Posted November 25, 2012 Another way to straighten a warped blade is to heat the warped area while in a vise, say using a propane torch. Place 3 bolts in the vise, using 1 bolt to push in between the other 2 on the other side. You are using the 1 bolt to push in between the other 2 bolts. Crank down your vise to a little past straight and see if you got it when you back it off. Just one way of doing it. I have used this method with good success. You are going to want to protect your blade from the threads of the bolt. Some slick rod say 3/8 works a lot better. Quote Link to comment Share on other sites More sharing options...
gearhartironwerks Posted November 25, 2012 Share Posted November 25, 2012 Thermal cycling and annealing prior to heat treating have helped me a lot. The 3 point method in the vise after tempering also works well. It sure is frustrating to see a warped blade coming out of the quench. I can relate. John Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted December 6, 2012 Share Posted December 6, 2012 http://www.iforgeiron.com/topic/9135-warpingstraightning/ covers it Quote Link to comment Share on other sites More sharing options...
Stormcrow Posted December 6, 2012 Share Posted December 6, 2012 After forging, triple normalize and it will take care of stresses in the blade, which cause warping. If you have quenched the blade and it's warped slightly, with plain carbon steels you do have about thirty seconds after the quench to flex it straight again. I've never tried it with a water quench since I always oil quench. Be careful as you can snap the blade doing this if you let it get too cold or try to flex it too much. A safer way is pretty much what Corin said. Do your first tempering cycle, then before the second one, lay a stout flat piece of steel along the warp with a spacer at either end between it and the blade. I usually use a big worn out file and a couple of washers. Then C-clamp the blade and flex it a bit past center and run the whole mess through another tempering cycle. Then take the C-clamp off, check for straightness, and do it again if need be. If it's straight, go ahead and do your third tempering cycle. Doing it with two spacers lets you adjust the distance depending on how big the warp is. Quote Link to comment Share on other sites More sharing options...
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