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BABBITING A HAMMER
PART I OF A 2-PART ARTICLE
About two years into my apprenticeship, I knew that I wanted to eventually establish my own shop. I found the opportunity to buy some equipment, and bought several anvils and two triphammers. One of them, a Williams and White 150 pounder, which is similar in design to a Champion actuated by leaf spring loaded hammerheads, had very sloppy main bearings. The main shaft that turned the flywheel to which the tup was attached wobbled as I turned the hammer. Alas, the babbit bushings in the main bearings were shot.
When I discovered this problem, through a Russian interpreter in the shop where I was serving the apprenticeship, I told the master for whom I was working about the bad bushings in the hammer that I had just purchased. He told me that during the weekend, he would help me fix my hammer. He advised me to purchase a bar of babbit and a can of DAP window putty. He also advised me to bring a 3/8 inch electric drill and some baling wire. Both of us lived and worked in Philadelphia, and he accompanied me to my fledgling shop in Montrose, PA, 200 miles away.
I am going to describe how he repaired my bushings on the hammer. First of all, he removed the flywheel from which the hammer head and springs were hanging from the main shaft. Then he removed both the front and rear bearing caps from the shaft, so that the shaft wasn’t attached to anything and was free and clear of the hammer. The first cap was in the front of the hammer, near the tup. The other cap was in the back of the hammer. In the second installment of this article, I will describe how we poured babbit bushings in the caps. This installment will describe how we poured babbit in the main bearing parts of the hammer intrinsic to the hammer itself, front and back.
The first thing he did was to scrape out old remnants of babbit from the areas in the bearings where the main shaft turned. Then he took an electric drill, with a drill bit at least ¼ inch in diameter, and drilled two small holes about 3/8 inch deep{no more than that} into the cast iron where you are about to pour the babbit. The reason for these two holes is that when the molten babbit goes into these two small holes, it keeps the babbit from falling out or moving around after it cools. He drilled these two tiny holes 3/8 inch deep in both the front and back bearing housings. The next step, which should be done very carefully and precisely, is to hang the main shaft, using a frame consisting of 2x4’s with baling wire, over the front and back bearings, making certain that the shaft is hanging CENTERED in the housing, exactly in the same position as the shaft was before you removed it. Exactly half the shaft should be hanging inside the housings, too deep into the housings, or too shallow will result in a lopsided bushing. Because the main shaft is hanging by baling wire from a two by four frame, one can easily adjust the positioning of the shaft inside the bearing housings. Looking back to front on your hammer, there should be a nice, even gap between the shaft and the housing, front and back.
For the next step, pry open your can of DAP window putty. On the front bearing housing, fill in the gap in the front and the back of the front bearing between the hanging shaft and the housing with window putty. Window putty is an excellent damming material for containing molten babbit. Then, using a good heat source{we used my coal forge} heat up a piece of cold babbit in an iron ladle. When the babbit turns liquid, pour it from the side, into the gap between the shaft and the bearing housing, in one continuous pour, filling the open area between the shaft and the housing. This same process is to be repeated, using the DAP window putty on the rear bearing.
When the babbit cools, remove the DAP window putty dams. If there is excess babbit that ended up on the flat spots where the bearing caps bolt down to the bearing housing, scrape that excess off with a file on both bearings. If you did this process correctly, the bottom halves of these bearings should be evenly babbited around the main shaft, front bearing and back.
The final step in babbiting the bottom halves of the bearings are cutting grooves into the babbit to retain oil. This is done with a thin, fine chisel. When you eventually pour the top halves of the babbit into the two bearing caps, and put the hammer back together, those grooves cut into the babbit with that fine chisel allows the bearings to hold oil in the chisel cuts for awhile, prolonging the effects of lubrication. In the next installment, I will describe how we poured babbit bushings into the bearing caps.
PART I OF A 2-PART ARTICLE
About two years into my apprenticeship, I knew that I wanted to eventually establish my own shop. I found the opportunity to buy some equipment, and bought several anvils and two triphammers. One of them, a Williams and White 150 pounder, which is similar in design to a Champion actuated by leaf spring loaded hammerheads, had very sloppy main bearings. The main shaft that turned the flywheel to which the tup was attached wobbled as I turned the hammer. Alas, the babbit bushings in the main bearings were shot.
When I discovered this problem, through a Russian interpreter in the shop where I was serving the apprenticeship, I told the master for whom I was working about the bad bushings in the hammer that I had just purchased. He told me that during the weekend, he would help me fix my hammer. He advised me to purchase a bar of babbit and a can of DAP window putty. He also advised me to bring a 3/8 inch electric drill and some baling wire. Both of us lived and worked in Philadelphia, and he accompanied me to my fledgling shop in Montrose, PA, 200 miles away.
I am going to describe how he repaired my bushings on the hammer. First of all, he removed the flywheel from which the hammer head and springs were hanging from the main shaft. Then he removed both the front and rear bearing caps from the shaft, so that the shaft wasn’t attached to anything and was free and clear of the hammer. The first cap was in the front of the hammer, near the tup. The other cap was in the back of the hammer. In the second installment of this article, I will describe how we poured babbit bushings in the caps. This installment will describe how we poured babbit in the main bearing parts of the hammer intrinsic to the hammer itself, front and back.
The first thing he did was to scrape out old remnants of babbit from the areas in the bearings where the main shaft turned. Then he took an electric drill, with a drill bit at least ¼ inch in diameter, and drilled two small holes about 3/8 inch deep{no more than that} into the cast iron where you are about to pour the babbit. The reason for these two holes is that when the molten babbit goes into these two small holes, it keeps the babbit from falling out or moving around after it cools. He drilled these two tiny holes 3/8 inch deep in both the front and back bearing housings. The next step, which should be done very carefully and precisely, is to hang the main shaft, using a frame consisting of 2x4’s with baling wire, over the front and back bearings, making certain that the shaft is hanging CENTERED in the housing, exactly in the same position as the shaft was before you removed it. Exactly half the shaft should be hanging inside the housings, too deep into the housings, or too shallow will result in a lopsided bushing. Because the main shaft is hanging by baling wire from a two by four frame, one can easily adjust the positioning of the shaft inside the bearing housings. Looking back to front on your hammer, there should be a nice, even gap between the shaft and the housing, front and back.
For the next step, pry open your can of DAP window putty. On the front bearing housing, fill in the gap in the front and the back of the front bearing between the hanging shaft and the housing with window putty. Window putty is an excellent damming material for containing molten babbit. Then, using a good heat source{we used my coal forge} heat up a piece of cold babbit in an iron ladle. When the babbit turns liquid, pour it from the side, into the gap between the shaft and the bearing housing, in one continuous pour, filling the open area between the shaft and the housing. This same process is to be repeated, using the DAP window putty on the rear bearing.
When the babbit cools, remove the DAP window putty dams. If there is excess babbit that ended up on the flat spots where the bearing caps bolt down to the bearing housing, scrape that excess off with a file on both bearings. If you did this process correctly, the bottom halves of these bearings should be evenly babbited around the main shaft, front bearing and back.
The final step in babbiting the bottom halves of the bearings are cutting grooves into the babbit to retain oil. This is done with a thin, fine chisel. When you eventually pour the top halves of the babbit into the two bearing caps, and put the hammer back together, those grooves cut into the babbit with that fine chisel allows the bearings to hold oil in the chisel cuts for awhile, prolonging the effects of lubrication. In the next installment, I will describe how we poured babbit bushings into the bearing caps.
