Metalurgy of a TLT Axle

[RallyRoach]

--Had my bro look over the post, made some changes-- :?

Sorry for the long post, but hopefully there's info here which some of you might find interesting or usefull...

My brother is a Metallurgical Engineer, currently working on his Masters Degree. I broke an axle in my TLT crawler a while back and mentioned it to him. Since he's a Masters student, he has access to all the equipment the school has. His current research involves alot of setting up an experiment, then letting it run for hours, so he has tons of free time. He offered to examine the TLT parts to see if there's anything that can be done to improve durabilty. Here's what he's found out so far:

TLT Axle shaft: (original RockBuster, not MaxClimber)
He had a close look at one of my broken shafts. This one broke in the same spot as always, at the neck-down point on the dog-bone. He first cut the shaft in the middle, polished and mounted it to do some tests. he then did the same at the break point. This involved electron microscope time, and some non-destructive tests.
The steel used is very low-grade, with not much carbon in it. Also, his opinion is that the shafts are not machined on a lathe, but rolled. The grain of the metal at the e-clip slots, around the dog-bone neck and at the splines shows signs of compression which would not be present if it was machined. It also means that these are weak points because where the metal was compresed, its more brittle.
His first thought to make the axle stronger was to heat treat it, but due to the low carbon content, it won't increase strength much. What heat treating might do is take some of the brittleness out of the rolled sections allowing it to bend instead of break (I will update this post after that's done with results). If it works, this is something that most people would be able to do in their oven at homes, as the heat required is around 500 F
The next thought is to try case hardening, using either corbon or nitrogen gas in an oven. I've got some more spares on order with Tower, so the next time the oven is running, we'll run a set through.

TLT Ring and Pinion:
Not too much done here, as I don't have broken one to sacrifice. He has done some preliminary testing on one of my spares, but all he can say without cutting it apart is that it is a non-ferrous pot metal. His guess is that its a mixture of tin, lead, aluminum, and whatever else was available on casting day at the foundry. There is another student doing research on hard nickel plating with metals like this, so the next time he is doing a run, he will try to get a set included. This should increase wear resistance if it works.

And there it is. I've basically tried to rewrite what he told me in common language so everyone can understand, but I don't quite understand all of it myself, so if I've got something wrong, let me know. If anyone has any questions, I will pass them along to my bro. Right now, we can't move forward without some more samples. We need the following parts to make a complete report:

-Ring and Pinion from Rock-Buster kit
-Ring and Pinion from Max Climber kit
-Axles from Max-Climber kit

If anyone has some of these they can send, please PM me. Broken axles, or stripped out ring and pinions is what we need, as the testing left to be done is all destructive. I will update this post as I find out more info (or errors). The only downside of all this is that some of our solutions may not be within the grasp of regular people. Once we know what works, then hopefully we can find DIY ways to accomplish the same things.

[Double J]

That is very interesting to read.
Isn't there after market shafts and ring and pinion available for the TLT. It would be interesting to see the difference in the make up between the stock and the aftermarket parts, to see what type of % of the metals are in the two parts.
I would also like to see how the metals in the TLT compair to like a clod or TXT to see if they are better since they are larger scale or if its the same type of inferior metal.

Another thing to remeber that these are made in china, japan or where ever and the manufactures over seas will allways use less desired metals to achieve a less expensive product. Only way to get them to use a more desirable metal is in months and months of telling them .. NO not this, but This. I tried to get them to use 6061 aluminum for some speaker grills, but they keep sending me their crap aluminum version. And language differences makes it that much more difficult.

[rerock]

If there are aftermarket ones available, I'd sure buy them! I'd like to see a different ring gear set up. Something strong like the pinion, but like a spool with a ring gear on it. Those stock ring gear cases are seem to be just cast pot metal that is alot weaker than thanthe pinion. Some company needs to machine new ones. Different gear ratio combinations would be cool too...

[Wrecker]

Cool post, I def want to hear the results of these test.
btw, right now I'm sitting in the Metalurgy office of the Colorado School of Mines working (work study), I really need to learn how to use all of the awesome stuff they have here so I can do stuff like you guys are doing.

[pro beater]

well , i'm glad i'm not the only one here snap'n off axles , i wouldnt mind see'n one of the Machinists on the site make'n toolsteel or hardened axles , i know i'd have to but like 4 sets

[Mad Scientist]

Interesting post. I always like to see different aspects of Science being used in this hobby.

[chaotic_life]

Thats very interesting, I'm certainly interested in hearing more...
-Blake

[Double J]

So are saying that there isn't any aftermarket parts that you all use for the tlt?

[RallyRoach]

Originally Posted by Double J

So are saying that there isn't any aftermarket parts that you all use for the tlt?

Yes, that's correct. None of the internals of the TLT axles (except bearings of course) have been duplicated by the aftermarket yet. I've seen a few posts with people who have investigated custom machine work, but unless you can do it yourself, its too expensive. I thought I might look at the options available to beef up what we have until a company steps up (HINT HINT).

Titanium everything!!!