No announcement yet.

Heat treating wrenches

  • Filter
  • Time
  • Show
Clear All
new posts

  • Heat treating wrenches

    I need some cone wrenches for working on my mountain bike, and I was thinking about cutting some out myself. It would be pretty easy, and I've got a bunch of random steel laying around. I'm unsure as to how to temper such an item though. Any suggestions?



  • #2
    Cut them out of an old circular saw blade such as a plywood blade - something that does NOT have carbide teeth. Then you have a chance of hardening them. Heat until they are non-magnetic, probably oil quench, then reheat to maybe 450 or so.

    For the $5-$7 that they are asking for cone wrenches, you'd be better off buying.
    --- RJL ----------------------------------------------

    Ordinarily I'm insane, but I have lucid moments when I'm merely stupid.


    • #3
      Small leaf springs work too if you need something thicker; they'll harden (step 1) and temper (step 2) also. You can't temper something unless it's been hardened and if you harden without tempering, it'll likely be so hard as to be brittle and break. Not easy, maybe you should buy them until you've practiced on a few pieces.
      Stickmate LX AC/DC
      Big cheap (Chinese) Anvil
      Hand cranked coal forge
      Freon bottle propane forge
      HH 210 and bottle of C25


      • #4
        I'm with usmcpop. Unless you are just wanting to play around, buy some wrenches. The saw blade and leaf spring will work. If you are going to use mild steel forget it. It can't be heat treated. It will work harden a little but still won't be good for a wrench.


        • #5
          About the only way you can even slightly harden a relatively low carbon steel (say 1018) is to do a "violent" quench in something like a strong sodium hydroxide (lye) solution. Rather nasty stuff to work with and you still end up with a relatively soft and weak steel.

          cone wenches?

          Last edited by usmcpop; 01-30-2009, 12:37 PM.
          --- RJL ----------------------------------------------

          Ordinarily I'm insane, but I have lucid moments when I'm merely stupid.


          • #6
            Sounds like I'm a conehead for even trying this, but I don't mind playing around in the shop for any reason. The wrenches need to be thin in order to fit between the flanges on the cone and the holding nut, and they don't need to supply the kind of torque you would expect from a normal open end or combination wrench. If I were to endeavor to make such an item what temperatures would I need to raise the steel to alter it into a reasonable product? Or, where could I find this information? How would the lye solution chemically affect the metal? As always, thanks a ton for the information.



            • #7
              You can also buy a normal open end wrench and grind it thinner. I've done this for odd size wrenches where a thin wrench was needed, but couldn't be easily found. I tend to use cheaper wrenches for these, as even Sears might not take back a wrench that has been modified this way. (Then again, they might.)

              Still building my new old truck - see the progress!

              Square Wave TIG 200 - Woot!


              • #8
                You first need a high carbon steel. Buying it new would be more expensive than buying the wrench.

                You could use used steel but since you don't know what type of steel it would be, you would surely not heat treat it correctly, but may do a good enough job to make it workable.

                Bed frame rails are carbon steel, I have heard they are 1095 or 1084, not sure.

                You could make your wrench from these rails.

                Do whatever you have to do to get the piece to shape. If the steel is too hard to cut, build a fire in the back yard and get a good bed of coals, bury the steel in the coals and let the fire burn out slowly. The longer it takes to go out the better. This anneals (makes it soft) the steel. Now profile your tool to shape. Leave it just a bit larger than wanted so you can clean it up after heat treat.

                After you are done and ready to make it hard again and since you probably do not have a forge or heat treat oven, you can use an oxy/acyt torch to heat treat.

                Heat a gallon of transmission fluid to about 125 degrees and have it ready. Have a lid ready also in case of the oil flaring up, which it will do but it will go out fast also but be ready in case it does not.

                Get a fairly strong magnet with a handle of some kind, glue a piece of wood to it if you have to.

                Heat your metal up evenly and slowly. Keep checking it with the magnet. The magnet will stick to the hot steel so get it off quickly. Keep heating and checking until you get the steel hot enough that the magnet does not stick. Heat it just a bit more. You want the steel about 100 degrees hotter than when it stopped being attracted to the magnet. If you do this fast you can end up 400 degrees to hot, do it slowly.

                After you get to nonmagnetic plus about 100 degrees, quickly dunk it into the oil. Don't swish it around or anything, just hold it there for a minute or so. When you pull it out it may be smoking, if so put it right back in and wait until it is cool enough to touch.

                Now go the the kitchen and wash it with soap and hot water. Get all the oil off and put it into the pre-heated oven at about 400 - 425 degrees (don't trust your oven T-stat, use a good one). Let it cook for about an hour and turn it off and allow to cool to room temp, repeat two more times.

                Now go back to the shop and clean it up and you should be good to go.

                Lots of work when you can buy one under $10 but at least you can say you made it yourself.

                Tumbling down the road at 35 MPH is no fun, TRUST ME!


                • #9
                  Jersey Shore Steel rerolls old railroad track into various posts and, at one time, bed frame material. They say their steel is typically .65% carbon. I have seen pictures of bed frame material fashioned into a woodcarving gouge.
                  --- RJL ----------------------------------------------

                  Ordinarily I'm insane, but I have lucid moments when I'm merely stupid.


                  • #10
                    Jeez guys, these wrenches get something like a few inch pounds of torque. Mild steel would be just fine, no hardening needed. If you get excited and use a piece of spring steel just heat it to non magnetic and quench in water. Done. I have made may punches and tools out of automotive coil and leaf springs and found that if I harden and quench in water they last a long time. If I temper them to a light straw they lose their edge quicker. I have never had one break. This isn't tool steel and doesn't get as hard when hardened.
                    Chief slag chipper & floor sweeper
                    Ironwood Artistic


                    • #11
                      Heck! Just try cutting/grinding your shape out of some old junk Circular Saw blades. Forget the hardening. For a few inch pounds, they should work....more of a challenge to your layout and final grinding skills. Just take an existing cone wrench and trace it.
                      "Good Enough Never Is"


                      • #12
                        thin some ordinary wrenches with a grinder. Make sure you use your water dip often to avoid losing the original temper of the steel. I've done it many times for other difficult to reach applications. (Adjusting gripper on cylinder of Multilith duplcator is one that comes to mind.)


                        • #13
                          I made a wrench using some old lawn mower blades. Had to use cut off wheel
                          though to make the opening.
                          Hobart Handler 175
                          Miller Thunderbolt AC/DC
                          with Tig torch and Hi Freq.

                          Miller XMT350 CC/CV
                          Miller Suitecase 12RC
                          Miller Spectrum 1251
                          Miller Syncrowave 250
                          Miller Dynasty 200 DX
                          Miller Goldstar 652


                          • #14
                            I might cut an old saw blade if I was in a pinch but the project is pretty much an exercise in mental masturbation. It must be something to do with the bike crowd??? hahaha,,, I got friend like that, want to build a stainless deal when a 12$ garbage can would do.