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deliberately broken cast iron collar, to fit on shaft between shoulders- what is the term used used for this?


Mar 2, 2010
pacific northwest
I picked up an old ,very well made Craftsman #5183 5" vise- the lead screw was retained by a cast iron nut with external threads to fit the body casting, apparently so backlash could be taken up. Since the nut was captured by the vise handle boss on one side and a flange on the leadscrew on the other, it was deliberately broken along a cast-in weak spot, after machining was complete, so it would fit around the lead screw and retain thread alignment. I have heard of this, but never actually seen an example till now.
What is the term for this method?

BTW, the vise also had a screw tensioner for the main dovetail nut, to keep it snug. A lot of effort was put into minimizing slop.


Sep 16, 2012
port carling, ontario , canada
It's the same idea that is used on drill chucks.
If you ever take one apart, you'll see that the only way that the chuck can be assembled is that the threaded ring that moves the 3 jaws is cracked in half.
To me , it's a good example of "out of the box" thinking


Jan 1, 2005
Don't know about those application but I used to make lots of 2" solid steel studs, about 48" long, with threads on both ends. But one end had about 2" of thread and the other had 5" with a deep V cut at the 3" mark, down to about 3/4". These studs were stacked with motor stator laminations and then a heavy end plate was put in place and nuts tightened. Then the 3" part was cut off with a saw.The extra length was needed during assembly but was in the way after.