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Remove Large gear from shaft - damaged key

I love it! What could go wrong with a big pot of oil with a huge burner underneath. Just be sure to clue in your insurance company on this technique when the policy comes up for renewal. They will love it too.
We did the hot oil on a burner procedure on a regular basis. Some of our production machines had piston rings/seals that were not split and had to be heated to install. They were composition and heating them was the only way to expand them enough. SOP for this type of seal.
 
My only experience with hot oil was back in the mid 1960's at Boy Scout summer camp. We were given a cast iron Dutch oven, a quart of vegetable oil, flour, and some raw chicken to fry. None of us had ever fried chicken before but we had all seen our mothers do it. Remembering the oil bubbling around the chicken when our mothers cooked, we tried to get the oil in that Dutch oven to boil, not knowing it only bubbles when the chicken goes in.

We kept throwing wood on the fire and fanning the flames trying to get that empty pot of oil to bubble. Eventually it burst into flame and splattered out making the fire flair six feet high. I learned a lot that day but I have never again tried to fry chicken.
Where was your scout master the whole time you guys were doing this?
 
Where was your scout master the whole time you guys were doing this?
In scouts you generally camp by "Patrol." A Patrol is 6-10 boys. Our troop was made up of 6-8 Patrols camping 50-80 feet from each other. The adult leaders have their own camp site in the middle of the Patrol camp sites. It's still done that way today, or at least it was 15 years ago when my son was a scout.

The idea behind scouting is teaching leadership, older boys leading and teaching younger ones. A lot of learning is by making mistakes. I learned back then that oil does not need to boil before you put chicken in. 50 years later I still know that.
 
In scouts you generally camp by "Patrol." A Patrol is 6-10 boys. Our troop was made up of 6-8 Patrols camping 50-80 feet from each other. The adult leaders have their own camp site in the middle of the Patrol camp sites. It's still done that way today, or at least it was 15 years ago when my son was a scout.

The idea behind scouting is teaching leadership, older boys leading and teaching younger ones. A lot of learning is by making mistakes. I learned back then that oil does not need to boil before you put chicken in. 50 years later I still know that.
n/m, that was unnecessary.
 
RE a pot of boiling oil. It is safe enough if you turn off the fire and wait a minute for the burner iron bits to cool off below ignition temperature. Then the turkey or bearing causing splashes onto the now cooler burner with no flame.
Bill D
 
One time I was pulling the hub off a Cat 12 grader to fix the brakes .....its just a keyed taper ,but sometimes they are tight ...........anyhoo ,must have pumped the puller up to 60 - 70 tons ,and this idiot working for the contractor stands on the hub and makes silly monkey moves .............so I hit the hub with a sledge ,the hub flew off ,and the idiot did a complete cartwheel............he was very lucky as the hub would be 500lbs easy ,and if it had landed on him,serious damage.
 
The press is very honest if you do it right…good out come; if you do it wrong….very bad out come.

Very bad outcome guaranteed in this case, with a key that's clearly already upset considerable material. Pressing this apart without removing the key would be a Very Bad Thing for the bore of the gear and possibly the rest of it as well. Some here I think don't appreciate the power of a really big press. This may help give some idea:

Quite a few years ago, I was straightening some downcoiler mandrel segments that had been welded for reconditioning. I was using a 500T vertical press. Had to get them straight enough with a straightedge and feelers so that they'd clean up with relatively little stock removal on the OD, that hadn't been welded. This basically consisted of supporting the segment at the ends with 4 blocks, then pressing down on the top of the segment while monitoring how far down the segment traveled with a dial indicator on top, and how far it sprung back. Keep pressing a little at a time until down travel minus spring back equaled about what the feelers under the straightedge told me was necessary.

There were 4 segments total, I had straightened one or two with little fanfare or difficulty, then break time came. Went and had lunch then came back out to the press. Proceeded to get started straightening the next segment. On the next press after break, watching the dial indicator, I saw it go down as usual and then the dial decelerated what seemed ever so slightly more than usual and the descent slowed a tiny bit. Not sure why at the time, I added a little more pressure on with the lever. Went down the same amount as the others and checked. Still needed a little more, so I gave it another press down, a little further this time.

Straightedge said all good, so I went and got the crane to remove the segment. After the segment came up, I saw two 4" cubes of steel some joker had slipped under the segment in the center, thinking it would have me scratching my head as to why I couldn't get the segment straight. They would have acted like stop blocks, except they couldn't do a thing to stop a 500T press. What had started as 4" tall blocks, were now about 3½" tall blocks, with mushroomed out sides. The press had barely even noticed. The segment did though, and received a nice pair of square indents in the bottom face for its trouble.

Anyway, TLDR: a big press will flat out murder anything that doesn't move when it's pressed. A press that is capable of pressing that apart will almost certainly do bad things to the gear bore and quite possibly the rest of the gear. It will also destroy the gear flange, whether it's closely blocked or not, depending on the galling and how stuck the gear is due to the displacement caused by the rotated key. My advice on this one is: cut it out.
 
I love it! What could go wrong with a big pot of oil with a huge burner underneath. Just be sure to clue in your insurance company on this technique when the policy comes up for renewal. They will love it too.
I’m a bit late to this thread for some reason. Obviously I’ve done my share of warming up for shrink fits etc. It goes with the territory.
Back in the day I was warming up two bearings in a 50 gallon oil drum. We used whale oil back then and we always did it out doors because of the smell. Any time I think about it I can always recall the smell of hot whale oil.

Anyway we were doing this in a little internal yard open to the sky. We had the oil drum set up on two angle irons and the gas burner just sat on the concrete between the irons. We’d had the oil drum going for about 2 hours and I decided that it was time to get the bearings out. So I set off for the door leading to the workshop to get my gauntlets and the stevedores hook to fish out the bearings. I left my labourer, Ted, in charge. He was stood by the drum.
I’d just got to the door when there was an almighty explosion behind me. When I looked around all I could see was a big cloud of oil vapour, out of which staggered Ted minus his glasses. When it all cleared the drum was on its side, the brand new bearings were rolling away into the distance, there was oil all over the place. Bit’s of concrete were falling for quite a while afterwards.
There was also a crater in the concrete about 18” wide by about 5” deep where the gas jet had been.
Luckily for Ted the oil drum fell away from him so nobody was hurt. That was the last straw for the whale oil. We bought a SKF bearing heater after that !

Previously I’d been heating some bearings in the same place using the same method when it started raining. No surprise in Manchester ! The oil drum had a lid with a flange on so we put that on the drum.
When it was time, and it was still pissing down, I said to my apprentice - “ Go and get one of those bearings David “. So my apprentice puts on the gauntlets and sets off. When he gets to the drum he juggles with the lid and then inadvertently tipped all the water that had collected in the lid straight into the hot oil.

You know how people say “ don’t use water to put out a chip pan fire ? “ Well now I know why. A jet of pure flame as big as the oil drum shot up skyward. It must have gone 15 to 20 feet. It was instant, but it was also out in an instant. Just one big blast, like a jet engine.

My apprentice came back looking shocked and with one eye brow missing along with part of his fringe !

Be careful out there guys, Tyrone
 
I’m a bit late to this thread for some reason. Obviously I’ve done my share of warming up for shrink fits etc. It goes with the territory.
Back in the day I was warming up two bearings in a 50 gallon oil drum. We used whale oil back then and we always did it out doors because of the smell. Any time I think about it I can always recall the smell of hot whale oil.

Anyway we were doing this in a little internal yard open to the sky. We had the oil drum set up on two angle irons and the gas burner just sat on the concrete between the irons. We’d had the oil drum going for about 2 hours and I decided that it was time to get the bearings out. So I set off for the door leading to the workshop to get my gauntlets and the stevedores hook to fish out the bearings. I left my labourer, Ted, in charge. He was stood by the drum.
I’d just got to the door when there was an almighty explosion behind me. When I looked around all I could see was a big cloud of oil vapour, out of which staggered Ted minus his glasses. When it all cleared the drum was on its side, the brand new bearings were rolling away into the distance, there was oil all over the place. Bit’s of concrete were falling for quite a while afterwards.
There was also a crater in the concrete about 18” wide by about 5” deep where the gas jet had been.
Luckily for Ted the oil drum fell away from him so nobody was hurt. That was the last straw for the whale oil. We bought a SKF bearing heater after that !

Previously I’d been heating some bearings in the same place using the same method when it started raining. No surprise in Manchester ! The oil drum had a lid with a flange on so we put that on the drum.
When it was time, and it was still pissing down, I said to my apprentice - “ Go and get one of those bearings David “. So my apprentice puts on the gauntlets and sets off. When he gets to the drum he juggles with the lid and then inadvertently tipped all the water that had collected in the lid straight into the hot oil.

You know how people say “ don’t use water to put out a chip pan fire ? “ Well now I know why. A jet of pure flame as big as the oil drum shot up skyward. It must have gone 15 to 20 feet. It was instant, but it was also out in an instant. Just one big blast, like a jet engine.

My apprentice came back looking shocked and with one eye brow missing along with part of his fringe !

Be careful out there guys, Tyrone

Yikes. Shouldn't have been doing that without being under a roof. Steam is bad news.
 
It will also destroy the gear flange, whether it's closely blocked or not, depending on the galling and how stuck the gear is due to the displacement
He asked tonage I answered . In this case it is a hollow shaft and a very stout hub. I would saw off the end of the shaft so I am pushing through a minimum length. The key and bore would need cleanup at best. Looks like a fairly easy one to slide out . Honestly I wouldn’t feel like I was wasting my time throwing that in my little 50 ton.
Press destroying things stories are everywhere because the success story’s don’t sound exciting and don’t film well.
 
He asked tonage I answered . In this case it is a hollow shaft and a very stout hub. I would saw off the end of the shaft so I am pushing through a minimum length. The key and bore would need cleanup at best. Looks like a fairly easy one to slide out . Honestly I wouldn’t feel like I was wasting my time throwing that in my little 50 ton.
Press destroying things stories are everywhere because the success story’s don’t sound exciting and don’t film well.

I don't think your 50 ton would even move it, unless it has very little interference fit and that gall doesn't dig in deeper. But sometimes we get lucky. It's worth a try.
 
Does OP have a vertical band saw with a blade welder? Cut blade, pass thru bore, weld. Make multiple cuts from the bore ID out toward the gear hub, stopping just short of the gear. Three cuts 120 degrees apart, then a fourth only a few degrees from one of the others leaving a skinny slice that can be driven towards the center of the bore without jamming. Once the skinny slice is out the others should pretty much fall out, or if they are galled they can be driven towards the center instead of axially.
 
Thanks for all the input, including the hairy tales of what can go wrong.
I'm waiting on the customer to make a decision, but I think if I was going to do the job the best way forwards to take a bunch of measurements of the old shaft.
Then cut one of the shaft off, as close to the gear as possible; it's in the lathe now, so I'd cut a fairly wide groove leaving 1/8" or so for safety. Finish the cut off the lathe.
Mount on the mill and plunge cut the shaft where the keyway is located. This should take out all the stress from the interference fit, then press the shaft out.
It seems a new gearbox is about $14,000 with a 3 to 4 month lead time.
So personally, I don't this is worth repairing, if he can wait.
New piece of 4140 tube is $500. There's a lot of work in that shaft, including the keyways. New SKF bearings for this shaft off Ebay (old stock) about $600 each. This gearbox has 3 shafts, so a lot more bearings and seals etc as well.
Anyone care to estimate what that shaft would cost to machine ?
There'an internal keyway about 3/4" wide right through the full length (12").
Bob
 
Thanks for all the input, including the hairy tales of what can go wrong.
I'm waiting on the customer to make a decision, but I think if I was going to do the job the best way forwards to take a bunch of measurements of the old shaft.
Then cut one of the shaft off, as close to the gear as possible; it's in the lathe now, so I'd cut a fairly wide groove leaving 1/8" or so for safety. Finish the cut off the lathe.
Mount on the mill and plunge cut the shaft where the keyway is located. This should take out all the stress from the interference fit, then press the shaft out.
It seems a new gearbox is about $14,000 with a 3 to 4 month lead time.
So personally, I don't this is worth repairing, if he can wait.
New piece of 4140 tube is $500. There's a lot of work in that shaft, including the keyways. New SKF bearings for this shaft off Ebay (old stock) about $600 each. This gearbox has 3 shafts, so a lot more bearings and seals etc as well.
Anyone care to estimate what that shaft would cost to machine ?
There'an internal keyway about 3/4" wide right through the full length (12").
Bob

What equipment do you have?
 
Just my opinion, but if it's already in the lathe, just bore it out until its just a thin sleeve like I have mentioned before. No need for extra machines, set-ups or a press. Plus it would already be chucked up to clean up the hub bore if needed. Do it all in one set-up.
 
Just my opinion, but if it's already in the lathe, just bore it out until its just a thin sleeve like I have mentioned before. No need for extra machines, set-ups or a press. Plus it would already be chucked up to clean up the hub bore if needed. Do it all in one set-up.
Not so easy. The shaft sticks out 6" from gear, each side, and is 7" dia. I can't get the gear in the chuck jaws as chuck ID much too small.
Once I've cut one side off much easier to put it on the mill, rather than setting up 4 jaw, removing gap, etc.
 








 
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