What's new
What's new

Axle for my 1910 Mitchell

99Panhard

Stainless
Joined
Feb 22, 2006
Location
Smithfield, Rhode Island
I have to make an axle for the 1910 Mitchell I've been working on for close to ten years. It's 1-3/8" in diameter, about 30 inches long with squared ends. PM Heldt's engineering manual (1912 Edition) states they were made from "30 point carbon steel", "45 point carbon steel", "30 point carbon, 3-1/2% nickel steel", "vanadium steel" or "chrome nickel steel" and that heat treating was required. My question is, what would be an appropriate modern material to replace one of these adding the proviso that I'm doing all this work on what are essentially antique machines with HSS tooling. Of course carbide hadn't been invented in 1910 and HSS was nowhere near as common as it would be 20 years later. It's a full floating rear axle and I have one of the two axles...I'm missing 1 axle and the drive shaft which must have been similar as it runs inside a torque tube.

The MItchell company cut about every corner they could so I'm guessing they used the cheapest materials they could get away with. Nevertheless, the axle I have is in very good condition. Still, I don't relish copying lower quality work so if it is feasible I may make both.
 
Joined
Apr 14, 2018
Location
Totalitarian Ruling Capital, EastAsia
I have to make an axle for the 1910 Mitchell I've been working on for close to ten years. It's 1-3/8" in diameter, about 30 inches long with squared ends.

4340 heat treated to a little over 40, say 42-ish ? ... easy to get and heat treat, works for a UOP Shadow, should hold up to a 1910 mitchell :D

(4142 should be fine too but that diameter is a tad big for a full quench so what the heck, go for the gusto)

Make sure they drop the shafts in endwise or you'll play heck straightening them.
 

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
I have to make an axle for the 1910 Mitchell I've been working on for close to ten years. It's 1-3/8" in diameter, about 30 inches long with squared ends. PM Heldt's engineering manual (1912 Edition) states they were made from "30 point carbon steel", "45 point carbon steel", "30 point carbon, 3-1/2% nickel steel", "vanadium steel" or "chrome nickel steel" and that heat treating was required. My question is, what would be an appropriate modern material to replace one of these adding the proviso that I'm doing all this work on what are essentially antique machines with HSS tooling. Of course carbide hadn't been invented in 1910 and HSS was nowhere near as common as it would be 20 years later. It's a full floating rear axle and I have one of the two axles...I'm missing 1 axle and the drive shaft which must have been similar as it runs inside a torque tube.

The MItchell company cut about every corner they could so I'm guessing they used the cheapest materials they could get away with. Nevertheless, the axle I have is in very good condition. Still, I don't relish copying lower quality work so if it is feasible I may make both.
Have a early thirties Packard super eight rear axle if you want it Joe. You would have to struggle with anneal and then later heat treat, so I doubt it is worth the shipping cost. If you want something to purchase locally - I'd go with 4140 heat treat which is readily machinable as a tough but not very hard condition. I'd suggest NOT acquiring stock in the annealed state.

Here is the data on 4142 from the EMJ catalog
 

Attachments

  • 4142.jpg
    4142.jpg
    311.4 KB · Views: 3
Last edited:

JST

Diamond
Joined
Jun 16, 2001
Location
St Louis
That "squared end" may hold a clue.

Mostly they would be splined, and something like 4140PH would work, because of the large shear area and many surfaces in contact. The hardness would not be too important.

The squared ends would want to fit closely. If they have much slop, they will likely beat themselves round in their sockets. So it may be necessary to harden the ends on the basis of wear.

In that case, a plain carbon steel may be best, hardened on the ends, but not hardened deeply, so that a tough core and wear resistant end is developed. The middle section of the shaft may not need much hardening, so some "creative quenching" might be good.

The 4140PH is tough, but might not resist the beating it might get on the squared ends. It's anywhere from RC25 to RC35 or so, depending.
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
Squares were very common in machines once.....I have a 20 ton crawler crane,and there is not one single spline in the machine......all squared shafts......i agree with the 4140 PH camp ......quite suitable for an axle .........used to use this material for making unobtainable axles for big mobile cranes .......massive loads.....wasnt as good as the original parts,but quite servicable. .
 

99Panhard

Stainless
Joined
Feb 22, 2006
Location
Smithfield, Rhode Island
It looks as if 4140 has the most votes.
John, when you say the "not annealed" state, does that mean it's hard? Would it have to be heat treated afterward? I confess to having almost no experience with modern machining issues. Aside from the help I've gotten on this forum I'm completely self-taught so stuff that may be obvious to most of you is largely greek to me.

Here's the rear axle housing up on the mill table. I'm fitting a drain plug since the Mitchell company didn't see fit to do that. Also, the axle I have showing the squared end. The piece attached is an oil seal made.

IMG_6425.JPG.cb2365b50e75b4c6a5607b748ae08bd9.JPG

IMG_6464.JPG.aec89c0ebcd14b64c949eabab262b653.JPG

I've never tested the squared end to see how hard it is but will do so. It's 1" square and fits into "spider" that, in turn, is fitted into the rear hub. That piece is clearly not hardened and looks like a malleable iron forging.
 

99Panhard

Stainless
Joined
Feb 22, 2006
Location
Smithfield, Rhode Island
Which would be entirely consistent with many other parts on the car. I've completely rejected the popular notion of making it exactly as the factory did. If the factory did a mediocre job I'm not going to copy it slavishly. That seal is an improvement on the original which was clearly inadequate...to the point where they added drain plugs on the underside of the axle tubes to let the oil out that collected there.
 
Last edited:
Joined
Apr 14, 2018
Location
Totalitarian Ruling Capital, EastAsia
Actually ,1&3/8 " is a very large dia for a car axle in a full floating drive setup,and indicates to me the original axle was made of cheap low carbon steel.

The part I'd be concerned about is the hardness of the square, for wear resistance. But it probably has four horsepower and will see twelve hours a year driving, so most likely doesn't matter.

Moonlight's idea of 8620 carburized might actually be the best, just for the square drive but you can get too carried away worrying about this stuff.
 

99Panhard

Stainless
Joined
Feb 22, 2006
Location
Smithfield, Rhode Island
Actually, it was rated at 35 HP although the formula for figuring that is very different from what is used today. For instance...the Silver Ghost RR was rated at 40/50 HP. An 80 or 90 HP car in 1910 would be enormous. It will probably develop close to 50 HP when I'm done at a maximum RPM of 2000. As to use...if I live long enough to finish this I'll be driving it a lot...in fact, my secret goal is to take it on the Peking to Paris ralley.

This will never be a "show car" carried around on a trailer. I don't own a trailer and don't particularly enjoy car shows. I regard the project as a challenge to produce the best mid-size Edwardian car that I can.
 

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
It looks as if 4140 has the most votes.
John, when you say the "not annealed" state, does that mean it's hard? Would it have to be heat treated afterward? I confess to having almost no experience with modern machining issues. Aside from the help I've gotten on this forum I'm completely self-taught so stuff that may be obvious to most of you is largely greek to me.

Here's the rear axle housing up on the mill table. I'm fitting a drain plug since the Mitchell company didn't see fit to do that. Also, the axle I have showing the squared end. The piece attached is an oil seal made.

View attachment 380273

View attachment 380274

I've never tested the squared end to see how hard it is but will do so. It's 1" square and fits into "spider" that, in turn, is fitted into the rear hub. That piece is clearly not hardened and looks like a malleable iron forging.
Joe wrote "not annealed" state, does that mean it's hard?"
There are degrees of "hardness" depending on both "draw" temperature and "tempering" temperature. There is a hint of this on right hand portions of the EMJ (Earle M. Jogensen) attachment. The BRINELL is the hardness resulting (which of course changes with depth). Brinell is another way to check hardness along with Rockwell. Annealed is as "soft" as it gets with thermal methods
 
Joined
Apr 14, 2018
Location
Totalitarian Ruling Capital, EastAsia
...in fact, my secret goal is to take it on the Peking to Paris rally.

I'd be callng Moonlight up to beg for a couple chunks of that 8620 then. Machines easy, heat treats nice, and you can get a good Rc 61 case on it however deep you want with a ductile core.

And then maybe make a couple of the mating parts for spares.

Or if replacement is easier, make them Rc61 and the axles softer, and carry a spare axle or two.

You don't want to be in the middle of nowhere without axles. Even tribal herdsmen don't like dragging 1910 Mitchells :D
 








 
Top