Joining tubes of different sizes

There is very little basic difference in the procedures for joining tubes of different sizes and for joining tubes of the same size. The main difference lies in the preparation of the end of the larger tube the end of this tube should be drawn down to a spindle and the spindle cut off in the flame. The closed end so produced should be heated locally so that vslien it is blown out the hole produced will be of the same size as the bore of the smaller tube. But it is usually better to... 

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