altering the shape of some pliers

[Grandpapajim]

Hi,
I know little about blacksmithing but I need some help.
I want to alter the shape of a pair of 8

[easilyconfused]

Not much to add in the way of hints or tips. I'm a free hander who follows the "close enough" method on the farm. Have you drawn out what you want the jaw to look like so you have measurements and a set curve to compare it to? Since you're grinding, I'd make sure to take it slow and keep checking the match regularly. I'm assuming the blackened metal isn't soot that can be wiped off? I wouldn't quench them in water after working on them without knowing the steel and the heat you're using and a knowledge of heat treating. Techincally it won't weaken the metal but it may break because it's too hard and become brittle. Depending on how shiny you want the metal, a soak overnight in vinegar might be enough. To get a full mirror shine back, you'll have to polish it up with progressively finer grit sand paper and buffer in the final stages.

Hope this helps a bit.

[Grandpapajim]

Thanks for that, I am going to try the vinager trick first, I will keep you posted. Someone sugested quenching it in Oil to give a dark finish and prevent rusting???? Ever heard of it?

Regards
Jim

[Mills]

For rough shaping having the work in the vice and grinding is good. Next put a belt sander in the vice and use it to finish it to the shape you want. I also use the angle grinder with fiber discs sometimes but it is much less controllable. Once you have the size and precision you seek then heat and and bend to the desire shape. You may need to make a jig to get things identical.

To avoid using up a lot of pliers I'd suggest some mild steel to work out the process with.

Once you have the shape, quenching in oil is a good first step to get back to hard without being in danger of breaking it. Next is to bring it to a good temper. Using the belt sander again polish up the piece so that it is shiny. then heat SLOWLY til the colors run. Again I would use mild steel first to see the changes happening so that you will be ready for it. Heat until you get a nice deep yellow to purple color then quench in oil, shine it up and run the color the same way again.

Now there are a LOT of gaps in this procedure that we aren't covering. This seems to be your first heatreating attempt. If you have no success ask more questions, but you may also want to search this site for heattreating information to get a better feel for what you are wanting the steel to do.

[Grandpapajim]

Thanks Chaps,
I like the "Close Enough" method; that will do me. I tried the vinegar and it really worked surprisingly well, but not quite good enough so I will try sand paper. I drew out the shape I wanted and followed it by offering it up between hammers it now looks just as I want it.

Can’t find any info on hardening the tool. If I heat the tool up to red hot and then let it cool naturally will that harden it? Or do I have to get it red hot and then quench it in water or oil to harden it? I tried to find some info on this subject but no success so far. PS I am working with “Dropped Steel” whatever that is.

Thanks again for you advice, appreciated.

Regards
Jim

[Mills]

BP0078 The Metallurgy of Heat Treating

[ThomasPowers]

Thats Drop Forged Steel; doesn't tell you anything about what type of steel it is; just how it was manufactured.

Without knowing what the ALLOY is you are just guessing on heat treat. Heating till a magnet will not stick to the hot metal and letting cool in still air is normalization and will generally leave a plain high carbon steel tough but not brittle.

Pliers are probably not high carbon steel; but may be medium carbon steel. If so heating as above and quenching in warm oil will probably harden them and then you need to draw temper to probably 400+ degF; shine the piece up with sandpaper and heat till it turns somewhere between peacock to blue. Blue is softer tougher, peacock is harder more brittle so depending on the ALLOY and how brittle/hard it gets in oil you choose what temper you want to go with.

If they are low carbon steel, heating as above and quenching in water *may* help slightly; but in general a true low carbon steel can't be heat hardened very much at all.

[easilyconfused]

I'm not sure about the actual alloy used, but for most of the common steels above mild, an oil quench is "close enough for the farm". There are many threads on heat treating in the forums and especially on bladesmith forums if you want to read up on it just incase I'm not remembering 100% correctly.

To start with, you'll want to heat your steel up past the critical temperature. The easiest way IMO, is by checking it with a magnet on a string. Once it is no longer magnetic, then you let it cool slowly. For most stuff air cooling is fine but leaving it by the fire works better or you could pack it in some ash to cool it even slower. The key to normalizing/annealing is to cool it back down slowly. After it's cooled off, then you harden it but heating it back to nonmagnetic and quenching it. Water cools faster and therefore gives a harder quench than oil and can make some of the higher tool steels crack due to brittleness, hence why most people use oil. Of course this is variable with other factors like the size of steel you're working with as larger pieces may need water to cool fast enough to harden the center too.

Tempering after hardening can be done a few ways, depending on what you're using it for and how picky you are. When I'm making tools for the forge I usually do the hardening and tempering in one heat by heating past the part I will quench to harden and let the residual heat temper the hardened part. This only works with stuff that you want one end hardened and the other end soft with a gradient between, like punches or chisels. I don't know how it would work for pliers as part would be soft.

Another method is to slowly heat the metal up after hardening to the proper temperature, either in the fire, oven or with a large torch for smaller pieces. and then quench it. There are charts floating around the internet and various books as to what the different colours are in respect to hardness for various tools. They range from a staw yellow to blue-purple as hardest to softest temper. Once again the harder it is, the more likely it is to chip or break but the stronger it is.

I'm not as fancy and I know I'm missing stuff so hopefully others who have more experience will chime in too.

[IronPuppet]

I assume you want the tips to mate after you bend it. This is how I would do it.

Once ground to shape, close the pliers and clamp the end of the jaws in a vice so as to hold them fast together. Handle sticking upwards. Heat where you want the bend to be and once hot enough use a tool to slowly bend the handles down to where you want them. Let cool in the vice and once cool, reheat for heat treating. this will automatically assure that the ends of the tool remain in a mating position.

I would put the torch on the tool as I bent it to keep the heat up.

IP