For those that have removed/installed an x or y axis nut

R

R Thor

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I am rebuilding a very old Lagun mill. I have a question regarding the x and y axis feed screw nuts. These are the one piece brass nuts with a slot in the middle so that nut can be collapsed slightly by the retaining/adjusting screw to make slight backlash adjustments. Being the machine is so old there is a lot of backlash. I have the yoke that carries those two nuts out of the machine. When I remove and reinstall those nuts into the yoke it is a press or interference fit between the nut and the yoke.

In my mind I think the interference is excessive. I do not believe that the retaining/adjusting screw is capable of collapsing the nut because the nut is so tight in the bore of the yoke. Also the head of that screw is bent over likely from someone overnighting it trying t get the nut to collapse some. I will need to replace it. So my question for those that have removed and installed those nuts is did you find the nut to yoke fit to be a interference, transition or a clearance fit.

I may be splitting the nuts but that is a different subject. For now I am just wanting to know what the design intent is regarding the fit between the nut and yoke. Thanks for reading my post.
 
As I recall, on my BP they where just a slip fit. Mike
 
When I replace screws and nuts or just the nuts, I always install the nuts on the screw before sliding it into the yoke.

Jon
 
Okay I might have been a bit premature with my above post. I removed the nuts once again from the yoke. They did not slide out, I had to press them out. I soaked the yoke in degreaser overnight. I took a piece of fine emory to the two bores of the yoke. I added a slight chamfer to the lead in of the bores. I did the same thing to the two nuts. I cleaned everything up and got the mic and the telescoping gauge and measured the parts. There is about .001" clearance between the nuts and the yoke. I did instal the y axis nut into the yoke and was able to use the retaining screw to adjust out backlash on the ends of the screw were there is little wear. I have to get a new retaining screw before I can continue on to the x axis.
 
Wow, that seems REALLY tight. I haven't seen nuts need to be pressed out before. Something sounds a little fishy.

Jon
 
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