TR2/3/3A TR3 hub removal

[TR3driver]

"nothing gets near 400 degrees, although steel won't loose its temper that low anyway."

"420 is not enough to heat treat steel."

"To alter the grain structure, and thus the temper, you must hold the temp above cherry red for several minutes"

"Randall, you are confusing several different processes."

"Oh you got it off the internet...well then it must be true. Shame I wasted 4 years learning this all wrong."

Oh yeah, I see where you agreed with me right down the line.

And all because I said I prefer not to use heat in this particular case, a safety-critical area that is obviously stressed very close to it's fatigue limit, and an unknown (to me anyway) state of hardening, manufacturing method and steel alloy. I never said it was wrong to do so, only that I prefer to be overly cautious in this case, especially when it's my neck sticking up above the body line. And that it can be done without heat.

The problem, if any, is not so much "loose"-ing the temper as it is creating a boundary where the temper changes. Stresses are increased at such boundaries, because the steel on one side flexes more than the steel on the other. Kind of like the old trick of ripping a phone book in half. And all it takes is for the localized stress to increase beyond the fatigue limit, so the local material starts to fatigue when cornering hard. Actual failure will be many thousands of miles or even hundreds of thousands of miles farther on down the line, likely most people will never drive their cars that far or that hard. (At this point, I probably won't either. I haven't even bothered putting the sway bars back on my current TR3 yet.)

One last point, the blue TR4 in the video I linked to above was built by "uncle jack" Drews, who was not a "bozo" in any sense of the word. He was a very well respected, and very successful Triumph racer, and has probably done more to advance the state of Triumph racing than anyone else short of Kas Kastner. I believe his son Tony was driving it at the time, though. Whether that break had anything to do with Jack's use of heat to separate the hubs, I don't know. Very probably not. I don't care to take the chance since I don't have to.

 

[CJD]

OK...I do disagree. The amount of stress does not change because of the type or condition of the material. The amount of stress on the part is calculated by the load and the geometry of the part. As you point out, load is a function of your driving habits. The geometry of our axle is fixed. So the stress on the part is fixed, no matter what we do with the heat hardening. What you are trying to say is we are changing the properties of the material so it is less fatigue resistant at the cyclic stress we are putting it under.

In material engineering the terms are very strictly defined. From the start, I understand what you are trying to say, but the references, temps and terms you are using are not always correct. For example, under the global term of "heat treating", you have specific processes of annealing, hardening, tempering, case hardening, stress relieving, surface hardening...to list the most common. Each of these processes are distinct and different in the way it is accomplished. The terminology is precise. I have not taken the time to list every time above your terminology is off. But, because I am referring to specific definitions, and you are using "common Street references", we are not communicating effectively. I also have been intentionally vague with temperatures, because it is all dependent on the specific material alloy you are dealing with. I don't know what material our axles are made from....does anybody?

But, to all out there...follow Randall's advice and do not heat your critical steel parts until they glow, or you are altering the properties and may be setting yourself up for a breakage....possibly long after you went torch crazy.

 

[CJD]

I thought of an interesting story...

20 years ago I was building a "big small block" Chevy engine. This is the 400 CI small block that has been stroked with a cast iron crank. Cast iron is much weaker than a forged steel crank, and I was building at least 650 HP into it...so the crank needed some treatment to help it live. Cast iron is not heat treatable, but it can be shot peened, which greatly increases fatigue resistance. I was new to Fort Worth, so I started with the local speed shops.

All the local Friday night racers wanted to shot peen with a mixture of shot and sand. They thought the sand was cleaning the cranks, while the shot was...well...shot peening. In reality, the sand was destroying any benefit they were getting from the shot. This was pre-Internet, so I was working the old phone books. I finally realized I was blessed here, as we are home of Bell Helicopter, General Dynamics, and Lockheed. I was able to find a company that does all the mil-spec shot peening for the aircraft industry!

Anyway...the Forman was great, as he was willing to fit my lonely crank into his multi million dollar batches. When I told him about my trials with sand blasting parts in the racing industry, he told me the following story, that I found very interesting...

In the late '70's, the famous Can Am racer Andy Granatelli came to his company. The rules of Can Am allowed no limit on the engines...so Granatelli was snapping rear axles like toothpicks! He brought a dozen axles in and wanted them shot peened. The Forman asked him, "what material are they made of?". Granatelli refused to tell him! Racers are always trying to get an edge on the competition, and he didn't want word getting out about what he was doing to solve the axle issue that everyone was having.

The Forman said he picked up one axle and immediately told Granatelli, "I need to know the material to properly peen them...I know they're titanium...just nod your head and I'll start the treatment.". He said Granatelli was floored and wanted to know who let his secret out! The Forman explained that although titanium was a secret in auto racing, the aviation industry has been using it for over 50 years. It turned out Granatellis big secret in Can Am was merely common knowledge in aviation!

Metallurgy has evolved over thousands of years. It's one of the oldest disciplines we still have, but we frequently find ourselves "rediscovering" the wheel.

 

[TR3driver]

OK...I do disagree. The amount of stress does not change because of the type or condition of the material. The amount of stress on the part is calculated by the load and the geometry of the part.

So you don't believe in, for example, tempering glass to remove internal stresses?

Yes, the terms I use may not be the ones you learned in school. That doesn't mean what I say is wrong. A discontinuity in material properties (like a change from hardened to less hardened) concentrates the stress at that point. The point stress applied to a single crystal of material does in fact go up relative to the stress applied to the part as a whole. Similar to the concept of stress riser, or heat affected zone.

I've seen it done even. Someone annealed just the splined part of an input shaft to make it easier to machine the clutch splines to mate a different clutch. The diameter at the base of the new splines was smaller, so should have been the weakest point, but the shaft broke in service at the transition between annealed and hardened.

What you are trying to say is we are changing the properties of the material so it is less fatigue resistant at the cyclic stress we are putting it under.

Another valid way to look at it.

In material engineering the terms are very strictly defined.

Again, that may be what they taught you in school, but it isn't necessarily true. Much of the work in materials engineering isn't even in English, let alone always use exactly the same terms.

From the start, I understand what you are trying to say, but the references, temps and terms you are using are not always correct. For example, under the global term of "heat treating", you have specific processes of annealing, hardening, tempering, case hardening, stress relieving, surface hardening...to list the most common.

You are the one that started talking about "heat treating", not me. I was referring specifically to tempering and only branched out trying to explain to you which process I was talking about. Heat treating is a very complex topic (as you point out), I am only talking about one method of tempering. And it is tempering that you have insisted cannot be affected at low temperatures. Remember this one?

To alter the grain structure, and thus the temper, you must hold the temp above cherry red for several minutes

If you are going to insist you didn't say these things, you should at least go back and edit your posts. (Although, since I get a copy on my hard drive, I may still quote your original post.)

I also have been intentionally vague with temperatures,

Er, sorry, but "420 is not enough to heat treat steel" is not "vague about temperature".

But, to all out there...follow Randall's advice and do not heat your critical steel parts until they glow, or you are altering the properties and may be setting yourself up for a breakage....possibly long after you went torch crazy.

Please do not put words in my mouth. I never said that.

My procedure is to not heat TR3-4 axles at all. You go right ahead and heat them if you want to, I'll repeat again I never said it was wrong. Only that I don't care to take the chance, however remote, that heating into the tempering range (which again starts far, far below "they glow") (nice specific term there), will affect the temper.

And I think I've beat this horse about enough. You go ahead and insist that you never said what you said and it's all my fault that you didn't understand what I was talking about (or what you were saying). I'm done.

 

[GeneW]

As the designer of the "one's man solution" (see post #4) I feel obligated to defend my honor!! Winters are long and cold in Northern WI hence there is plenty of time to design and manufacture the "7th mechanical wonder of the world" (see post #6).

I'm sure over the years I've bid against many of you on ebay - and won - quite a few (16 at last count) axle assemblies. All of these, and others sent to me, have been disassembled using the "7th mechanical wonder". The key to breaking any taper is to hold the assembled pieces very rigid during the parting process. This tool does just that function. I use no heat and there is no noise when the tapers separate. In fact it is hard to tell exactly when the parting occurs.

When someone sends me an axle assembly the first thing I do is check the hub for flatness. Many are sent pre-bent and I let the owners know before I start any separation. I suspect some of the bent hubs are the result of using a large press or incorrect puller in the past. In my mind any method that results in "people half a mile away coming out to see what exploded" (see post #2) probably was using forces that could bend the flange. It just isn't necessary to use these high forces. A much smaller force - correctly applied - can separate the tapers.

I also wish to thank Randall for maintaining a copy of the puller PDF. I am intrigued by his thumbnail description of the thread on the outside of the hub (post #4). I anticipate that this Winter I might start on the design of the 8th mechanical wonder of the world!!!

 

[2long]

For Lockheed axles which do not have a taper fit (they have a splined interference fit into the hub), is a specialized hub puller like the Churchhill M86 a necessity? Since I cant seem to find one of those for my tool kit, what is the best alternative, or is an ordinary puller ok for the splined fit of the Lockheed?

Dan

 

[TR3driver]

As you probably know, there is an early service note that says "it is necessary" to use 'Churchill tool M 86' for disc wheel hubs, which I believe is the "top hat" style puller.

I've not tried it myself; but I don't see any reason you couldn't try an ordinary screw-type hub puller. Just don't go overboard on the torque. If it comes off, you're good to go. Otherwise, you need something better A reasonable amount of torque isn't going to damage the hub, it just might not take it off.

"Unreasonable" would be where I wound up with my (rough) replica of the Churchill tool : Standing on the end of a 5' length of pipe over a 3/4" drive breaker bar; somewhere over 1000 ftlb of torque!

 

[CJD]

Gene...we would all love to have your puller. Just looking at it, though, that would be at least a $grand to machine and assemble for those of us who have to farm out machine work. I'm afraid the rest of us are left to compromises with available tools, since this job comes up infrequently.

Dan, I have pulled the hubs on 5 of the lockheed axles, and they are much less of an issue than the later taper axles. The forces involved are an order of magnitude lower.

Randall...rrrrooowwwwrrr! I am done responding to you, as you are now just throwing out unrelated and incorrect ramblings on my behalf. I have not, nor will I edit the posts, after I clean up my attrociace spelling within a few minutes of the original posts. What I have written is absolutely accurate, but it is obvious you don't want to accept it.

 

[TR3driver]

Randall...rrrrooowwwwrrr! I am done responding to you, as you are now just throwing out unrelated and incorrect ramblings on my behalf.

LOL!

https://www.livescience.com/48128-internet-trolls-sadistic-personalities.html

 

[mgedit]

Just pulled the hubs on the 56 TR3 with Lockheed axle (https://www.britishcarforum.com/bcf/showthread.php?101360-Replacing-Lockheed-Axle-Seals-56-TR3). I was worried about what to pull with as well. I used a screw type puller that had been purpose-built for TR6 hubs. It held the hubs tight against itself (and therefore well supported). The hubs come off very easily with this setup. There is limited stress needed as you are pulling along splines, not against a taper. TR6 hubs (which I have done) and I guess later TR3 hubs are a different challenge. Cheers, Mike

 

[CJD]

I love working on the earlier axle. It is easier in every way except for that little axle breakage problem!