Im thinking on making a pry bar from a truck axle. Question is do I need to annel the bar and harden only the working ends. Or can I leave the whole thing the hardness that it is?

Thanks,
Pj

I would think you have to anneal the whole thing, then forge to shape, then reharden and retemper the whole thing.

You do NOT need to anneal a truck axle to use it. They are tough, not brittle, and will take a LOT of abuse. All you have to do is forge the ends the way you want them and do a generalized heat treatment for whatever your application.

You don't have to harden the whole thing. In fact, it is better if you leave the body alone. For the average blacksmith, hardening an entire shaft consistently is nearly impossible. Never mind getting an even temper through its length.

A pry bar or digging iron just needs a hardened tip. I moved my 6,000 pound power hammer around using a truck axle pry bar. I deliberately left it a bit soft because I'd rather the end bend a little than snap.

So my recommendation is to forge the pry bar, let it air cool, and try it out. If it is still too soft and bends too easily, heat the business end to bright orange and quench in oil. If it is still too soft, do a water hardening and temper back to blue. One problem with trying to heat treat an axle at home is that unless you know the specific steel alloy, it is all guesswork. That's why I recommend the least brutal heat-treating methods first.

The one small scale industrial forge that I visited he forged the ends and allowed them to air cool in a shoping cart with the rest of the run. Pry bars are normally made of tough simple steels, normalizing should be sufficient. If you want to harden an unknown steel, try air cooling first, then hot oil, then water, then brine. (if I remember correctly brine is a faster, harder quench than water?" Then lye, or superquench;-) Thin cross sections tend to be more shocky, and likely to quench crack in too fast a quenchant... Remember to only protect those body parts you would like to keep... Think safety glasses, and gloves at a minimium...

BP0164 Small pry bar
BP0165 Pry bar from car parts

I would prefer ANY bar to bend rather than break. When a bar breaks, you are usually off balance and end up on the ground, and the bar throws both big and little pieces of shrapnel. If the bar is "soft", only the bar suffers a case of the bends.

We need some help from the engineering types on calculating the pressure on the opject when using a pry bar. Show us the formula and give us an example to work with, say a 32" bar and a 100# pull at a 2" fulcrum. What happend when we use a 62" bar instead?

Ooouuuhhhh, my brain.
Gobbler

yes just let it air cool make sure it isnt in a draft on the floor ,or on a cold steel plate , if its a cold day slide it into a steel pipe to lessen chilling .well every one at home seems to think i need a holliday and i am doing to mutch so to keep the peace ,im of to do nothing ,i thought i have had plenty of that for the last month or so ,still orders are orders,

you don't need to be an engineer to figure that out, just common sense and a bit of math.

Considering the object to be moved is of unkown weight, and there is a distance of 2 inches from the edge of the object to the fulcrum, divide the length of the handle by 2 and then multiply that number by the weight applied to the end of the handle. 32 inch bar - 2 inches fulcrum - 1 inch under the object = a 29 inch handle, considering the center of your hand (the applied force) is 3 inches from the end leaves 26 inches divided by 2 = 13 times the distance from fulcrum to object x's 100 lb = 1300 lbs of applied force at the lifting point of the bar.

I used this formula all the time to find out if I could lift an object of a known weight with my winch trucks.

Ooouuuhhhh, my brain.
Gobbler

OOOOOOOOHHHHHHH mine too.

I never use any formulas, if it don't go, get a bigger, longer pry bar!!!..LOL

I never use any formulas, if it don't go, get a bigger, longer pry bar!!!..LOL

Now there's another person that thinks like me!

Sometimes it's easier to do the math though, that way it saves you multiple tries. In my case I'd probably forge each one of them and have to do it 3 times! :rolleyes:

Man guys I was away for awhile and come back to bukoo info.......
Thanks..

Pj

On 10/20/2006 at 11:46 AM, KjZitur said:

I never use any formulas, if it don't go, get a bigger, longer pry bar!!!..LOL

I am a mechanical engineer, and can do the math, but when I'm actually getting a job done, this is what I do too!

I do love an engineer who knows what his blood looks like on his own tools. Being an ex mechanic, other engineers not so much...

We used to say in the sword shop: "Every major blade gets baptized in the maker's blood."

But I've worked on things where the designer should have been forced to service it their-self before they got paid for it!   Then we might not need so many half thickness wrenches and ratchets with a U joint, deep wall sockets, and of course, the proverbial dirty shop rag to wrap you hand up in on the way to the ER ...and I'm not a Mechanic! 

ER?!? Pa-shaw,  just set the bone back in place with a good whack on the table then wrap it in a piece of paper towel soaked in alcohol then use some black tape to keep it all in place and to get the bleeding to stop. Then go back and finish pulling the trans out of that bucket truck. 

Unless the SO is nearby and you hear sirens before you stop dancing and cursing. Been there.