ring gear

When I was in high school the shop teacher put a ring gear on a flywheel. He just put the flywheel in the freezer in the cafeteria and the ring in the oven. I don't know what temperature the oven was, but I recall the students were impressed with how lose the ring was when he dropped it on the flywheel. I seem to recall it was for an MG. YMMV Mikek

The flywheel / ring gear is pretty large diameter, so you don't need a whole lot of differential expansion to get good clearance. I would think just a few hundred degrees temperature differential would be plenty. When fitting much smaller spindle bearings of around 5" ID we wrapped them in foil and put them in a toaster oven at 250 for a little while with good results.

I changed a ring gear on a snowblower flywheel recently. I pressed the old one off and installed a better one by heating it up in the nose of a torpedo heater. It just fit. I pulled it out with some vise grips and it dropped right in place. Worked great!

Thanks everybody, I'll heat it to where a spritz of wd40 smokes. I don't know this temp - maybe 400.

Lucky for me its -17 outside so i got a good freezer for the flywheel.

Karl

Yep. My son and I did something similar when we rebuilt the transmission on his car last spring: drum in the freezer overnight, annulus in the oven at about 400 F for an hour, and it slid right on.

Really, that doesn't matter much. It's temperature differential that matters, so -17F only adds 86F to the differential vs. 65F room temp. The heating is what matters, unless you have LN2 handy to get some real negative temps.

I did the ring gear thing once on my truck. I was also worried about the 1 shot nature of the task. Followed directions that came with the ring gear, something like 15 minutes in the oven at 400???? Tried to move it to the flywheel real fast just in case. I thought it would never shrink down enough, seemed like 1/4" clearance, and took a minute or 2 to shrink down to fit. I would not worry if I had to do it again.

CarlBoyd

Dang, didn't get any sympathy for you. This cold snap is just plain awful.

Karl

It's been down to single digits at night here in hot sunny Texas, I'm freezing my butt off too.

Years ago when I was an outside salesman for an auto parts warehouse, I called on a machine shop/store. This was a very old business, owned by a couple of crusty, grouchy old machinists. I stepped out the backdoor, then came back in and told one of them "Hey, do you know you have a fire out here??!!!!" He grinned and said "I did that". He had an old cardboard box, threw in some additional carboard scraps, dropped a ring gear in it and set it on fire. then he went back inside to work on another job. Once the fire burned down, he grabbed the ring gear with some pliers and dropped it on the waiting flywheel

So the short answer to how much heat: not very much

Come on, Karl! We slept in a tent half, at lower temperatures in the Army. :)

So, you've never read Fahrenheit 451?

Yep, when we were young. But you turned into a fragile florida flower. And I wish I'd stayed south longer.

Karl

Here are some pictures of another shrink fit operation.

Steel moves at 6 millionths per degree per inch diameter. You can easily figure how much clearance you will get for a differential in temperature of the two parts. A combination of chilling and heating will do the job. Just make sure you have a stop for the ring gear as it drops on the flywheel. Those tires in the pictures are 84" in diameter and had an interference fit of .040 Inch. The material is 4140 alloy steel.

John

Note a sentenc "The flow of oxygen is cut back to produce a bluish flame which is much hotter". Seems like they got it backwards.

Otherwise it was great.

I only cut the Id of the tires for them because they didn't have their boring mill set up yet. They just fit on my vtl. If you ever get to Scranton PA get the tour of steamtown.

John

Wow. I go to Railway museum in Union, IL, every year, with kids.

Once I bought a welder and a compressor from that museum. Still have a huge 8/4 cable from the welder.

I have a picture that my wife took of me standing next to the Union Pacific 4012, but that was when it was in Bellows Falls, VT. I'll have to visit it when I pass thru PA on the way back to New England. I didn't know that there was a railroad museum nearby in Union, IL. I'll have to check that out too!

Karl, it is 59 degrees in the house right now. I'm in a tee shirt & shorts. I went to our Pearl Harbor ceremony the same way, and it was in the 30s. I see people in long winter coats when it's 70 degrees around here. I get tired of people asking, "Aren't you cold?" all the time. :)