# Quick and dirty fix.



## toolman (Dec 8, 2013)

Hey guys, I just thought I'd pass this along. A few nights ago, I was at the shop trying to get a parts list together for my old 12x36 lathe and trying to figure out how I could make/repair some of them. I came up with some ideas, then started putting the carriage back together and remembered that the cross slide nut was really loose. I didn't want to put it back together that way, so I got the bright idea to tighten it up. I used my bandsaw to slice it lengthwise all the way into the bottom part of the threads, then I clamped it in my vise to close the gap back up. I filed a V along the split and then brazed it back together, after test-fitting the screw. Afterwards, the screw was extremely tight due to a bit of brass that flowed down into the threads, so I used some 220 grit lapping compound and lapped it in. I don't know how long it will last, but right now, there is no discernible play in the cross feed at all and it's slick as glass. The whole process took maybe minutes and saved me over $40. )


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## iron man (Dec 9, 2013)

I made a tap out of drill rod and made a brass nut twice as long as the original works great and should last twice as long too. It was kind of hard to get the tap through a piece that long but it just took time.. Ray


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## toolman (Dec 9, 2013)

Oops, I meant 20 minutes.


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## Restorer (Dec 9, 2013)

Splitting and squeezing the nut is a good idea and will work as a temporary fix to reduce backlash.  

However if the thread has worn reducing its tooth thickness, this method dosn't address that issue.
Also it is not a good idea to put lapping compound in a bronze nut.  The grit will imbed into the softer bronze and wear the steel screw for years.

A better solution is to make or buy a replacement nut.  Be certain to clean any trace of lapping compound off of the screw prior to reassembly.


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## Restorer (Dec 9, 2013)

Splitting and squeezing the nut is a good idea and will work as a temporary fix to reduce backlash. 

However if the thread has worn reducing its tooth thickness, this method dosn't address that issue.
Also it is not a good idea to put lapping compound in a bronze nut. The grit will imbed into the softer bronze and wear the steel screw for years.

A better solution is to make or buy a replacement nut. Be certain to clean any trace of lapping compound off of the screw prior to reassembly.


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## Dranreb (Dec 9, 2013)

iron man said:


> I made a tap out of drill rod and made a brass nut twice as long as the original works great and should last twice as long too. It was kind of hard to get the tap through a piece that long but it just took time.. Ray



Hi Ray, I'm sure you know this and make allowances in use, but just to make others aware of a potential problem with using a longer nut.

On Atlas lathes with power feed to the cross slide, at the apron end there is an inch or so of screw turned down to the minor diameter, this uncouples the lead screw before the nut hits the casting and causes damage.

Luckily I noticed this before anything happened, when I fitted a spare nut that came with my lathe which was a little longer than standard.

So best to check any aftermarket nut for length before fitting.

Bernard


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## sniggler (Dec 9, 2013)

A dirty fix in the same vein. Many times in steel construction we have anchor bolts cast in concrete that the column bases are bolted down with. No surprise the threads get mangled some times. The bolt are long to allow for shimming. So running the die down can be a pain so we use an impact gun with a field fabricated deep socket usually wobbly. Of course thats no way to treat a die nut and it fractures. The company doesn't want to keep sending out 40 dollar die nuts (big anchor bolts cost even more) and we can" wait anyway so you take a regular nut for the anchor bolt and cut a slot right through to the threads on one flat costs a buck fifty and lasts ten times longer than the die nut. Hell of a thread chaser if you are in a pinch. 


Bob


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## toolman (Dec 10, 2013)

Restorer said:


> Splitting and squeezing the nut is a good idea and will work as a temporary fix to reduce backlash.
> 
> However if the thread has worn reducing its tooth thickness, this method dosn't address that issue.
> Also it is not a good idea to put lapping compound in a bronze nut.  The grit will imbed into the softer bronze and wear the steel screw for years.
> ...



I didn't think to post the clean-up process. I washed the screw in my parts washer, then chucked up a bronze-phosphor 12 ga. cleaning brush on a section of cleaning rod in my cordless drill. I submerged the nut in the parts washer and ran the cleaning brush forward and backwards through the nut several times. 
I wouldn't recommend this as a long-term fix, but it is worlds better than living with a quarter turn of slop in the crossfeed, plus 20 min. trumps a week waiting on parts every time in my book. I'll try to keep everyone updated as to the longevity of this little experiment. Building a new nut was the first thing that crossed my mind, but it's hard to do when your carriage is scattered all over the bench...)


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## iron man (Dec 10, 2013)

Dranreb said:


> Hi Ray, I'm sure you know this and make allowances in use, but just to make others aware of a potential problem with using a longer nut.
> 
> On Atlas lathes with power feed to the cross slide, at the apron end there is an inch or so of screw turned down to the minor diameter, this uncouples the lead screw before the nut hits the casting and causes damage.
> 
> ...



 Yes I knew about that when I replaced the cross feed screw I elliminated that feature as well I found it to be an irritating feature and no other lathe I ever run had that you just have to watch what your doing. Ray


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## wa5cab (Dec 11, 2013)

The problem in this case is that you quite literally can't see what you are doing.  Fortunately, running the power cross feed in reverse isn't done much.  I wonder what part would break?

Robert D.



iron man said:


> Yes I knew about that when I replaced the cross feed screw I eliminated that feature as well I found it to be an irritating feature and no other lathe I ever run had that you just have to watch what your doing. Ray


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## Dranreb (Dec 11, 2013)

wa5cab said:


> The problem in this case is that you quite literally can't see what you are doing.  Fortunately, running the power cross feed in reverse isn't done much.  I wonder what part would break?
> 
> Robert D.



Hi Robert, I use my power cross feed quite often in reverse when facing a large piece and when milling/fly cutting.

 For milling I use a Myford milling attachment fitted to an Atlas 'turret lathe' slotted cross slide, this cross slide is the wrong shape for the 'uncoupling system' to work, I found this out the hard way!

All that happened was that the cross slide hit the crank handle, which jammed the whole thing up tight, luckily one belt was loose enough to slip so there was no more damage than a very slightly wobbly crank handle due to the lead screw getting bent, almost unnoticeable though and not worth trying to straighten in case that makes it worse.

It was quite a struggle getting it unjammed.

Tighter belts might have meant more broken parts, because the sacrificial traverse lead screw bearing would not have failed safe as the half nuts weren't engaged.

My old man used to say 'It doesn't matter what you do in life as long as you learn something every day' I learned very quickly that day!

Bernard


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## iron man (Dec 11, 2013)

wa5cab said:


> The problem in this case is that you quite literally can't see what you are doing. Fortunately, running the power cross feed in reverse isn't done much. I wonder what part would break?
> 
> Robert D.



 I dont use the cross feed much and even when I do I have my cutter moving in not out but even then I know how much travel the compound has and I just stop short. Ray


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## wa5cab (Dec 11, 2013)

Ray,

OK.

Bernard,

If you mean the #9-671 or L6-671 slide for the Atlas or Craftsman Cross Slide Turret, I have the former, With both tool posts and stops.  I haven't had mine on the machine yet but setting it across the saddle and lining up the cross feed nut hole with the screw head on the regular cross slide, it looks as though the front will just clear the ball on the crank with the nut free of the threads on the cross feed screw.  But I'm glad that you mentioned this as I will certainly check that clearance first time I use it.

Does yours have two T-slots on top (one left to right and one front to back) or three (two front to back)?

Robert D.


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## Dranreb (Dec 11, 2013)

Ray, mine is 1 1/4" longer than the normal slide measuring from the nut screw to the front. So maybe mine is a L6-671, the L meaning long ?






Bernard


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## wa5cab (Dec 11, 2013)

No, you have the 9-671, like mine.  The L6-671 has two parallel slots at the front. 

 I've always assumed that "L" was for "Lathe".  Which doesn't explain why so many 618 part numbers start with "M6".  The Atlas part numbering system apparently went through versions over the years.  9" parts mostly began with "9".  10" with "10", then "10D" and then "10F".  The "L" first appears in 1937 on parts for the 101.07400, 101.07380 and 101.07360.  Don't know why they didn't use "12", "12A", etc.

Back to the subject at hand, my 9-671 is also 1-1/4" longer than the standard cross slide, measured from the cross feed nut mounting hole.  But I have a 3996.  The cross feed crank may be slightly farther away from the end of the threads.  Most of the part numbers in the carriage and cross slide are different between your lathe and mine.  In your case, I think that I would cut a little off of the front of the turret cross slide.

Robert D.


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