Does anyone know what type of steel was used for the original Model T rear axle shafts?
The reason I'm asking is that I'm building a planishing hammer and using an air chisel for the power source. I need a holder to fit into the air chisel to accept the upper die. Last night I machined one up from a piece of Model T axle shaft to see how everything would work out. Once I was satisfied with the design I was going to make the "real" one out of tool steel. I think it needs to be hardened as the ram in the chisel will be pounding against the end of this piece and if not hardened it will probably mushroom the end.
I'm wondering if it would be possible to just harden the piece I made from the axle. I have some Cherry Red which is used for case hardening - wondering if that would work. Or, should I just stick with the original plan and make it out of tool steel?
Case hardening will not prevent the inner steel from mushrooming and fracturing the hardened exterior
It depends on when your Ford axle shaft was produced. In this long discussion Glen Chaffin shares the changes on the Ford drawing for the axle shafts: http://www.mtfca.com/discus/messages/80257/100062.html?1249952529
2/32/11 Material AA Steel
Heat Treat C32-C34
5/3/17 Heat treat C29-C35
10/22/20 Heat Treat C32-C35
8/13/21 Material AAA Steel
Heat Treat C32-C36.6
1/30/22 Name Ford to be stamped on the rough, unmachined part of the axle instead of in the keyway.
8/20/23 Material EE Steel
10/13/23 C32-C36.6 on the Bearings
C45-C49.6 on the Center of axle
8/29/24 Name Ford to be stamped in the keyway instead of on the rough, unmachined part of the axle.
Here is a discussion on what was in Ford's AA, AAA and EE steels:
Ford steel is generally good steel. I think you can harden it (not as much as tool steel though) and have a go at it
The worst case scenario is you'll have to make the part again, I suppose.
Ok, Leonard has a point. The hardening on axle shafts was mainly to handle wear, not to handle shock loads like from an air chisel.
Both of my Grand Daddy's raised me, and both were Country Blacksmiths. My Paternal Grand Daddy made a living a time or two Blacksmithing, neither had ever heard of an electric welder or bottled gasses, it was all flame weld or not. Both kept a pile of Model T axles out back to make Spurs out of. They would cut off a chunk and split it to make the yoke, heel band, or shank, as we called it. Lot of work went into this, as you can imagine. Back when I was messing with such things, the old steel that you picked up and used for the most part had a very distinctive ring to it, I am not a Metallurgist by any means, but that ring meant good iron to me.
Good point about the case hardening.
Roger - thanks for the info and the link.
I guess I'll see how this works, and if needed I'll remake it in tool steel and have it hardened.