# South Bend 16x8 Apron Mystery



## drdudley (Sep 9, 2015)

Has anyone seen this problem before? On reassembly of my apron I find that the idler gear is fully engaged in cross feed while the shifter lever is still about an inch above centering in the "C" slot. The idler gear shifter appears to be correctly oriented and the shifter does center correctly on engagement at the top end. The half nuts are locked out at both ends of shifter travel and free to close in the center. Is it likely that I have somehow switched the location of two components or that an incorrect cross feed gear was installed previously? I do not recall noticing this prior to tear down and did not do any serious work with the machine after it came in to my possession. My concern is that if this is not normal, accuracy in thread patterns and other work may be compromised.


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## aametalmaster (Sep 9, 2015)

What model/size lathe do you have?...Bob


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## drdudley (Sep 9, 2015)

aametalmaster said:


> What model/size lathe do you have?...Bob


SB 16" x 8'


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## kd4gij (Sep 9, 2015)

I am not familiar with south bend.  But is it possible the shaft for the half nuts is 180 deg. out. I  have seen that cause the problem on an atlas.


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## drdudley (Sep 9, 2015)

kd4gij said:


> I am not familiar with south bend.  But is it possible the shaft for the half nuts is 180 deg. out. I  have seen that cause the problem on an atlas.


Thanks for the suggestion. I pulled out the half-nuts and associateds and the problem remains however I was able to get a better view of the idler gear not quite making contact with what I think would be the clutch sleeve gear when the shifter abruply stops. I suspect the problem is hidden right in that vacinity.  What could I have left down there?


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## brino (Sep 10, 2015)

drdudley,

There are some manuals with decent drawings....

like this:


from the document I uploaded in post #3 here:
http://www.hobby-machinist.com/threads/heavy-10-taper-attachment-use.38286/#post-328390

and this:



from the document here:
http://www.hobby-machinist.com/reso...ated-parts-price-list-november-1935-pdf.2460/

If you know the year of your lathe, check the Southbend section of the down loads area for one near your model year. It will be more applicable.
http://www.hobby-machinist.com/resources/categories/south-bend.34/

Also might check here:
http://vintagemachinery.org/mfgIndex/detail.aspx?id=1617&tab=3

Good Luck!
...and please let us know what you find!

-brino


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## drdudley (Sep 12, 2015)

brino said:


> drdudley,
> 
> There are some manuals with decent drawings....
> 
> ...


Thank so much for all this good information. I"m off on a trip right now but Ill get back into it when I return home tomorrow evening.


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## drdudley (Sep 14, 2015)

drdudley said:


> Thank so much for all this good information. I"m off on a trip right now but Ill get back into it when I return home tomorrow evening.


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## drdudley (Sep 14, 2015)

Ok men, I have disassembled the apron and found that somewhere in this machines history, a previously repaired break in the idler gear shifter was not as well done as it appeared. The remachining, after the brazing was completed, was far enough off of exact that the idler gear could not contact both the idler pinion gear and a lower gear (clutch sleeve gear?) at the same time. The gear shifter then would stop downward movement early. This explains the failure to properly cross feed when I bought the machine. With the quality of that repair the machine simply has not functioned in cross feed since it was reassembled. 

So, now I am looking for a few parts to put this machine back in working condition. I will be looking for an undamaged or new idler gear shifter (PT83h1), a missing knob screw (PT355H1, left hand thread?) for the clutch knob,and two ball thrust bearings (AS841T2) for the cross feed screw in rear taper attachment application. Thank to all for your assistance.


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