My thumb project expanded exponentially. I got into dozens of new bushings & pins to tighten everything up. I've developed a favorite technique for bushing removal. I use any variety of stick weld rod. I can weld three strips longitudinal to the bushing, or just move around rotating the weld deposit. This is about heating the bushing without much heat to the bore. Putting the new bushing in the bore has been difficult! Two men wrestling with it, we ruined a 20 ton hydraulic press. An all day job put 10 bushings in place. I put them in the home freezer with no discernible improvement. Researched it on the internet. Shrinking it to 0 degrees F in the home freezer experts disagree. Most say a straight 12" bar would shrink .0001" from 70 F to 0 F others point out the change in diameter is divided by 3.1416. It seemed too easy. I read canned air sprayed upside down will superchill it. It seemed too easy, but I tried it. IT WORKED! Took 2 minutes to hammer the first bushing into place!
"Canned air"...tell me more, please.
The welding works good for bearing races also. As the weld cools it shrinks the race enough that they may even just fall out. Was skeptical the first time I tried it but it worked and saved me a ton of time trying to grind and split the thing out of a blind bore.
The spray cans of "air" used to dust computers, keyboards and such. Hold upside down and spray the bushing.... the sudden expansion of the propellant causes quite the cooling of the piece..... more than a freezer. Check out some you's tubes videos...... I used the technique on the boom to swing tower bushings...... got them started ok but you don't have much time . I think I took more than two minutes... and probably a bigger hammer than Willie
I researched liquid nitrogen, and dry ice. If memory & internet figures agree, Dry ice (Frozen CO2) is -96 F Liquid nitrogen is -190F. I'm probably wrong about Fahrenheit or Celsius, and certainly wrong about temperature. Nonetheless, home freezer = only a little contraction, dry ice = more, but only a little more. Liquid nitrogen = still not much, but maybe enough. Locally, I can buy dry ice, (20 miles from here) It might be cold enough, but no guarantees. Liquid nitrogen is only available to those able to receive it high pressure. A guy, (I can't seem to get his name) services artificial breeders. He shows up unannounced 3 times a year, refills breeder tanks. If I understand, he puts in enough liquid to freeze until his next visit. I have a farmer willing to gamble, but I'm not willing to risk thousands of dollars of bull semen spoiling. I will NOT take him up on his offer to pour some out.
Liquid nitrogen or dry ice may make them brittle enough to shatter when you hit them? Just speculation, not experience talking.
You can also turn you r134 bottle up side down and do this or really any compressed gas
Poor man liquid nitrogen acetone and dry ice, never tried it myself we had insulated jugs for liquid nitrogen at demo company i worked at and airgas was only a mile away. Mostly used for hyd breaker bushing, genisis main pin on shears and the occasional sandwiche the grumpy old guy left on his tool box
You dont have to hit them .you better be sure you have a way to handle them and get them set in their bores properly cuz you got a second or less after they touch the metal at ambient temp before they expand and stick in place .
From experience with acetone & dry ice. Dry ice will last over night (even days) with some shrinkage in a cooler. The better the cooler, the less shrinkage. A hook to pull part out of bath and leather gloves to handle the part. Have a stop rigged up to position the part in the bore. Sometimes, the bushing just falls through. If it stops in the wrong position, you're stuck when it warms.
When we would drop bushing in NPK hammers with approximately .003" to .005" interference fit, we would aim a torpedo heater or 2 at the housing, we would monitor the temperature with infrared temp gun. At the same time we would have the bushing chilling in the cooler of dry ice. When the housing was 350° we'd pull the bushing and drop her in. Always had a driver and sledge in case it hung up. Never had issues doing it this way. Heating the receiving bore helps so much. Another small help is liberal application of anti seize. It helps the bushing slide, it insulates against heat transfer. Like Hosspuller said, have you a good stop in place. Best of luck.
customer of ours used liquid Nitrogen to install a pin on a loading shovel, They ended up buying a second one as it cracked straight along it's length
The last of the new bushings went in this morning. Me holding a 40 LB piece of 3" steel shaft as a drift, Seth with a 10 LB hammer at full swing. I've had years of practice hitting a moving 5/8" ground rod. He is less precise. I'll admit to being nervous. Canned air shrunk it just enough to make hammering feasible.