Modding the compound screw nut for backlash.

[Canuck75]

I just finished removing my "compound slide" and I just don't think a second nut is going to work due to the smallness of the slide. There just doesn't seem to be any room. The housing is not build the same way as the SB 10" as pictured above. Maybe try and put a "slight" squeeze, with a vice, on the sides to see how that would work.

You are absolutely right about the lack of room. In my case almost none on the cross-slide either. Depending how much backlash I have to remove on the X next time it might require milling (filing) off some of the flange on the the RH side. Think I used a 20 hole BC on the jam nut thus .005" per hole take-up. Also allowed for a half hole adjustment so .0025" backlash removal. Did the mod in 2012 and needs to be redone - not bad. Used the same jam-nut setup on my mill, also with good results. In the case of the mill the jam-nut doubled the overall length of the nuts.

 

[FOMOGO]

I did something similar when I did the split nut conversion on the Bridgeport, but used an o-ring instead of a spring between the two halves of the original one piece nut, pretty much eliminated backlash, and was still able to use the near zero wear ends of travel on the screw. Have never encountered any issues cutting with this setup. Mike

 

[LX Kid]

You are absolutely right about the lack of room. In my case almost none on the cross-slide either. Depending how much backlash I have to remove on the X next time it might require milling (filing) off some of the flange on the the RH side. Think I used a 20 hole BC on the jam nut thus .005" per hole take-up. Also allowed for a half hole adjustment so .0025" backlash removal. Did the mod in 2012 and needs to be redone - not bad. Used the same jam-nut setup on my mill, also with good results. In the case of the mill the jam-nut doubled the overall length of the nuts.

That's really a great idea! My problem would be making an internal thread in the jam nut. I'm really just a novice at making any kind of inside or outside thread. For my application, in a 6" compound, I'd have to use a long set screw to reach the existing slide nut. Maybe I could drill and tap at the end of the compound slide.

 

[brino]

"What if"using two brass nuts instead of one! I do realize the screw cover will have to be made new to facilitate another nut at the same level as currently exists. Don't know if I can put in words what my idea is so I'll make a sketch in awhile. The screw cover has a step down so is why a new cover will have to be fabricated. A stiff spring between the two nuts would load an opposing force to adjust backlash. I just figure there has to be a workaround for this backlash. Mine is not as major as some being about .006" backlash. My brass nut is new but I have ordered another nut to play around with. If anyone has suggestions besides "forget it" let me know about my folly or how you think this mod might be achieved.

@LX Kid , you are not off-base at all. I have seen this type of arrangement.
Still looking for the reference..... I will try to post back.....

I've included photos of the compound fix on my 10" SB. Very tight space so the jam flange and adjusting holes were made after I knew where the nut would sit. Jam nut can be moved by half a hole.

That's brilliant! I have not seen that kind of solution before.
Thanks for posting!

-brino