Bronze Cross feed nut....ain't eating !!

The Evan I know posts on the "Home Shop Machinist". I have been a friend to him and exchanged many PM's. He's a brilliant guy,but really in declining health. I don't know if he is still alive. I quit posting there because the atmosphere is just too hostile. Guys like Lazlo,Stevenson,Muller,and a few others are a PITA gang that make it unpleasant to post there,so to heck with the lot of them. Evan always got harassed by them. I don't know why he stays there.
 
From what I have read so far the plastic nuts work great in the beginning but tend to wear out quickly.. Ray
 
look for jay hawk machining on ebay, he sells the crossfeed and compound nuts for many of the home shop type machines, including southbend. i got a combo of crossfeed and compound for my heavy 10 from him for like 50 bucks. they work well and took out most of my back lash, i should have re made the screw but it is still better. i think he sells the feed rod as well.
 
Here is the plan. I found a sleeve nut at 5/8-8 LH acme which (I'm going to double check after I post this) I believe I can turn down a little and bore the worn out cross feed nut I have (a little) press it in and secure ...and that is done! I will also purchase 5/8-8 acme rod cut off the worn acme from the shaft and sleeve the shaft over the new acme rod pin or silver solder. That should work ...I can't find 11/16-8 but that shouldn't be a problem ?? that is the question ,I can't see the 5/8-8 making any difference. I like the acetal idea but I probably won't wear the bronze out in this lifetime....Let me know if you foresee any faults with this plan Thanks and Regards

PS i'll post pictures as I go
 
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Soooo, I got the threaded left hand 5/8 acme rod .....Needed a foot but had to buy a 3' piece from McMaster-Carr which was here overnight for regular shipping price(Nice) I also ended up getting a new nut 5/8 LH Acme, but that is not here yet....I was going to try to locate another lathe to use because my other lathe is to small for the rod to fit through,then I got to thinking....and ended up putting the crossfeed back on where I needed it and tightened down the gib then used the compound as the crossfeed....that worked out ...last photo was the new threaded rod being turned ...The pics should speak for themselves?

lathe repair 001.JPG lathe repair 002.JPG lathe repair 004.JPG lathe repair 007.JPG lathe repair 008.JPG lathe repair 005.JPG
 
rafe said:
....seems like some play in the thrust bearing too.
Can someone or more offer me advice on this.
Click to expand...

This crossslide does not have the thrust washer set up, They must have started that after 47...There is however a lot of play in the dial .024....I am tempted to put in a thin washer to take out some of the play (does anyone know what the play should be??) but don't know if it's even nesessary to worry about it....I don't think I want to modify it for the thrust bearing set-up. Thanks and regards
 
I had to fix the cross feed on my 14 1/2 a few months ago. I couldn't find the 11/16 screw unless I wanted to pay for a custom order. I ended up getting a 11/16 nut from Jhawk and cutting my own screw. It worked out well but it would have been a lot easier to do it your way with 5/8.

Chuck
 
Rafe,

I don't own an SB and don't know what the typical minimum backlash is. However, the back lash (that shows up in dial reading) has two sources. One is clearance between the cross feed screw and nut threads. There is little that can be done about that other than reducing it to a minimum by replacing both parts. The other is end float in the feed screw. On a machine without ball thrust bearings, the theoretical minimun is zero. Or if you prefer, zero+. Get it any tighter and the crank gets difficult to turn. On my Atlas this is adjustable and I'd guess that after several tries I could typically get it down to .001-.003.

If yours isn't adjustable, what you could do is first run the cross slide off the end of the feed screw (assuming that you can do that) to take the nut out of the equation. Rig a dial indicator to measure screw end float. Buy an assortment of thicknesses of of appropriate diameter bearing shims from some place like McMaster and play with them until you reduce the end float to the minimum you can get it to without having objectional drag on the crank. Then reengage the nut with the screw and see how much backlash you have. That's as good as it's going to get. Same principle should apply to the compound.


Robert D,

rafe said:
This crossslide does not have the thrust washer set up, They must have started that after 47...There is however a lot of play in the dial .024....I am tempted to put in a thin washer to take out some of the play (does anyone know what the play should be??) but don't know if it's even nesessary to worry about it....I don't think I want to modify it for the thrust bearing set-up. Thanks and regards
Click to expand...
 
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