Subject: SB Lathe Gear: Can't Dissassemble

From: David Clementson <[email-masked]>
Date: 6 Nov 1995 19:41:53 GMT

Help!!

 I've disassembled my 1939 South Bend 10" down to the last gear, and I 
can't get it apart!!  This is the gear that is on the apron pinion shaft 
that transmits the power feed from the leadscrew to the longitudinal 
feed rack.  It is clearly pinned to its shaft; one end of the pin is 
clearly larger than the other, so I have assumed that it is a taper pin 
(as are used on other parts of the apron).  I can't see any evidence of 
threading or other fastening that would prevent the pin from being driven 
out.  

I have tried everything to get it out short of drilling it through and 
collapsing it.  I filed the small end of the pin flush with the gear body 
to eliminate any mushrooming of the pin end.  I've tried slotting the top 
of the pin to try to twist it out.  I've heated the gear.  I've used 
every kind of penetrating oil and solvent.  I drilled a dimple in the 
small end of the pin to locate the tip of a pin punch.  I have beat the 
daylights out of the pin, bent two punches on it, yet it refuses to move. 
 Actually, when I looked at it under a microscope, it appeared that the 
pin had actually moved _in_ just a little, maybe 0.001"!  

I have three questions:  

1. Is this thing really a taper pin, or am I trying to drive out some 
kind of threaded or welded part?  If anyone else has taken apart a South 
Bend apron, let me know what you found.

2.  If this _is_ a taper pin, how did it get so frozen in place?  Cold 
welding?

3.  How do I get it out?  I'm assuming that I'm going to have to drill it 
and collapse it.  Does anyone have any suggestions on how to make sure my 
drill stays concentric with the pin?  How do I actually collapse it?  

Any help is greatly appreciated, as I'm getting desperate!  

Thanks!  

DC

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From: [email-masked] (Richard W. Klopp)
Date: 6 Nov 1995 23:53:38 GMT

In article <[email-masked]>, David Clementson
<[email-masked]> wrote:

> can't get it apart!!

> 2.  If this _is_ a taper pin, how did it get so frozen in place?  Cold 

It could be that the thing is partially sheared off, due to an overload,
such that the portion in the shaft is no longer aligned with the portions
in the pinion on either side.  It's not hardened, right?, so the best
course is probably to drill it out.

-- 
Rich Klopp
[email-masked]

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From: [email-masked] (J. Kimberlin)
Date: 6 Nov 1995 17:11:32 -0800

In article <[email-masked]>,
>Any help is greatly appreciated, as I'm getting desperate!  

I am a little reluctant to answer but I have looked through my 1964-65 SB 
parts breakdown and not found a taper pin in the assembly you talk 
about.  So I guess between 1939 and 1964, SB has changed some arrangements.

If you have other taper pins, however, this is a good sign that you have 
one here.  I have found that taper pins that remain inplace for centuries 
really do sort of weld in place and you have to drill them out.  Even 
with a hole in them, they are still hard to extract.  I have used dental 
burrs to go through one side to relieve the pressure.  And then had to 
pick them out manually.  They are probably not hard steel.

If possible to accurately center punch the big end, you can drill thru 
then use a taper pin reamer to get out the old steel.  If necessary, you 
can use a bigger taper pin reamer than the old taper pin.  But you have 
to keep track of what you are using so you can re-pin the shaft 
properly.  The handbooks should be able to tell you what drill to use for 
any size taper reamer and your measurements will give you an idea of what 
taper you have to use to clean up the hole.

JerryK