SouthBend 9A cross slide nut question

josef

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I have a 1951 SouthBend 9A lathe that is set up metric. I am going through the Guide to Renovating the lathe and it says that once you remove the gib screws and slide the cross slide off, then the cross feed nut are easily removed. Well.. after I removed the cross slide I removed a set screw or grub screw with a conical end from the top of the cross feed nut. The nut is not loose. I don't want to force anything. When I look down into the hole, see picture, I see a little point sticking out that the conical set screw must have been bearing on. ?? Does anyone know what I should do now? Is that point just the end of a pin that bears against the cross feed nut hole and if I twist the nut some it will come loose?cross-slide.jpg
 
You have to unscrew the entire cross slide. Simply turn the handle to move the cross slide to you. At one point it will dis engage. At that point simply slide it the rest of the off. The nut will most likely fall out for you.


Cutting oil is my blood.
 
You have to unscrew the entire cross slide. Simply turn the handle to move the cross slide to you. At one point it will dis engage. At that point simply slide it the rest of the off. The nut will most likely fall out for you.


Cutting oil is my blood.
Did all that already. The nut is pretty solidly in place. But looking ahead a bit in the Guide it shows a better picture of the nut and the locking pin and the set screw. I think that the nut is just gummed up so I'll let it soak in some penetrating oil and work it back and forth a bit to free it. I had to do the same sort of thing with the compound's nut.
 
Yeah I think you just need to wiggle it and jiggle it, maybe tap on it with a chunk of wood to get it loose
 
That pointy screw is merely plugging the oil hole, it does not secure the nut.
 
That pointy screw is merely plugging the oil hole, it does not secure the nut.
it actually does secure the nut.
There is a cross pin in the nut cylinder that has a matching pointed pin. That pin is pressed on from the screwed ones point. it excersizes pressure to the wall of the bore.

Like has been said, if you remove the cross slide from the carriage, the nut should be loose. If it's not, the cross pin is probably frozen in place. Don't worry, a quick hit with a hammer should loosen it up. Use a wooden dowel on top, support the slide on 2 2x4s and give it a quick blow. it should loosen it up. if not, turn it over and give it a tap (not too hard you don't want to deform the nut) it should wiggle out now.
 
it actually does secure the nut.
There is a cross pin in the nut cylinder that has a matching pointed pin. That pin is pressed on from the screwed ones point. it excersizes pressure to the wall of the bore.

Like has been said, if you remove the cross slide from the carriage, the nut should be loose. If it's not, the cross pin is probably frozen in place. Don't worry, a quick hit with a hammer should loosen it up. Use a wooden dowel on top, support the slide on 2 2x4s and give it a quick blow. it should loosen it up. if not, turn it over and give it a tap (not too hard you don't want to deform the nut) it should wiggle out now.
I got it. Grease and oil mixed with dirt seem to turn to glue over the years.
 
Here's an assy drawing for you:

View attachment 449927
Thanks. That is very helpful. All for now. I've got it reassembled after adding some brass shim washers to reduce the play in the cross slide. It looks like I've got a little over .015" backlash in the lead screw/nut combo. I set up a dial indicator to help me see when the cross slide moved. Turned the handle one way, set the collar to zero, turned back the other way and it looks like 0.4mm rotation before the slide moved.
 
Thanks. That is very helpful. All for now. I've got it reassembled after adding some brass shim washers to reduce the play in the cross slide. It looks like I've got a little over .015" backlash in the lead screw/nut combo. I set up a dial indicator to help me see when the cross slide moved. Turned the handle one way, set the collar to zero, turned back the other way and it looks like 0.4mm rotation before the slide moved.

.015 is really good. I would love to have that on my old Wards lathe. My SB9 has .012 and it was in killer shape when I got it. Just 70 years of sawdust in it.


Cutting oil is my blood.
 
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