I have seen a lot of welds in my life. I've seen them on new products and on repair jobs. The variety of welds I've seen lately is enough to convince me that some people still don't know where not to weld. In this book I've tried to help those of you who will go on welding a long time after I am gone. I've tried to illustrate as clearly as I know how in words and in pictures some of the places that should not be welded.
I 'ye also included some tips that will help you do a better, safer job in places that should be welded. I hope this book will help you be a better welder. The information in it -gathered the hard way over 49 years -has certainly helped me.
How To Remove A Bad Bearing Race Or Cup From A Hole
If the race or cup is bad, it will be discarded as scrap. Take your arc welder and carefully run a bead around the center of the race, keeping it in the center to prevent drifting off to the other surface. After cooling, it will have loosened enough to fallout. The above race was 4 7/16 inches in diameter before it was welded. After it cooled it was 7 thousandths of an inch smaller in diameter.
Replace New Race
An easy way to replace the bad race with a new one is to place the new race in the freezing compartment of a refrigerator and freeze it before inserting it. Handle it with gloves. Occasionally, a race will turn in the hole and wear the hole out too big. If an internal knurling tool is unavailable, ta-ke a center punch and a hammer and make center punch marks all the way around the entire surface that is loose.
The amount of wear or looseness determines how hard you must hit the center punch. When a piece of mild steel is hit hard enough to make an indentation, the surrounding metal swells outwardly.
How To Build Up A Worn Shaft
First, turn the worn part off in a lathe. Then, preheat it with a torch to about 250°. Have the shaft in a set of rollers so you can turn it from side to side. Weld a bead on the top side. Turn the shaft a half-turn so the new bead is on the bottom.
Then weld a bead on the new top side exactly opposite the first bead. Turn the top of the shaft slightly toward you to make the side of your second bead level. (See Figure 2) Then run another bead overlapping to the center of the second bead. Turn the shaft back over to the first bead and run another bead overlapping the center of the first bead.
You don't need to knock the flux off. After the second and third beads, turn the shaft after each bead to the other side. On the last two beads, weave the rod from side to side to overlap the first and last beads on that side. Fig. 4 shows a built-up shaft. It is hard to believe how much tension is on these welds. They are actually squeezing so hard that the shaft adjoining the welds is compressed to a smaller diameter.
I never gave it a thought until I had a shaft break off at the end of the welds. Therefore, you should always stress relieve the welds. As soon as you finish welding, take your acetylene torch and heat the welds to a red heat. Turn the shaft and heat evenly. Hold the heat on it and give it time to get red to the center of the shaft.
To prove a point, I turned the welds down on a lathe, to the original size, freely slipped the bearing race on to the other end of the shaft, stress relieved the end that was welded, and let it cool. When it was co~d, it was 3 thousandths larger in diameter than it was before I stress relieved it. The bearing race would not come off. I pressed it part of the way off. You can see where I stopped. Then pressed it back on.
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