Merc Steel Crankshaft
 

Some discussion was recently held here on this subject. Since I have never seen one, nor do I believe they exist, I expressed a desire to examine one of them and offered to pay shipping, both ways, for that opportunity. A Fordbarn friend (RandyZ) did much better than that when he took the time and expense upon himself to send me a sample of a crankshaft he was convinced was steel. This is how we learn things!! By taking the time and having enough interest to go the extra mile.

Not content to use my own analysis skills on the sample I contacted some materials testing laboratories asking the size sample they would need and the price to do the work. The nearest local lab, about 4 hours north, here in Georgia, estimated $350. I found a lab in Pennsylvania who did the work for much less than my Georgia friends.

While machining the sample piece, for the lab, I found the crank to be very well heat treated and tough to machine.

Anyway, the bottom line---- The crank was NOT steel as reported by the materials testing laboratory.

My thanks to RandyZ for his efforts and contribution.
JWL

Re: Merc Steel Crankshaft
 

This is how we learn " the facts man, nothing but the facts"
ks

Re: Merc Steel Crankshaft
 

What did the lab determine the crankshaft material to be?

Re: Merc Steel Crankshaft
 

Well done .

R

Re: Merc Steel Crankshaft
 

"cast iron" contains 2.1 - 4 % carbon, "steel" contains no more than 2 %. Any compentent lab can figure this out, as well as any other alloy components.

Re: Merc Steel Crankshaft
 

My guess is that Henry's cast iron was better than most other's steel.

Re: Merc Steel Crankshaft
 

I happen to have an old scrap crank kicking around. Since the crank pin was already 40 under and it was just a 3 3/4" stroke, I decided to cut it up and use the rear flange and main bearing to make a arbor to be able to balance flywheels. I went to face the cut side, in the lathe and noticed that the swarf was coming off in nice ribbons. Cast iron or Nodular iron that I have turned in the past crumbles into little bits. So I kicked myself for destroying one of the mythical steel cranks.
Fast forward 10 years and John put out a request of a material sample to have tested. Turned out that I still had a piece of the crank, so I cut it smaller and shipped him the piece.
John says that it did test out to be nodular iron, but that it seemed to have a very tough heat treating to it. This made the chips come out somewhat stringy.
Interesting also I hit a hard spot right at the oil hole in the first crank journal. I don't know if it was something in the metal or a piece of broken drill bit from when the crank was made. There was no way the Bi-metal bandsaw blade could cut through it. I had to turn it around and cut from the back side. :eek:

Re: Merc Steel Crankshaft
 

The one I posted a couple of week ago, my crank grinder and balance man swore that was a steel crank. He had to drill a few big hole in the counter weight and the metal came out in a long string, not in chips. He has balanced a lot of flathead cranks for me but said this was the first one of this material. Walt

Re: Merc Steel Crankshaft
 

Well, nodular iron is iron. No amount of heat treat will turn it to steel.
The one I had analyzed was SAE 5000 series cast STEEL.
The mystery continues.