A/C B connecting rods "Rework"

That hardness doesn't surprise me. Had it been much less, that would have surprised me.

I'm going to guess that the lifters are 1040 or something close to that. A shop I used to work at made lots of pins, 1040 can be induction hardened rapidly. I'm sure there are several other steels that can too.

I'd be curious to know the Rockwell numbers if you have them. From what been able to gather, it was fairly common for lifters of the era to be hardened to .030-.060 deep. It would be really interesting if the AC ones were hardened throughout or made out of a harder base material with no post-machining hardening.

My surgery was successful. I have been able to sneak off, and I been doing some stuff in the cellar.  An hour or so here and there is a lot better than sitting around.

We have two seasons here in Maine, Winter and Mud season. We spend Mud season getting ready for winter. I am anxious to get outside and to my 4 Simplicity garden tractors.

While I was recovering, I contacted an old friend and sent out the #8 lifter (tappet) to him. He programs (C.N.C.) computerized machinery for a large machine shop here in Maine. They have a Rockwell hardness tester. I asked him to check the center of the round flat and the body diameter of the lifter. I can rattle off some numbers, but they won't mean very much. The lifters are hardened, but not as hard as a hand file.
After grinding off roughly .030 off in my milling machine and grinding off another .015 or so with a 4 inch angle grinder.  The round flat of the #8 lifter, measured virtually the same, as the lifter diameter or within one point on the Rockwell "C" scale. In reality we don't know what they are made from, but they are hardened throughout.
I think that is the important thing for us all to know. I asked him to toss the lifter out after he was finished with the test.

I finished my camshaft. here.

Steve (in ME)

Thanks

I try to do a little bit every day. Today I am cleaning parts with a brush and some dish liquid in a plastic storage bin. Getting ready to sand blast some parts in the booth. I have to stay away from the milling machine until I have a clear head and can focus on the job at hand. It's for my own good really. Lets say my better half is keeping an eye on me. You know what I mean? It's all good.

I will drop in with my progress when I can.

Steve (inMe)

Good luck..

I would agree with your "heat treated" analysis... I think you are trying to OVER THINK this.. Resurfacing your followers is normally a good idea and works out great.

I'm with you wjohn, I'm not too worried about it ether.

I have done a lot of heat treating and annealing. Whether it was done in a heat treat oven or with a torch and a temperature stick. I'm sure that most of you know if you take a hand file to a spot that won't be damaged and if the file slides off of the part without a scratch, chances are it's hard.

The point that I want to make is that "if" the lifters were case hardened, due to the Kasinite powder that the parts are "soaked" in, while they are heated, once cooled, you will see in the places that were not finish ground, a spotted finish from where the carbon has flaked off from being cooled quickly in the water bath.

I would bet that the lifters are made from oil hard tool steel, no doubt grade "O1", that has been in use since 1905. They were no doubt heated with an induction coil, and dropped into an oil bath and hardened throughout. Take it or leave it, but in my honest opinion, any other way is really not an economical way to produce hundreds of lifters.

As far as going off topic. I really wasn't clear about the proper website etiquette.

Not a joke. If I was supposed to start another post, I didn't know. I have more pictures to add. Someone please advise.

Thanks

Steve (inME)

 

I doubt if you will have trouble with running out of adjustment.

FWIW, pretty sure AGCO still sells new ones, not that expensive as I remember. having said that, the ones I bought for a 45 project were pretty rough on the bottom so I stayed with the used ones. They could probably be lapped to make them smoother. Maybe wouldn't have hurt anything and I was just anal about it.

If you go back to page 3, you will see a post from wjohn. There is a link there to another post. In that other post it says, 

 

Jacob (WI,ND) wrote: There are a lot of variables, but I'll give you my two cents from my experience.   On my 20-35 rebuild, we originally used the original worn cam, with resurfaced lifters.  That is what people told us we should do, and we didn't know any better, so we did just that. That was NOT the thing to do! After minimal running we pulled the engine side covers to inspect, to find the edges of several of  the lifters chipped up and you can guess where those chips go. Long story short, we SHOULD have had the cam ground as well as the lifters.  The old funny worn cam was putting pressure on the edges of the new lifters and making them fail.  Maybe it was a fluke, but I don't think so. Tore the engine all back down to have the cam ground, and new lifters AGAIN.  Clean out entire engine.  Very frustrating. Take the time and $ and have both reground.  It really doesn't cost that much compared to fixing the carnage when something goes wrong.  Now you know how I know.

In my opinion, the lifters are made from an "oil hard" tool steel.

Don't get confused with the word "oil hard" that's just a process they use to heat treat.

If they were hard faced or "case hardened" his lifters would not have chipped up and broke into pieces.