heated gears

[drs23]

Am helping a friend do a gear dr. set up on a TC. Went from 88" to 95" with cams and the usual. He'd read here and elsewhere about heating the gears to make them go on more easily. Not being accustomed to electric ranges I turned the knob to the second hash mark of "simmer". Bottom line: it got hot pretty quick and the gears turned blue. Time frame I'm guessing to be 2 - 4 minutes. What I'd like to know from some of the metallurgists out there is "HOW" critical is this as a problem. Since I'm doing this as a favor and it's not an income producing job, I hate to pony up the if there's not really a safety issue. I'm going to take them out of the bike they're in and replace them with the inner gears out of my own bike since it's down right now anyway. Worse case scenario, I'd just have to wait and save up the pennies to purchase another inner gear set to get my ride back up if it's deemed that I'd be making a time bomb Any empirical evidence that this is the case.

Thanks much,

Dale

[fattyboy3]

a " little "blue-ing is alright, put the gear in the oven, heat to 100 C over ambient then quickly install. generaly speaking though blueing is not good. 
ps not a metalurgist, but I  do this regulary.......also I do stay at holiday inn exprerss...regularly

[Tsani]

If you can, throw a pic up.

[Richard Till]

 put the part that the bearing is to be installed in the freezer for a while. heat the bearing mostly in the middle but not to the point of blueing. i`ve seen that trick done since 1967 when i was in high school. i was in shop class and we were installing a sleeve in a school bus engine block. the instructor had me carry the sleeve to the lunchroom and ask the lunchroom worker if she would put the boxed sleeve in the freezer. we bored the cylinders that day and installed the frozen sleeve the next. the next day we bored the sleeved cylinder. this might just work for you. good luck......

[HIPPO]

Hard to say. Since you mention "simmer" and a few minutes it may well be that they turned blue from having either oil or cosmoline on them. It takes a lot of heat to discolor them if they have been washed.

[drs23]

Here is a photo as requested. As you can see, they look pretty blue to me.

Hippo, as I wasn't "hands on" every minute, I'm not thinking he washed them. I did go get another gear and put a file on it and it scratched fairly easily. More so than I would have thought and these do about the same. Would you all suggest removing and a thourough cleaning? or just let them go? or coming out of my pocket to replace?

Thanks again,

Dale

[Panzer]

DRS,
I don't want to hijack anyones theory here, not intended.....but......
Just a thought.......why don't you call Andrew's themselves and ask them if they would look at those pixs that you have, along with the story.
Send them the pixs and see what they say.......right from the horses mouth.
I don't think there was enough heat in what you said to alter the tensile strength, but I'm not a metallurgist either.
Another thought.........send it back to them and let them check the gears........beats buying another set, cost wise.
Just a couple of avenues for you to try.

Panzer

[truck]

Just an observation but that shade of blue doesn't look like heat treatment blue.

[Dennis The Menace]

Cool blue color regardless. :-)   Just like the stock clutch plates I replaced on my 07 RG 2 months ago.

In all seriousness, is it normal procedure to use heat to press the bearings on, or does it usually require like a 20-ton press or something?  Sorry for the dumazz question, but I truly dont know aboout this topic.

menace

[Ultrashovel]

I don't know what Andrews might say but it looks as if you have taken the heat treating out of your gears. Let us know what they say.

[Norton Commando]

I can't imagine that 2-4 minutes at "simmer" on an electric stove would be hot enough or long enough to anneal (soften) those gears. The blue color must be a reaction with the oil or some other coating on the gears. In other words, I think the "blue" tinge is making things look worse than they are. For any annealing to take place on hard, alloy steel I'm guessing the temperature would have to be closer to 900 degrees F and held there for way more than 4 minutes.

[Tsani]

Exactly how did you heat them? In a pan or direct contact? Direct contact on an electric burner coil, yah, you could have an issue. As for putting on bearings, we used to heat the bearing, not the shafts. The shafts we would chill. Take them to a machine shop and have them check them for hardness.

[Panzer]

I'm with Norton on that one.
A brinell test is in order.
But like Dennis said, they are a cool blue.
A suggestion for HD, "heat treat blue", maybe in 2010? 

[drs23]

Have forwarded a pic to Gary Wallace in tech support @ andrews per Panzer's suggestion and will report back what he says and will follow his recommendation. (I see fifties flying  ) Oh well...

Think I could get a capped buy-out of "Electric (Range) Blue" from the MOCO since the color is a hit??

Thanks for all the feedback.

Dale

[triumphbruce]

we heat treat and Annalee plate steel .063 to .090 it has to sit in the oven
at high temps for a lot longer than that.times and temp are different
for thickness and hardness.you have only burnt the color on
from the oil or preservative on the metal  

[Billy]

I believe Tsani has given you the best advice. Take them and a known good gear to a machine shop and have them hardness tested and compare them.

[Panzer]

Right on Billy, I'll second that.
Keep the fifties in your pocket, or you could send a few to me.
I take plastic too. 
Good luck bro.

[ccrane2299]

Even if it was overheated, if it was allowed to cool naturally, it should not have changed the hardness?

[highlander]

I've been a diesel Mechanic and Coast Guard naval engineer since 1971, and after I retired I worked in a tool room at a metal stamping company in Wisconsin. That blue is typically what I saw coming from our heat treating over for the tool and die makers. It' usually comes from high carbon steel. I'd be more worried about those gears having become more brittle than anything else. No doubt you changed the internal structure of the parts. I for one wouldn't use them.

As someone else said though, KEWL Blue!

[highlander]

I just did some checking, the link below talks about heat treating for the amiture. below that is an excerpt from that article. Your blue is somewhere just before the 520 deg F. They got plenty hot, not sure about damage.

http://asuwlink.uwyo.edu/~metal/heat.html

Accurately measuring the tempering temperature is important. A nice, expensive thermostatically-controlled oven is great. Or, some special compounds can be applied that melt or change color at the right temp, such as Tempilstik and Tempilaq. If the steel is clean to start with, then you may notice that it goes through certain color changes as it heats up, with understandably vague descriptions such as "light straw" indicating about 440 degrees F, and purple=520. These colors are not incandescence colors, but are viewed in normal room light. The colors are due to types of surface oxidation that are temperature dependent.

[04glide]

Just my 2 cents. I don't think you got them anywhere near hot enough to hurt them. What I think you are seeing is the oil that was on them turned them blue as it burned off. Can you sand the blue off of them? I think you just stained them.

[ridinflyin]

Did something of the same to mine, in the gas oven at broil for about 10min took them out and were blue also   wrote here  and got the same answers  put them in  and 5000 mi later seem to be holding up fine  I believe they are coated from the factory to prevent rust cause the color is a silver and not a fresh milled  cut finish other wise they would have been wrapped in that yellow wax paper and have grease  or oil  for stocking 

[drs23]

Got a call back from Gary Wallace with Andrews. He too says they reached temps in excess of 540d. I just don't see this on SIMMER! He went on to say that they see that on Sporty gears that are not fitted correctly and that within just several hundred miles they will "shred" and this fella's Dad will have metal throughout his brandy new motor. Am going to pull them later today and attempt cleaning them and see if the color change is cosmoline/oil or if they indeed got way hotter than I believe they did. Worse case I've got replacements coming as I can't take a chance with it. I was tempted to just exchange them with mine but hell, if they shred, there goes my motor and it's got enough problems of it's own .

Thanks to all,

Dale

[02roadcling]

Dale,
I read all thru and never saw what you cooked them in. Was it in a pan of water (simmer), or directly on the actual burner? If it was actually on the burner then it might of got too hot. Other than that I wouldn't sweat it.

cling

[Billy]

Am going to pull them later today and attempt cleaning them and see if the color change is cosmoline/oil or if they indeed got way hotter than I believe they did.

Cleaning them is not going to show you this, whatever discolored them will come off with light sanding as it is surface oxidation.

Heat treating of any kind will not change the color of the metal through the section.

Hardness testing is the only way to determine if you changed the temper.

I'm a retired Toolmaker and closet metallurgist.

[drs23]

02,

Didn't have them in anything, just lying on the porcelain burner, two hash marks from the off position.

Billy, thanks for the response. Didn't get a chance to pull them yet as I've been swamped but will try to get to them this PM. Would bead blasting them return them to their original color and pardon this question but where would one go to have the hardness tested?

Thanks,

Dale

[Tsani]

Take em to a good machine shop and they should be able to test them. Since you had them directly on the burner, unfortunately there is a good chance they where overheated. I don't know the hardness of the Andrews gears normally, maybe someone else can answer that. But a good machine shop should be able to tell you if they are useable. Good luck and let us know how this all goes.

[Jeffd]

get one of them ir temp guns and put the burner back on simmer and see how hot it gets.

[Billy]

Would bead blasting them return them to their original color and pardon this question but where would one go to have the hardness tested?

Thanks,

Dale

Dale, yes bead blasting will do it. As Tsani says a good machine shop will be able to hardness test them. Maybe call ahead to make sure they can do it.

Good luck.

[darrelbarrows]

if you have a local college and they offer any physics or shop classes alot of them have a rockwell tester and would probley be more than willing to test it for you. A good project for a student...