welcome viewers gee here welder professor educator guy who just really likes to weld stuff
and i'm here today because i want to talk about your chipping hammer and your chisels
so there's nothing worse than having a rounded off chisel or chipping hammer and uh you know
you can't do much with it so what happens we usually take it over to the angle grinder or to
the bench grinder and we sharpen this thing out maybe we put too much heat into it and we ended
up with a softer piece of material than than what we started with which ends up just dulling on it
again right so i've got a i've got a chipping hammer here that's really just good for nothing
because it's it's dull it's all rounded off i've got another chisel that's that's dull and really
good for nothing and i got another piece of raw material this is tool steel so i want to show
you how you can make your own chisel with you know some simple tools that you have in the shop
okay so before we get going on to building this thing or even sharpening your chisel there's a few
things you need to understand about some of these some of this type of steel that we're using to
remove material right so your chisel is actually a much harder material than say your your regular
carbon steel right so that's your mild steel right we call that low carbon steel so for instance
the real common uh tool steel is your 4140 and that's a higher carbon content which means that
it has a harder harder structure to it right and it is susceptible to heat treating
which means that we can either make this thing a little bit harder or a little bit softer right
through uh through something called quenching and tempering and that's what we're gonna do
right so but coming back to your chisel um the reason why i say you know you can't just go and
slam this into the angle grinder get it red hot get a nice uh a nice end on it and then go use it
again so it's what you're doing if you do that is you're actually softening up the material
so one thing we can do is re-harden this and then soften it out just a little bit so that
it's harder than the material but it's not going to crack either whenever we hit it so in this
video i want to show you a few demonstrations of what happens whenever we quench a material quickly
and then go right to using it okay i'm using two separate pieces of 5 8 round this is 4140 tool
steel and is considered chromoly meaning it's an alloy of chrome and molybdenum
in the first example i'm applying some brute force to my piece at room temperature i have not
heated it or anything as expected after repeated stress i'm left with a dented piece of round bar
let me demonstrate what happens to your material when it is heated to red hot and rapidly quenched
in water the rapid cooling of this material is going to make it very hard with less ductility
basically i've taken a perfect piece of engineered material and completely destroyed all of its
wonderful mechanical properties in a matter of seconds now that it's cooled let's go ahead and
put some stress to the end of our round bar i want to mention that safety comes first when performing
this kind of test i have a few layers of face protection and i'm well aware of my surroundings
after applying some brute force you can see that the piece has shattered and completely
failed now let's think about what happens when we leave a stray arc on a piece of material
or if we don't follow proper welding procedures a failed weld you're right
okay enough with the metallurgy lesson let's move on to building a chisel
one way to know when your material is ready to be quenched or tempered is to use a digital
thermometer this is the point-and-shoot type action for this application we want
to elevate the temperature to above 723 c or 1330 fahrenheit for clenching this temperature is known
as your lower critical temperature or transition temperature this is where your material begins to
lose its magnetism after this we then heat it again below 723 c or 1330 fahrenheit to temper
this is where things like annealing normalizing and stress relieving take place
these are all different forms of heat treatment something less expensive like a temp stick can
be used you would apply the stick to the material when it melts you are at the required temperature
temp sticks are often used when preheating and post heating materials okay let's have a look at
our color chart this chart can be used to identify temperature ranges for heat treating carbon steel
when steel is heated it will naturally go through a temperature change this change will
reflect in different colors so those pretty colors you see are not the different alloys
it's telling you something important for this application we want our material
to be red for quenching and a tan to blue range for tempering okay let's have a look
in this example i'm going to depend more on the colors from the steel for the tempering process
here you can see me gently adding just enough heat to have my steel turn purple
about halfway up the piece i then watch for the tan or yellow color to grow into the end
when it's time to cool your material it can be done in a few ways this will depend on the
application for this chisel i like to let it cool in normal conditions at room temperature
or if i want something a little softer i can have it cool slowly in the oven or even on top of the
oven most of the time letting it cool in the still air is enough this is called normalizing
okay so before we do any heating let's have a look at what we're going to need for safety
obviously going to need some gloves to protect your hands
i've got my shade 5 cutting glasses right now the bright light from the oxy fuel
can uh can damage your eyes and just to point out here if you've got oxy propane or oxymab gas or
whatever it is you're using this will be the exact same process okay so the next thing you're going
to need is you're going to need yourself a pair of locking pliers or some form of channel locks vice
grips uh whatever the case may be to hold your piece all right and beside me i've got two options
here i'm pretty lucky i've got the option of using the cutting attachment on my combination torch
or my small little cute little rosebud and i think that's what i'm probably going to use
this is fairly thin um you know we're looking at about uh some half inch thick
round here and this will definitely be enough okay so now that we've got our torch hooked up
it's time to uh set our regulator so this may look a little bit different to you or not i'm just not
running on two bottles a bottle of oxygen a bottle of acetylene i'm running on a manifold system that
means that the gases are being delivered they're being piped in from another area i don't have to
worry about opening my oxygen bottle in full you know and my acetylene a quarter to a half turn
i've got two levers that i can open up right now right and that's going to start delivering gas to
my regulators all right so i've got t handles on this i'm going to set my acetylene to about 5 psi
and then i'm going to set my oxygen to about 20. now a couple things to recognize here on
on our system we've got check valves and flashback arrestors right check valves allow the gases to be
uh flowing in one direction only and then our flashback arrestor is another safety device
whereas if the gases do decide to ever kind of come back into the lines these little devices here
are going to extinguish that uh that flame i'm using some 4041 tool steel so this is hardenable
carbon steel this means that it's going to react to the heat whenever i whenever
i apply it whenever i quench it whenever i put it in water rapidly okay so you can't do this
with just regular carbon steel so just mild steel that's not going to happen you need to have some
form of tool steel somehow some form of medium to uh high carbon steel for this okay so i've got my
rosebud set up let's uh let's go ahead and light our torch and then um i'm gonna have my torch here
and i'm gonna go ahead with my 20 ounce hammer and i'm going to start shaping the end of my chisel
i was having difficulty seeing through my shade 5's
which was a bit of a safety concern i decided to change to a clear lens
for shaping i'm hammering down and away from me at the same time this will give me the tapered
look to a chisel that i want i'll rotate 180 degrees and do the same on the opposite side
every so often i will rotate it 90 degrees and strike it on this side to keep it similar in
width this process will come with practice by the end of it you'll be doing it like a pro
okay now that we have the desired shape it's time to cool it and finish it on the grinder
so now that i have my chisel shaped to the shape that i want i'm going to take the torch i'm going
to heat it up again i'm going to heat this tip up again and i'm going to quench it right so that's
going to give me the hard tip that i want right so i'll take it and i'll give it a final shape and
we'll get it nice and shiny and then i'll bring it back to heat it up below the critical temperature
and that's going to give me the right softness the right hardness that i want for a working chisel
turn off our oxygen and our acetylene
for this application a straight water quench is used i chose water because it is inexpensive and
available it's important to note that not all materials will behave the same when quenching
a water quench is the most rapid and aggressive quench and in some complex
materials can be susceptible to cracking other quenching medias can be used such as salt brine
oil polymer liquids or even air quench which may be less prone to cracking
okay so i got her nice and cool now
i'm going to take it back to my sandpaper i'm going to take it to my buffing pad i'm going to
finish this off i'm going to get it nice and shiny so i can bring it back and anneal it
now that we have our homemade chisel let's move on to our chipping hammer and store-bought chisel
this process entails the same steps as the chisel build
except for the shaping portion the first step is to remove any paint or coating on
the hammer you need to be able to see the bare metal when tempering our tool
on the angle grinder this is me removing paint with a flapper wheel you can also do this on the
bench grinder i'll do the same to our store-bought chisel okay so that looks pretty good right now
now that i have the paint removed off the end i'm going to take this over the bench grinder the
pedestal grinder and i'm going to reshape the ends but i don't want to put too much heat into this
so i'm just going to gently sort of grind out what i need and this is going to be sort of a
preliminary grind all right the next step will be to take it over the torch we're
going to heat it up red hot above the critical temperature and we're going to quench it in water
and then from there we're going to reshape it one more time and then take it back to the torch
and sort of apply a little bit of heat enough so that it gets golden golden yellowish a tan a straw
color we're gonna let that sit i've got my new chisel here over at the device with a piece of
1 8 mild steel and i'm just going to dig into the corner here and see what we can do
so we can tell here that it didn't even neck it didn't damage it at all so that's a good sign
look at our piece of mild steel you know we can tell that it got gouged pretty good
okay so there you have it folks there's your quenched and tempered materials you
know i've taken my my chisel and my chipping hammer i resurfaced them i re-hardened them
uh my chromoly or my 4140 i took it from scratch i shaped it i quenched it you know i finished it off
and then i tempered this piece one thing i want to mention is that we're working on the end of this
chisel okay you don't want to be doing anything to the top of this you especially don't want to be
quenching this part and making this hard we're striking this end it's uh it needs to be a little
bit softer than the rest of the material otherwise it'll shatter because we've seen that in the
in the first example that i demonstrated right so you know i would say anything above here
80 90 of of this chisel is uh should be unaffected right you know you might get a little bit of
difference here um where we're heating up the chisel but especially the end be careful there's a
reason why that end mushrooms on us right it will get consumed eventually so make sure we're cutting
that mushroom off uh we're getting rid of those pieces if they're uh they're in your way so on
our chisel and our chipping hammer right um again this is something we can do periodically you know
every every now and then if you find your your chipping hammer is getting soft you want to avoid
taking it over the grinder and slamming a bunch of heat into there because essentially is what
you're doing is you're you're almost tempering that right you're almost annealing that again so
means that you're softening up the material so if you're going to if you're going to resurface this
piece you know keep some water close by maybe some oil and you want to just grind softly and
not put too much heat into it so you don't affect it okay so i hope you enjoyed this video everybody
that's your quenching and tempering uh keep your lenses clean and be safe out there