What do y'all think about this ?

Thanks, Ken. I got a quote from Brian Miller for screw and nut. He claims the backlash on his set up, assuming all is well with the rest is around 0.003 to 0.006.

The first thing I did was fix the nut at the end of the screw by the taper attachment. The thrust washer was bottoming out on shaft shoulder, but not against the housing. I could literally push the screw back and forth. I machined a pocket in the washer so it goes over the shoulder and bear agains the housing. Polished the side of the washer. The backlash went from about a full rev down to 0.080.

I might take you up on the offer. Would the ACME rods from McMaster good enough?
 
Bamban said:
Unfortunately, the 6J set thru is mine, it is just too big for my 1236, perfect for this 13.

I still have to do the final leveling, just rough leveled it to see what she can do. It is still on skates, but leveled good on the HS end and the mounting bolts on the TS side relaxed.

I am thinking about outrigger type base with levelers on 4 corners on the HS end , and 2 levelers on the TS side.
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I think you got a great deal . It all looks good to me
 
Bamban said:
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I might take you up on the offer. Would the ACME rods from McMaster good enough?
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It will probably be fine as long as you fit the nut to the thread. If they have a 3C or 3G class fit, get it. This class of fit will have a tighter pitch diameter on the thread that you will have on a class 2G thread. You have .0154" of tolerance variation on a Class 2G thread. Where on a class 3G thread, you have a tolerance variation of .0072". Does not mean that you will have that much variation in a section of Acme all thread, but you could. (I based this on a 5/8"-8 pitch Acme thread.) Need to check your cross feed screw and see if it is 5/8" OD or 11/16" OD.
 
Ken,

The threaded ACME rod is 2C.Screenshot_20170622-210154.png
 
I rather it be a class 2C rather than 2G tolerance fit. The "C" indicates that it is a "centralizing" fit thread. The thread axis locates off of the OD of the male thread and minor diameter of the internal thread. Where as the class 2G tolerance fit is a "general purpose" fit, which means, it has lots of slop in the clearances of the thread.

Give it a try! I might even offer to buy some of the left over of the all thread from you to use on my lathe later on.

Get me some overall dimensions of the nut and I'll get you a piece of bronze in the mail for you next week.

Ken
 
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Bamban said:
Ken,

Here is a nut on eBay quoted 4G. For the price for around 100 bucks combined with the rod, compared to 250 already done up, it may just be worth it to tackle finishing the ends of the rod.

Thoughts?

http://m.ebay.com/itm/South-Bend-Lathe-13-Cross-Slide-Feed-Nut-PT65T1-/201948182257?hash=item2f050cb6f1:g:5jsAAOSwNyFWeyk2&_trkparms=pageci%3A573bd7b0-57c6-11e7-bdf9-74dbd180ccee%7Cparentrq%3Ad30d9c9515c0aa469480e93affffa178%7Ciid%3A15
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Let's see, 2C plus 4G = Slop. Just depends on which end of the spectrum the 2C thread is cut to. Generally, I would say, it is cut to the high end of the tolerance limits for 2C. 4G, in my book that is a metal to metal fit if fitting two 4G fits of threads together. The slop, as I indicated, is probably no more than .005" to .007" clearance between the two threads. I usually cut them to where is around .001 to .003" clearance.
If you can live this, I say go for it. I can live with it!. Now, don't be surprised if when you get the all thread and thread the nut on it and find tight and loose places in it as you rung the nut from end to end. And it may not. Still worth a try. You can always set up and chase the thread on the screw and make a nut to fit close if your not happy with the fit. I've done this on worn cross feed screws in the 4 and 5 pitch range.
Ken
 
I want to correct the cross slide backlash right the first time, whatever it takes.

On another note, made a little progress in cleaning. I've been tied up helping the TX JRs on the firing line since Wednesday.

20170618_191904.jpg 20170623_113127.jpg
 
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Looks a lot better, I'm jealous too. I'm guessing the color was grey originally?
Mark S.
 
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