1929 Model A leaf spring steel

Joined
Jun 9, 2020
Messages
7
What’s up everybody? I was just given a set of leaf springs from a 1929 Ford Model A and wanted to make some knives with the steel. Does anyone know for sure if these particular leaf springs are definitely 5160? I assume they are, but was just curious if anyone knew for sure. Thanks in advance!
 
What’s up everybody? I was just given a set of leaf springs from a 1929 Ford Model A and wanted to make some knives with the steel. Does anyone know for sure if these particular leaf springs are definitely 5160? I assume they are, but was just curious if anyone knew for sure. Thanks in advance!

Be best to ask in the maker's subforum. You can report your post and ask to have it moved.
 
In his early cars, Henry Ford used a high vanadium steel. If I was to venture a guess, it was something similar to 1080V. The only way to know would be to have a sample tested.

That said, it is surely a good knife blade steel. I would suggest normalization after forging the blade and then a HT with these parameters:
Austenitize at 1475 to 1500°F with a 5 minute soak
Quench in a fast oil or canola.
Temper twice at 400°F for an hour each temper.
 
In his early cars, Henry Ford used a high vanadium steel. If I was to venture a guess, it was something similar to 1080V. The only way to know would be to have a sample tested.

That said, it is surely a good knife blade steel. I would suggest normalization after forging the blade and then a HT with these parameters:
Austenitize at 1475 to 1500°F with a 5 minute soak
Quench in a fast oil or canola.
Temper twice at 400°F for an hour each temper.
Thanks for the input. You kind of echoed what one or two other people told me as well. When I temper, I usually go twice at 400° but for 2 hrs each time instead of one and have gotten good results. Do you recommend the 1 hr temper times because the steel is so old, or is that just what you usually like to do with 10XX steel? I know tempering isn’t an exact formula and people do things in different variations of what we’ve both mentioned.
 
...Also, I know there are a couple different schools of thought on this. If I go with just a stock removal, would you normalize anyways even though it wouldn’t have been beaten and put under stress from forging?
 
Yes, normalize even if stock removal, just to bring the steel back to a known state. You don't know how Ford heat treated it, better to start fresh.
 
Ford would not have heat treated this steel. As it sits now, the leaf springs are not hardened steel. They need to be that way in order to be flexible for the car. However, I guess it couldn’t hurt to normalize and realign the grain structure b/c of the wear and tear and any stresses put into the steel as it was driven etc.
 
Ford would not have heat treated this steel. As it sits now, the leaf springs are not hardened steel. They need to be that way in order to be flexible for the car. However, I guess it couldn’t hurt to normalize and realign the grain structure b/c of the wear and tear and any stresses put into the steel as it was driven etc.

they are heat treated, otherwise they would just bend, and not spring back.
 
So you’re saying they’re heat treated, but not to the point where they need to be annealed? They’re obviously not harder than a file. I’m sorry for sounding unfamiliar with leaf springs, but this will be my time using them. Usually I just work with pre-annealed flat stock such as 1095, 1084, O1 tool steel that I get from a supplier.
 
No, they won't be harder than a file. A spring is fully hardened, then tempered back to increase toughness. It will be too soft for a proper knife, but very difficult to work in its current state.
 
I understand now. Thank you for clarifying. So, they are hardened, but soft enough through tempering that they don’t need to be annealed. However, they’ll definitely need to be quenched and tempered again.
 
If you have a furnace, I would heat them to 1250’f for two hours before working them. This is a subcritical anneal and will be a good condition going forward.

Hoss
 
So you’re saying they’re heat treated, but not to the point where they need to be annealed? They’re obviously not harder than a file. I’m sorry for sounding unfamiliar with leaf springs, but this will be my time using them. Usually I just work with pre-annealed flat stock such as 1095, 1084, O1 tool steel that I get from a supplier.

heat treated is the whole process. Austenitizing is hardening, and tempering is drawing back the hardness so the steel is less brittle. Annealing is the process where hardened steel is returned to the pre heat treated state. Leaf springs are heat treated, but are tempered to a less brittle state than a file or a drill bit. Different steels with different alloys have different structures and properties. Modern high end springs have about 0.6% carbon, some chromium, and often silicon in them. A file is 1-1.2% carbon, and very little other alloying. There is a lot to explain with all this, so this is as basic as I can get it.
 
Two hour tempers are good for complex high alloy steels and stainless steels, but simpler carbon steels only need one hour temper cycles. Two hours won't hurt, but there is no gain either.

One hour tempers also cut the time in half. In most of our lives, two hours is a lot of time to gain.

As explained by the others, all springs are hardened. If they weren't, they wouldn't spring back. "Spring temper" ranges from Rc 40 to RC55. It is in the 40 to 50 range in most cases. The old machinists rated the tempering as 1/4 hard. 1/2 hard, and full hard. Generally spring are made of a steel with .70 to .90% carbon and low manganese. Other elements, like vanadium, are added to gain finer grain.
 
Back
Top