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

[stoneaxe]

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.

 

[miro]

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

 

[GregSY]

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.

 

[sfriedberg]

The technique has been widely used on connecting rods, where it's simply called "fracture split".

 

[Rob F.]

Joe Michaels mentions the broken cast iron in this thread:

Large Vertical Lathe

THis pic came in on one of my feeds today , you folks may or may not have seen it animal

www.practicalmachinist.com

Post 20?

 

[stoneaxe]

"Fracture joint"- thank you, All.
Rob, that is one amazing thread !

 

[ratbldr427]

Most spherical bearings have a fractured outer race .

 

[stoneaxe]

Most spherical bearings have a fractured outer race .

As in roller or ball type? The fit must be astoundingly good to keep it from wearing!

 

[ratbldr427]

As in roller or ball type? The fit must be astoundingly good to keep it from wearing!

The ball type. How do you think they get the ball in? Roller bearings in the ball type? Same except they can have an outer race in the ball.