Cast welding - failure.....

[Kojack]

I'm not familiar with the Scout hollow axle but I'm guessing it broke at an undercut at the end of the thread. I have a Chief axle that broke like that. Indian did a couple of things with heat treating that are kind of suspect and this is probably one of them. More than likely they just made these parts a little too hard. On the other hand, it's lasted over 50 years and that ain't bad. Brazing or welding is probably OK since you have the support of the inner axle but it can also affect the heat treatment and if done improperly it will break again. Keep an eye out for another one. You also mentioned heating and quenching a steel rod. The only way to know how hard it is is with a Rockwell tester. We tried this at the shop I worked in and found that the average steel isn't affected too much by this method. There's not enough carbon in it. You may have picked up enough carbon out of the oil to case harden it a little but that won't be very deep. Here's a pretty good article on home shop heat treating. http://asuwlink.uwyo.edu/~metal/heat.html
The drill rod they mention in the article will get VERY hard, over 60Rc is possible. It will also be very brittle so it needs to be tempered back. With heat treating, you're always trying to find the happy medium between the hardness you need and the brittleness you can stand.

[AdminGuy]

Thanks man. Your right. I was on the road and had to get my rear wheel off. The main was bent and I drifted it out. This caused the break or maybe crack at the time- I'm pretty sure. Hey, I'm honest.

So my fault -and now I must fix it. I'll put some miles on the newly heat treated main axel first and see how it holds up.

Working on a Chief is easy compared to a Sport Scout. I was laughing to myself thinking I should take pictures of all the custom wrench configuration required to re torque the head and barrels. Must be about seven or eight. Just for example - The two outer base nuts. You have to lift the valve covers, get your ground down S wrench on from the opposite side. Loop another wrench onto your S wrench and torque it to the point at which the face of the nut flat (which is also special and narrow) is parallel to the tread of the lifter guide. It takes an hour to retorque these two nuts. It's just crazy. Took me a while to figure out all this stuff on my own. I'd love to sit around and watch Robin Markey and his dad rebuild a scout engine. Just to see the different tricks that they use.

I did buy the proper IND valve guide cover plyers. A good investment.

Makes me wonder about how many headaches an earily Knuck holds. Still, we do it -because we love it.

I think everyone had problems with warpage and heat treating at the time. Mainly due to the process that was used from what I understand. So yes in fact. A NOS part can be inferior to a repop part in some cases.

[Tom Lovejoy]

I have bent my rear axle a couple times, was told make sure its tight. I ended up making my own out of stresspruff and have never had another bent axle, my brother in law told me about it so I gave it a try. Seems to work good. How tight did you torque your heads? 50lbs? just curoius, on my SS I pulled the threads out of the cylinders had to put solid plugs in the weakest areas and heli coils in the rest. Was a real bummer at the time, I tell you. Probably about 8 years ago, they take 50 lbs now.

[AdminGuy]

I don't think tight is an issue. It's the shock of a rigid.

Stresspruff? Is that how you spell it? I should look into this. Or just put my main axel into the local pile for heat treating at a proper place. Well, I'll see how it holds up.

Ya, 50lbs. I was aforwarned and did a pre-stress test on the bench. Six heilcoils later I was ready to go. Antisieze on the bolts. Sorry to hear of your on bike head bolt failure. Yes indeed - that would **** large. Or as we say around here. "Boy- Your gunna drive me to drink'in with that hotrod Lincoln". Chuck Berry song I think.
We say that to each other when experiencing grief on a machine.

Hate to say this but I'm using roofing copper and spray glue for head gaskets. It's working really well. Good seal, good heat transfer.

[Tom Lovejoy]

Not sure how its spelled, but any metal shop will know what it is. Not all have it though. Dont think its needed, but it has worked good for me.

[bar]

Stressproof has the tensile strength of a grade 5 bolt. Grade 8 and higher are heat treated. It machines nicely and is about as strong as you will get without heat treating. 12L14 on the other hand machines very well but has the strength of warm butter( about a grade 2 bolt).

[Kojack]

I think 1144 is the grade for stressproof. It's good stuff. 4140 (Chrome Moly) in the annealed state also makes a nice strong axle and might be easier to find (Ebay). Careful with any heat treating. You don't want an axle that's too hard. Bending is better than snapping off like a dry twig. Heat treated threads can chip, break and strip off very easily. Most pro heat treaters know how to handle this but it's not really a job for amateurs. I've seen a few Indian clutch hubs with over-hardened threads on the studs.

[Ohio-Rider]

Another option available to ya would be to make your axle from any cheap steel you have laying around and then to send it out to be carburized in the area's that you would like to be hardened.

That would allow you to keep the threads soft while still maintaining the desired hardness of the rest of the shaft. Carburizing is normally applied to a depth of .060 though it can be applied even thicker. One of the plus sides to it is that it cost less than a chunk of high carbon steel would cost ya. Just one more thing to think about.

[exeric]

I agree with Ohio-Rider. Tough is better than hard when it comes to axels. I worked for a company that used a lot of stressproof in drive assemblies. We used it because it was dimensionally consistant in diameter. We found out, however, that it broke under stress (kind of ironic eh!). We never heat treated it so it's quite possible it would be ideal if properly heat treated.

My feelings about choice of steel depends on the application. Bearing surfaces and things that slide together should generally be hard (which often means brittle). Things that shake, vibrate, or hold weight should be tough.

Hollow axels kind of fall in the middle of the hard and soft debate, which means they should be carburized on the outside and left tough and resilient on the inside. Like an M&M.

[AdminGuy]

So, should I use the stressproof and get it heat treated? What's the concensus?

What do the Indian suppliers have? Do they have a 640 rear main axel that will stand up. Heck, I'd buy it.

Like to hear from any of them. Todd, Gary, Mike, Rocky, Ziggy?

[bar]

Stressproof isn't intended to be hardened I think. Probably something like 01 or 4140 that is then hardened and tempered so it is tough but not very hard would be appropriate . Talk to the heat treater or steel supplier and they should be able to guide you. Cyniding or carburizing would also work with the right steel as the case would be very thin as previously mentioned. I am familiar with the concepts but haven't had to actually had to specify the material or tempering for different applications. My local supplier of tool steel has a metalurgist on staff and I would run something like this past him if I was going to make one.

[swall]

Your side stand may be cast malleable iron--that was the case with the one on my '52 Chief. This material is not weldable. The problem is that malleable iron starts out as white cast iron, a very brittle substance and then goes through a long annealing process to make it malleable--not something you can duplicate with a welding procedure. Only fix is to braze it. On my Chief, the stand had broken off about 4" from the foot. I drilled into the remnant, put a pin in and made a mating part out of steel, also pinned, then brazed the whole thing. I am a metallurgical engineer, BTW.

[swall]

Sorry I posted so late on this--tech stuff like this gets lost in the "Parking Lot" clutter, which is why I suggested in the past that we should have a special misc. tech thread. Some of the stuff I read here really scared me--looks like maybe I should write a short metallurgy column and send it to Blancard.

[AdminGuy]

That's interesting. Please do.

I welded it as indicated and it's very strong. Broken side stands are a huge problem in this club. Just from a casual local survey I discovered.

What should I do with my rear main axel? Case hardening 4140 in used motor oil not a good idea?

[swall]

I'll get back to you on you're rear axle--I need to take the time to read the full post. As for your kickstand--I would suggest you cut a small piece from a non functional, non cosmetic area and get a metallographic specimen prepared at a metallurgical lab. Then it can be determined what kind of cast iron it is. If it is gray iron, you have done all you can. If it is malleable iron, your weld zone will be brittle and you should cut the weld out and re-do it with a pin and braze repair.