Subject: Re: an oil pumping bearing

From: [email-masked] (Mark McDade x36841)
Date: Wed, 1 Nov 1995 23:18:31 GMT

. . .

: As I remember, the shims on the SB 9" are in layers of about 0.0005.  I 
: can't say what proper adjustment relates to with regards to turning 
: torque required, just that it should not bind, nor get too hot when 
: running.  It should also not be able to jiggle up and down by hand when 

The book for the SB heavy 10 gives specs for how much the spindle should
move up and down when forced with a test bar of a certain length with
a certain force.  Those bearings are of different construction but it
would be a guideline.  If you want, e-mail me and I'll look up the specs.

. . .

: kept in clean, oiled condition can oval the cast iron bearing.  In this 
: case you may have to re-round it somehow.  You would have to do this 
: anyway if you resleeved the headstock with a bronze shell bearing.  But 

Who/how on the line boring - people talk a lot about it but what do you
do about maintaining or re-establishing the alignment of the headstock
to the bed.  I'm working with a friend on a similar situation on a big
lathe (14' long by 24" swing) and our current best idea is to scoot the
headstock down to the middle of the bed (making sure the bed is well
leveled) and temporarily mount a small lathe headstock at the left end,
running a boring bar through the original headstock from the tailstock
to the temporary head.  We then plan to drive the original headstock
across the boring bar to maintain alignment with the bed.  Does this
make any sense?

Thanks,

Mark McDade

[email-masked]

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From: [email-masked] (Greg Lewis)
Date: Thu, 2 Nov 1995 19:36:10 GMT

[snip]
>across the boring bar to maintain alignment with the bed.  Does this

Yes. This is how Dave Gingery bored the headstock for his DIY lathe in
the well-known series of books. I followed the technique and it came
out right on.

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From: [email-masked] (J. Kimberlin)
Date: 2 Nov 1995 16:46:38 -0800

In article <[email-masked]>,
>across the boring bar to maintain alignment with the bed.  Does this

IMHO, you do line boring on a boring mill.  It is essentially as you say 
but the mill is a separate machine.  If I were to line bore a lathe 
headstock the way you suggest, I would regrind the ways first, then get 
another headstock, scrape it in along with the tailstock....Oh, you see 
the problem.  I think you would be better off going to a place that makes 
racing car engines that line bores the crank bearings.  Your headstock 
center is about 12" and that is about the right size for a car engine 
boring operation.  For a lathe headstock, rigidity is a must as is 
alignment during the boring.  I really don't see how you could slide a 
headstock along the ways and keep it in proper registration with the 
boring bar at all times.  You can't really bolt the headstock to the 
lathe saddle very easily to obtain power feed.  A musing on the idea....

JerryK