What are Crow Bars made from?

[stuball48]

I'll bet Charlie Weaver of "Hollywood Squares" fame would have been a favorite if he had been a member---I see his "one liners" being used in this forum quite often.

[Troup]

Originally Posted by Cory

They are hardened but is it case hardened or tempered?

Cory

It's probably safer to use the term "heat treated" rather than "Hardened" in the general case.

The objective of heat treating a crowbar is to attain the highest possible core strength, and this will be a little different in procedure and results from a heat treat with the aim of maximum surface hardness.

Case hardening is almost never used where core strength is the goal.

The crowbar will inevitably end up with a harder surface when heat treated for max strength, but nowhere near as hard as it could be.
So to answer your question, it would be 'heat treated and tempered'

The forging process would have refined the grain, which is a desirable precondition for toughness (and will have provided a modicum of workhardening, but that will be superseded in the heat treat)

[Cory]

Thanks for all the info so far. I seeso many people talk of many different steels to make a prybar. How about 4140 is this not good enough or strong enough to make a prybar? Please explain.
Thanks,Cory

[lathehand]

To continue the humor: a friend calls it a "rooster bar." When asked he says "Doesn't a rooster crow?"

Carl

[Flatus]

Originally Posted by Cory

Thanks for all the info so far. I seeso many people talk of many different steels to make a prybar. How about 4140 is this not good enough or strong enough to make a prybar? Please explain.
Thanks,Cory

i suggest S7 or A10. But they dont taste so good. It all depends on what you want to do with this crow bar. I'm assuming killing zombies and starting fires.

[DMF_TomB]

Crow bar metal
Carbon Steel 1045 which is hardened and tempered for High Yield strength like a spring would be. Common for concrete rebar and machine shafting.

Carbon Steel up to 1095 could easily be used.

Chrome Vanadium Steel alloy are used on wrenches as it is stronger.

Also W-1 water hardening, O-1 Oil hardening steels are being replaced with Air Hardening steel. Why is, heat treatment hardening and tempering is done with Computer controlled furnaces and air cooling is easier to do. Also warpage is less with thinner material. And decarb layer (lower carbon outer layer) is easier to control if everything is done (heat treatment) in the furnace.

Alloys are often picked for ease of manufacturing as much as as for tool usage.

[anchorman]

Originally Posted by Cory

Thanks for all the info so far. I seeso many people talk of many different steels to make a prybar. How about 4140 is this not good enough or strong enough to make a prybar? Please explain.
Thanks,Cory

I don't see why not. I made a bigass pry bar out of 1" diameter 4140 hex stock about 6 feet long. made short work out of lifting the bridgeport mill so that it could be blocked up and moved across the room.

easy enough to forge 4140 if you have a forge, and I am not a particularly talented blacksmith.

I didn't bother to heat treat, but I was not using it in a situation where it needed it. cold forging the end a bit as it was cooling down probably work hardened it enough for what I was doing.

If I were making a real crowbar for carpentry or the like, I might try and heat treat it properly (harden and temper).

[knudsen]

Originally Posted by Cory

Should I retitle my thread to PRY BARS?

That would only encourage the peanut gallery.

[bryan_machine]

"Any tool steel will work, and 1018 certainly would not work."

I get why any tool steel will work (ductile -> won't fracture)

What would be wrong with 1018? Is it particularly brittle or something? Impossible to temper?

[surplusjohn]

I have to look up that Jim Crow refererence. As far as Titanium goes. I knew a guy back in 91 or so, who was Polish and was buying Soviet surplus in Poland and bringing it over here. One thing he bought was 1,000,000 army helmets for scrap, and aparently for little money, you guessed it, they were titanium.
The Johnson bar should of been named the knock your teeth out bar.

[Ferrous Antiquos]

Originally Posted by surplusjohn

The Johnson bar should of been named the knock your teeth out bar.

John, I'd like to hear the story that prompts this statement. I treasure my J-bar, but my dentist is in his mid-80's and getting a little shakey.

[boslab]

yoy can make them out of just about anything you like and they still bloody bend when thier not supposed to.
my favourite is a antispark one from a refinery, berylium bronze is the stuff, theres no reason why either grade isnt used for a simple lever, in the end cost usually decides
mark

[Rick Rowlands]

Thats because even the Chinese forge shop that is selling them to McMaster doesn't know either!

[KIMFAB]

I have made some pretty respectable flat bars out of spring steel.
Go to your friendly 4 wheel or suspension dealer and get some spring steel, heat it up, put your bend in it and then starting at one end bring it up to bright yellow hot.
Let it cool and you are done.
If you want something with less spring try an axle. I still have a 5' bar made by my grandfather out of an old model "T" axle. It has moved many machines and is still going strong.

[SouthBendModel34]

"another note about crowbars, i have seen good ones shatter when dropped from 15-20 ft onto a concrete floor if the temp is down to
around 10 degree's F below zero. so contrary to popular belief they can be killed under the right conditions."

Aha! The infamous "Nil Ductility Transition" strikes again !!! RMS Titanic 1912, USS Ponaganset Boston 1944, the big oil storage tank in Jefferson PA that burst into the Ohio River on Jan 2nd 1988 - the list is long. There's a whole slew of commonplace steels that will BREAK LIKE CAST IRON below a certain temperature. Look it up !

Here's a good story about the scope of that oil tank disaster, although it doesn't seem to include an ID of the steel:

http://www.maintenanceresources.com/...mechanisms.htm

The scary thing is that the temperature below which a steel may display zero (nil) ductility can be above the freezing point of water in some alloys. It does not have to be 10 degrees below zero F.

John Ruth

[Caspian]

why not get the info straight from the Crows mouth and call Mayhew Tool in Mass. They'll probably tell you. It's not like you're going to start a forge and heat treat company and steal thier info.

I toured thier factory a couple years ago and they make chisels, pry bars, and a few other nice tools. You definitely see the quality that goes into US tools. Just got back from a visit to Klein Tools. Same great US quality goes into thier products. Refreshing to see.

[Forrest Addy]

What are crowbars made from? Crowmium alloy of course.

[boslab]

Originally Posted by SouthBendModel34

"another note about crowbars, i have seen good ones shatter when dropped from 15-20 ft onto a concrete floor if the temp is down to
around 10 degree's F below zero. so contrary to popular belief they can be killed under the right conditions."

Aha! The infamous "Nil Ductility Transition" strikes again !!! RMS Titanic 1912, USS Ponaganset Boston 1944, the big oil storage tank in Jefferson PA that burst into the Ohio River on Jan 2nd 1988 - the list is long. There's a whole slew of commonplace steels that will BREAK LIKE CAST IRON below a certain temperature. Look it up !

Here's a good story about the scope of that oil tank disaster, although it doesn't seem to include an ID of the steel:

http://www.maintenanceresources.com/...mechanisms.htm

The scary thing is that the temperature below which a steel may display zero (nil) ductility can be above the freezing point of water in some alloys. It does not have to be 10 degrees below zero F.

John Ruth

Nice to see it noticed, its a favourite of mine after suffering it in university for a semester, artificial depression of the brittle/ductile transition by the element phospherous [in particular] and the historical significance, i was particularly impressed with the presentation that was given by kaiser about the building of the lLiberty ships and how they failed.
seems some manufacturers havent learned, would think crowbars would not be suffering but that does not seem to be the case, bet they didnt think about sub zero operation!!!!!
regards
mark

[mobile_bob]

after seeing one shatter at low temperature being dropped, it sure
has made me stop and think before leaning hard into one using it normally at similar temperatures.

like maybe i will warm this baby up a bit before i trust my life and limb to it and use it in a manner that might get me injured should it fracture.

bob g

[NTM]

The ideal material will be a steel that maximizes toughness at a given (lower) hardness, such as a lath martensite forming steel over a plate martensite former. This rules out W1 and 1095 because the high carbon content (and also processing difficulties due to requiring a very fast quench to prevent pearlite - less than one second to get from 1500 to under 900F). This also rules out 1018 - because it won't form martensite - too carbon lean, can't be hardened.

A steel with a carbon content between .40 -.60 would be ideal. And a tough alloy steel would be best. 4140 and 5160 come to mind.

Contrary to popular belief - forging doesn't do much for grain refinement because the forging temperatures needed to prevent intergranular fracturing are also hot enough to cause excessive grain growth. The best way to achieve fine grain involves thermal cycling. 4140 would be brought to 1600 to even out the carbon and elements and promote an even (though large) grain. Then it would be air cooled to room temp and heated to 1550 - then again to 1500, then 1450. Each lower reheat partially melts grains, which forms new smaller grain upon cooling, setting the microstructure for a good hardening heat. It would then be austenitized at 1525, quench in a fast oil (such as an 11 second quench oil) and tempered to 400 F for a hardness in the 40s. That will be one very strong pry bar.

A higher carbon steel like 5160 would require careful attention to prior heats to control where the carbon is - and a lower austenitization temperature to reduce carbon in solution during quench in order to achieve a high percentage of lath martensite formation.

High carbon, like 1080 -1095 could be used - but are really not the right material.