Subject: moveable quill

From: "Steven O. Smith" <[email-masked]>
Date: Wed, 4 Dec 1996 21:04:05 GMT

I have an older mill (Van Norman #12) which does not have a moveable
quill. To change the cutter to table distance, you need to move the
table. I would like to make a moveable quill for it to make things like
drilling a bit easier.

How are moveable quills put together? If anyone can point me to drawings
on the net or by paper reference, that would help a lot.

Thanks,
-- 
Steven O. Smith
[email-masked]

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From: [email-masked] (Jonathan M. Elson)
Date: 5 Dec 1996 06:48:55 GMT

Steven O. Smith ([email-masked]) wrote:
: I have an older mill (Van Norman #12) which does not have a moveable
: quill. To change the cutter to table distance, you need to move the
: table. I would like to make a moveable quill for it to make things like
: drilling a bit easier.

: How are moveable quills put together? If anyone can point me to drawings
: on the net or by paper reference, that would help a lot.

Bridgeport quills are made from a tube of steel (I think), ground on the 
inside to hold the bearings, and chrome-plated and ground on the outside. 
The outside of the quill is ground to a mirror finish, and presumably  
VERY accurately to a cylindrical shape, coaxial to the inner bore.    
The quill is a very fine slip fit into the quill housing, which is normally 
a grey Iron casting.  it is accurately bored to about the same diameter 
as the quill.  I don't know what the clearance is between quill and housing, 
but it is quite small, certainly less than a thousandth.  The upper part 
of the housing is bored something like .080" larger, and a 'skirt' made 
of rolled .040" sheet steel fits between the quill and housing.  On the 
Bridgeport 'M' head, it is brass, but otherwise similar.  I've never 
understood the purpose of these skirts, and if someone would like to fill
us in on what they do, I'd appreciate it.  I believe they may have something
to do with providing a more even film of lubrication to the top of the
quill slide through capillary action, but I'm guessing.  On the Brodgeport
J head, the skirt is attached to the top of the quill.  On the M head,
it is free-floating between it's upper and lower limits.

Anyway, there is more:  The Bridgeport machines have a very elaborate scheme
to allow one lubricant port to drip lubricant from the top of the machine,
lubricating the driven belt pulley bearing, then the quill, then the top
spindle bearing, and finally the bottom spindle bearing.  From this point,
the spindle oil leaks out around the spindle nose.  Very clever!

I'd suggest, before you try to design your own, you get someone to let
you watch them take apart a Bridgeport J head, so you can see how the whole
contraption works.  The drawings don't show many of the intricate details
of how lubrication works, finishes and clearances, etc.

Another thought, why BUILD a VERY complicated and precise mechanism?
Find a used Bridgeport (or clone) mill head, and adapt it on your machine.
These do exist - I got a used J head that came off a giant gantry contouring
machine.  There are also Bridgeport dual and triple head machines which
are often converted back to single head for resale, and the extra heads
are sold separately.  Look around.

						Jon

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From: ANDY POPKY <[email-masked]>
Date: Thu, 05 Dec 1996 20:56:27 -0500

it is accurately bored to about the same diameter
> as the quill.  
actually it is honed on a SUNNEN cylander king

I don't know what the clearance is between quill and housing,
> but it is quite small, certainly less than a thousandth.
the clearance between the the quil & housing is .0002"
the size of each housing is stamped on it, the trick is 
to know were it is stamped if anyone is interested ask
and i shall tell

  The upper part
> us in on what they do, I'd appreciate it.  
nothing to do with lubrication
it keeps the dirt out of the spindle bearings
with the quill at the bottom
and if the skirt was removed you would see the top 
of the top spindle bearing

I believe they may have something
> quill slide through capillary action, but I'm guessing.  
good theory but wrong<w>

On the Brodgeport
> the spindle oil leaks out around the spindle nose.  Very clever!
not true there is a oil cup for top of the head and for the quill
housing

> of how lubrication works, finishes and clearances, etc.
i suggest saving many many hundreds of hours trying to build one
and buy one instead

> are sold separately.  Look around.
yup i got them for sale

regards
andy popky
x-bridgeport employee

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From: [email-masked]
Date: 6 Dec 1996 04:57:45 GMT

i agree with jon . i to have an old van norman .if yours is anything like
mine i think you will find it impractal if not imposable. pardon the
spelling as i am just getting over a bad case of the flu.i got as far as
converting it to use r8 tooling because i could not find any original
tooling and the teper was close to begin with. jamie

jcranegt90