DonutHands Posted July 3, 2018 Share Posted July 3, 2018 Searched the internet, seems like a forum like this would be an ok place to ask. Got a set of headphones with a metal band that has lost its clamping force, stretched out over time. Short of buying a new set of headphone, figured Id ask if there was a way to bring this metal bands spring back with some type of heat treatment. I know there will be no exact answer as no one knows what kind of steel this actually is, but its already taken apart and if I accomplish nothing, it was going in the trash anyways. Thanks for any help you can offer. Link to comment Share on other sites More sharing options...
Buzzkill Posted July 3, 2018 Share Posted July 3, 2018 If it were mine I'd try bending it around something with a bit smaller diameter than my desired result. If it is still "springy" you should be able to bring the two ends inward until it bends a little bit and restore some of the clamping force. No need to go through a complicated heat treating process for something like that imho. It just looks like it's been stretched outward to the point where the band took a permanent set so it can't quite return to its original shape. Doing the same process in the opposite direction should get you back in business. Link to comment Share on other sites More sharing options...
Daswulf Posted July 3, 2018 Share Posted July 3, 2018 If you add your location there may be some local blacksmiths or blacksmith groups we could point you to. If you have nothing to lose its worth a try I guess. Link to comment Share on other sites More sharing options...
Gergely Posted July 3, 2018 Share Posted July 3, 2018 Okay Buzzkill just killed my buzz, and saved a lot of typing! Link to comment Share on other sites More sharing options...
DonutHands Posted July 3, 2018 Author Share Posted July 3, 2018 I did try bending it inward but it just springs back out without retaining its compressed shape. If i bend inward any more then the ends touch and would start to deform in the other direction defeating the purpose. Link to comment Share on other sites More sharing options...
Latticino Posted July 3, 2018 Share Posted July 3, 2018 With the information supplied my suggestion would be to work harden the band to a tighter radius. Since I have an anvil horn I would take my 1.5# ball peen and hammer the outside of the curve against an appropriate radius on the horn, consequentially leaving a nice hammer finish on the outside surface. If I didn't have an anvil I'd probably mount a piece of heavy steel pipe in a vise and hammer over that (say some 4" diameter schedule 40). IMHO you will kill it altogether if you try to heat treat it, but that is an alternative if you have the right equipment. Link to comment Share on other sites More sharing options...
Buzzkill Posted July 3, 2018 Share Posted July 3, 2018 2 minutes ago, DonutHands said: I did try bending it inward but it just springs back out without retaining its compressed shape. If i bend inward any more then the ends touch and would start to deform in the other direction defeating the purpose. It's a spring. They are supposed to return to a specific shape. However, nearly all springs can be bent when pushed past a certain point. Yours has been stretched outward past the point at which it will return to its original shape. To restore it you do need to bend it in the opposite direction to the point where it does actually deform (or reform) a little. I suggested doing that around something with a smaller diameter so that you avoid a sharp bend. Latticino's suggestion is a variation of that. In both cases the bending would be done on a rounded surface so that you don't introduce a sharp crease which will create a weak spot for it to easily break. In simple terms it's been bent. To correct that you need to bend it back in the other direction in a way that doesn't create a weak spot. You may have to kind of tuck one end inside the other to get the needed shape without bending the ends outward the way they would if you let them hit and keep squeezing. You might even be able to get away with something like a ratchet strap to get it where you want it. Like you said, if you can't fix it then it's going into the trash. If it doesn't work you are no worse off than you are now. Link to comment Share on other sites More sharing options...
DonutHands Posted July 3, 2018 Author Share Posted July 3, 2018 I guess I was hoping that i could compress it, then heat it and it would keep closer to that shape as its resting place instead of springing back. Hammering may work, but plain bending would probably ruin the ends which determine the angle the ear cups sit. Link to comment Share on other sites More sharing options...
Daswulf Posted July 3, 2018 Share Posted July 3, 2018 Since it's not something that is critical to save, I would heat them with a torch as mildly as possible to shape them around some pipe or to close them up a bit past where they need to be then once the shape is correct I'd reheat and quench in oil. If it "seemed too hard" (with the experience I have) then I might try to temper it back a bit. Thats just what I would try with what I have to work with. No promises they wouldn't break. Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 3, 2018 Share Posted July 3, 2018 I would not try hammering it against a horn or pipe but the opposite, hammer the inside curve into a negative space like a swage. You want to make it take a set to a tighter curve and that's generally easier hammering into a negative. For me I might use my screw press with 3 round bars two on the base of the tool and one in between on the top---welded to the plates of course. (I could also make a similar variation that uses a postvise with the rods mounted to angle iron. Investigate re-arching leaf springs cold Link to comment Share on other sites More sharing options...
Morrisonbryce Posted July 29, 2018 Share Posted July 29, 2018 Get tig welder run a bead in the middle on the inside on the band from out side to inside. Should not have to use filler metal just small puddle. It will cause shrinkage in that area causing it to close. (Controlled warp) Reference heat effected zones weldingtipsandtricks.com Has a video demonstrating heat distortion and how you can try to mitigate or control when welding. Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted July 29, 2018 Share Posted July 29, 2018 TP has the right of it. I would weld two round bars parallel to a plate, now placing the strap so the ear pieces are up one can use a strait pein to increase the curve in small areas. This will over come the limit of the ear pieces touching. I acualy have a hardy tool for just this but I am not near the shop. It is basicly a tuning fork laying on the anvil. Combined with my 3# 1/2 round strait pein I turn flat rings with it (think wagon tires) Thinking what a guy can do with out a welder and strait pein. It’s a one of deal, so one can use wood and either carve a grove or build up one say an inch and a 1/2 wide if you carve it and only about 3/4- 1” if you build it up. Now find a piece of round stock, say a pipe nipple you can beat down as a top die. Work it back and forth till you get it. Link to comment Share on other sites More sharing options...
stevomiller Posted August 6, 2018 Share Posted August 6, 2018 If they used SS, instead of plated carbon steel, you can’t HT it to make a spring. Generally they use 302 SS and it is work hardened as others here have encouraged you to do. Link to comment Share on other sites More sharing options...
Steve Sells Posted August 6, 2018 Share Posted August 6, 2018 Why cant a Stainless Steel be made into a spring ? Please explain Link to comment Share on other sites More sharing options...
the iron dwarf Posted August 6, 2018 Share Posted August 6, 2018 I have stainless steel springs but maybe they dont exist according to steve miller a friend works for a major spring maker and has springs made of titanium, glass and even concrete Link to comment Share on other sites More sharing options...
Steve Sells Posted August 6, 2018 Share Posted August 6, 2018 I know but Glenn gets upset with me when I call people out. I was told to try to be PC about it, and phrase it nicer and that I can not just tell them they are wrong and dont know what they are talking about any more. Link to comment Share on other sites More sharing options...
Frosty Posted August 6, 2018 Share Posted August 6, 2018 Good Steve, good boy! Have a cooky. There are only two requirements to be Stainless Steel. First be a steel alloy and it doesn't even have to be majority steel, Iron and carbon of some %. Second it has to be stain resistant and usually contains chrome or nickle to be so. If you couldn't heat treat stainless to make springs you certainly couldn't make knives from it. I have some kitchen knives made fro 440C and the fillet knife is darned springy. Everybody makes mistakes or learns data that is in error so not dumping on SteveOmiller is more than PC. It shows you have an understanding and kind nature. You're a credit to the Iforgeiron Admin. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Marc1 Posted August 6, 2018 Share Posted August 6, 2018 Come on guys, the OP is talking about a set of headphones, not a knife nor car springs. Those headphones are worth how much? Much easier to buy new ones than try to heat treat stainless steel with donuts hands ... and make a methol dry ice quenching bath not to mention buy an oxy acetilene set and set fire to the kitchen curtains in the process ... Link to comment Share on other sites More sharing options...
Steve Sells Posted August 6, 2018 Share Posted August 6, 2018 The point was never if its worth doing it. Much like most everything on this forum, the point was how to do it Link to comment Share on other sites More sharing options...
Frosty Posted August 6, 2018 Share Posted August 6, 2018 Heck Steve I thought the point of Iforge was to have a place to talk to blacksmiths. Even the ones with deliberately pointless comments. Frosty The Lucky. Link to comment Share on other sites More sharing options...
horse Posted August 6, 2018 Share Posted August 6, 2018 My suggestion is that if a post is too mundane, rote, or ignorant to be worthy of a sentence or two to explain just leave it alone. For example. "In my experience the are Ss alloys that can be beat treated to make spring Steel. Those are xyz if heat treated xyz, "could be a more generous response. There are more than a few smiths on this site that really just want to engage and are not certain how to get there. Try treating each person as a guest at your door and see how the tone might sound different. If the person at the door is an unknown sort but likely to annoy don't answer the door. I have done it n more than once when I was quite certain they were espousing some religious ideology I was not wanting to hear. For me this site is much more than technical information, it is a community that has its experts, yes idiots, and mostly curiosity about things they want to have a dialogue to better understand. Just my opinion of course. Link to comment Share on other sites More sharing options...
stevomiller Posted August 6, 2018 Share Posted August 6, 2018 Wow guys, Please excuse my previous kurt reply that did leave out plenty of pertinent information, I’m laid upon the couch full of meds because I am the owner of a back full of titanium. I don’t mind being taken to task, I should be, so let’s get that out of the way. But the holier than tho and assumptions you made about me and the ragdolling is uncalled for. Ive been part of this site for eight years, cut me some slack. And I don’t need a heybe kind by ignoring the ignorant fool at your door you wouldn’t want to talk to. I’m both a hobby knifemaker, hobby smith, and mechanical engineer by trade,:of course martensitic stainless can be heat treated to make springs. The reality in consumer goods industry industry, tho, is almost all coil an flexure SS springs are made of austenitic SS thats been work hardened. If you invert my two sentences and put the “most are made of 302” (and I mean springs like in a headset, or other basic consumer goods not tools or leaf and flexures springs in knives, etc) my point would get across. So yes, as I typed it you all are gloriously correct. However, none in you infinite wisdom picked up that at least I did mention the an austenitic stainless. So, yep, 400; 410, 416 And 420 as well as precipitation hardening stainless can be used as a spring. Again my words didn’t come out right and kindly calling me out would be reasonabl, at least Steve Sells asked for an explanation. However I’d wager a bet that as a mfg engineer I’ve specified more SS springs than the the rest of you poking me in the eye put together. Link to comment Share on other sites More sharing options...
Steve Sells Posted August 7, 2018 Share Posted August 7, 2018 YOU said SS cant be, we said it can be, Period. there was no qualification stated in your post. Also the OP has not returned since the day after he joined and posted this so he does not really care that much it seems, so why should we get bent out of shape over it? Link to comment Share on other sites More sharing options...
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