# Fix for Broken Leadscrew Bearing 07403:



## TinkerToy (Jul 14, 2014)

I noticed that my bearing support, 10F-16, was cracked and I removed it for repair.  Surprise, it melted when I tried to weld it!  I felt real bad and looked and hoped for a replacement.  I was glad to see that they were available, but a little pricey.  So I decided to try to make one myself, it is not a highly stressed part and I had nothing to lose.
I cut the bearing housing off of the bracket and turned it down from a football shape to a cylinder.  Then I made an aluminum ell bracket and attached it to the lathe.  I put the bearing cylinder on the leadscrew and operated everything to find it's center.  Then all I had to do was to pot the bearing cylinder into the ell bracket with JB Weld while everything stayed in place.  This somewhat retains the stock look and uses the original bearing for its purpose.  I hope the pictures explain it better than I did.
I love my lathe.
JD


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## Walt (Jul 14, 2014)

Nice work! 

Looks like it will operate as well as a replacement part and you got to be creative as a bonus.

Walt


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## Ulma Doctor (Jul 14, 2014)

Sweet!
nice repair work!!!
the Zamak crumbles after a long time, or after a crash whichever comes first! :lmao:


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## kd4gij (Jul 14, 2014)

While most people make that part more rigid than the stock part. It was meant to be the weak link in the drive train. In the event of a crash it breaks and the lead screw disengages and saves the drive train.


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## JOEZ (Jul 14, 2014)

I made Mine out of a 2X2 block of Aluminum.
I had the same Problem.
kd4gij Made a very good point.
This block is Designed too Lift & Break when (Human Error) some thing happens.
I used a Ball mill to cut the Break away Design.


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## Mondo (Jul 18, 2014)

kd4gij said:


> While most people make that part more ridged tham the stock part. It was ment to be the weak link in the drive train. In the event of a crash it breaks and the lead screw disengeges and saves the drive train.




This is true, and documented in the Atlas manual.  But I can't resist the temptation to comment:
Pay attention to your work and don't crash the lathe!  Follow that rule and this is not a problem.


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## kd4gij (Jul 18, 2014)

Spiral_Chips said:


> This is true, and documented in the Atlas manual.  But I can't resist the temptation to comment:
> Pay attention to your work and don't crash the lathe!  Follow that rule and this is not a problem.






  While I do agree, some times things happen we can't controll.


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## wa5cab (Jul 19, 2014)

And of course the sacrificial right bearing idea only works if the left end of the lead screw isn't frozen into the hole it fits into.:whistle: 		

Robert D.


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## kd4gij (Jul 19, 2014)

wa5cab said:


> And of course the sacrificial right bearing idea only works if the left end of the lead screw isn't frozen into the hole it fits into.:whistle:
> 
> Robert D.





 Verry true. That why it is a good idea to keep your machines in good working order at all times.


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## cathead (May 1, 2017)

On You-Tube there is a video on just this subject by Tubalcain(Mr. Pete 222)   #321


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## CluelessNewB (May 1, 2017)

Back in the dark ages when I was about 11 years old....   My Dad had an older 12" Atlas, it was probably around 1968 he added a quick change gear box which I believe he purchased from Sears.  I also remember him adding a lead screw bearing that was black and brass with roller thrust bearings.  I vaguely remember that was not part of the package that came from from Sears but rather came from another supplier.  I don't know if the new lead screw had a shear pin or some sort of slip clutch.


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## wa5cab (May 4, 2017)

If the lead screw right bearing block was brass, it was made by someone other than Atlas.  The right bearing assembly on the final version Atlas 12" machines is all steel.  And they do all have a slip clutch on the left end right next to the QCGB.  Although the QCGB that will fit the 101.07403 can be converted to carry the slip clutch on its right end, AFAIK Atlas never sold it "pre-converted".  Your father would have had to buy the gearbox (I think that in 1968, they were still available from Atlas (Clausing) or Sears and buy the additional parts for the conversion.  The QCGB model that came with the slip clutch will not fit a 101.07403.


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