I've read some threads in here but some were focused on bearing races. I am doing skidder bushings. Only being 1.5" ID, I am inclined to try the welding method? Was wanting to try 2-3 lengthwise beads rather than trying to weld upside down in a circle with 6013. Plan to push the heat up. Figure I might try to weld on a little piece of rebar in there to use as a driver? Or maybe reaching for the torch is a better play but with limited visibility, I am just worried of making a boo boo.
I like to try welding first before cutting as it doesn’t risk the bore there are times when I’m an absolute surgeon with an O/A torch and times when I’m a butcher. One of the more aggravating bearings to extract were large roller bearings in the vibratory drum housing of a Cat padfoot roller. I had cut the bronze cage with an air hammer to get the cage and rollers gone, then had to weld several courses around the inner diameter, basically full coverage of it, making it look like a stringer bead pad from welding school. Then I welded a thick piece of bar to it, welded a nut to that, and used a 20 pound slide hammer to pull the bearing out Worked like a charm.
Just use the torch to heat the bushings instead of cutting them. The purpose of welding them is just to give them a heat cycle. So just heat them up orange with the torch and let them cool and you'll have the same shrinkage result.
This is what I usually do for small bushings and most bearing races. I've found it's usually much quicker, cheaper and no slag to clean up afterwards.
The one thing to remember, when using a torch. If you plan on cutting the bushing or bearing off, you are much better off to not screw around, like hammering on it or heating it or welding on it. If it hasn’t been disturbed, it’s much harder to cut into the shaft or the bore as it will have a layer of corrosion and your flame will not be apt to jump this corrosion or layer and more apt to just wash away, not hurting shaft or bore. I know I just did a **** job explaining what I meant, maybe someone can articulate it a little bit better.
DONE! cranked up the heat with some 6011 rod. Glued in some old nuts in the bores to make them easy to apply the BFH, and we all good.
When you want lots of heat now, such as this situation, set your torch with to much oxygen. Not quite blow the flame out to much, but about half way there.
Pointed preheat flames is an oxidizing flame with the most heat. Neutral flame gas rounded preheat flames. Of course if you have a bigger tip or rosebud you might not need to worry too much about the flame.