Subject: Adjustment & Repair of Bridgeports

From: [email-masked] (William E. Lee)
Date: 28 Sep 1994 17:27:53 GMT

Does anyone know of any literature that relates to repair of milling
machines with perhaps particular reference to Bridgeport mills. I have
recently taken over a university shop that includes a Series II that is
less than ten years old, but has been fairly well abused by students and
staff. Bridgeport wants to sell us a new machine. Most machinery
rebuilders want to take the mill off and do a serious rebuild. We can't
afford either at this time. Worst problems are bad x-axis nut or lead
screw, inoperable quill feed and noisey transmission bearings. Anyone have
any experience with correcting these problems on your own? Any info would
be helpful and much appreciated. Thanks, Bill

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From: [email-masked] (James Kirkpatrick)
Date: 29 Sep 94 09:47:32 MDT

In article <[email-masked]>,
[email-masked] (William E. Lee) writes:

|>Does anyone know of any literature that relates to repair of milling
|>machines with perhaps particular reference to Bridgeport mills. I have
|>recently taken over a university shop that includes a Series II that is
|>less than ten years old, but has been fairly well abused by students and
|>staff. Bridgeport wants to sell us a new machine. Most machinery
|>rebuilders want to take the mill off and do a serious rebuild. We can't
|>afford either at this time. Worst problems are bad x-axis nut or lead
|>screw, inoperable quill feed and noisey transmission bearings. Anyone have
|>any experience with correcting these problems on your own? Any info would
|>be helpful and much appreciated. Thanks, Bill

Though I don't have a copy myself, others have praised the book
"Machine Tool Reconditioning" by E.F. Connelly.  This is available
>from  Lindsay's, catalog number 1141, $38.50.  Their phone number is
(815) 935-5353.

Jim

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From: [email-masked] (Joe Landau)
Date: Fri, 30 Sep 1994 04:43:40 GMT

>from Lindsay's, catalog number 1141, $38.50.  Their phone number is

I have that book; it does discuss mills, but there is no reference to
Bridgeport in the index.

Joe

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From: [email-masked] (Alan Frisbie)
Date: 4 Oct 94 09:25:19 PST

In article <[email-masked]>, 
[email-masked] (James Kirkpatrick) writes:
> |>machines with perhaps particular reference to Bridgeport mills.
> |>Worst problems are bad x-axis nut or lead
> |>screw, inoperable quill feed and noisey transmission bearings.
> 

Although this is an *excellent* book (and you should probably
have a copy), it does not cover the items you mention as needing
work.   "Machine Tool Reconditioning" assumes that you are
going to strip the machine down to a pile of castings and
rebuild it from the ground up.   The first third of the book
covers hand scraping and related testing techniques to ensure
that everything is flat/parallel/perpendicular/etc.   The
rest of the book is divided by class of machine: lathe, mill, etc.

Since you are lucky enough to have a Bridgeport, the maintenance
manual is available.   Call 800-243-4292 and you will be connected
to your nearest Bridgeport dealer (not Bridgeport themselves).
Give them the model & serial numbers and they can look up
the part number for the maintenance manual.   

I just bought the maintenance manual for my Bridgeport
Series I CNC mill.   It cost $184, but is worth every cent.
The manual for your machine should be much less, since there
are many fewer parts.

They will also have the replacement parts you need.   This is 
also probably the only place you will find Lubriplate #107 for 
greasing the Hi-Lo sleeve.   According to "old timers" it 
comes in a tube that screws directly into the 5/16"-24 "A" 
hole.   However, the tube I bought has a different thread
that is somewhat smaller.   It appears to be ordinary white 
grease, but Bridgeport seems to think there is something
magic about it.

If you really *must* talk directly to Bridgeport, their
number is 203-367-3651.   They will not sell the manual
directly to you, however.   You will be referred to your
local dealer.

--  Alan E. Frisbie               [email-masked]
--  Flying Disk Systems, Inc.
--  4759 Round Top Drive          (213) 256-2575 (voice)
--  Los Angeles, CA 90065         (213) 258-3585 (FAX)

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From: PAUL <[email-masked]>
Date: Wed, 5 Oct 94 23:16:01 -0500

>>|>screw, inoperable quill feed and noisey transmission bearings. Anyone have
 
Bill, Generally, the replacement of your bronze nut for your X axis will help
your backlash problems but if the table gets loose in the middle, and tight on
the ends when cranking a rebuild is in order. Perhaps your students
climb-milling have ravaged
the nut, and a replacement for that might do the trick. as for the power feed,
if it is failing to engage/disengage properly you might try adjusting either
the set screwon the bottom end of the vertical rod on the left side of the
milling
 head. The top of it is anchored to a "tuna can" looking aluminum casting. the
bottom has a fork, with a #10 or so set screw horizontally screwed into it. Try
adjusting it in or out to achieve engagement. As for dis-engagement, there is
another set s
crew underneath the 1/2 - 20 rod that is used for setting depth. It is located
on the front of the head (the one with the graduated nut on it) a set screw is
directly underneath this rod, propping it up to achieve the proper adjustment.
they generally
become mis adjusted when the quill lock is left on too tightly causing wear
and/or slamming of the mechanisim. The problem with your transmission "grinding
can sometimes be solved by moving the small block on the right side of the
head, that the "back ge
ars" are selected with. there is a pin that slides onto a hole in this block.
The position of this block is fairly critical to the "grinding thing". I
believe on Bridgeports, the block is held in place by a set screw that faces
the operator, wh
ich screws through a "housing block" and holds the "pin block" in its proper
vertical position to prevent grinding.
Hope this helps you out. Pardon the semi- incoherrent writing skills. Its WAY
past my bedtime. Feel free to E-mail me if you have more questions. Paul

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From: [email-masked] (Barry Workman)
Date: Thu, 6 Oct 1994 04:43:27 GMT

>be helpful and much appreciated. Thanks, Bill

"Machine Tool Reconditioning" available through Lindsay Publication
is a starting point.  My friend owns a Bridgeport CNC mill and all
of the manuals needed were still available through the local 
Bridgeport dealer.

"Machine Tool Reconditioning" is a *VERY* complete work on the
techniques of reconditioning machine tools.  It starts with
scrapers, how to use them, different types, even how to make your
own from old files.  It then takes you through the philosophy of
reconditioning.  Finally it takes you through each different type
of machine and how to approach the reconditioning.
-- 
    - Barry Workman

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From: [email-masked] (Ken Moonitz)
Date: Thu, 6 Oct 1994 19:25:27 GMT

In article <[email-masked]> PAUL <[email-masked]> writes:
>the nut, and a replacement for that might do the trick.....

Note the Bridgeports use a split nut so the backlash from the nut can
be adjusted.  HSM had an article on CNC retrofit and had a good section
on setting up preload/backlash of the bearings at the end of the lead
screws, this can also be a source of backlash.  Heres something else
to check,  I got my table to move real smooth in the center but got
tight at each end.  If you adjust the split nut this would help the
ends of the lead screw but put excessive lash in the center.  The problem
was the casting that the bronze nut sits in was not in line with the
lead screw so there was enough flex in the screw to be smooth in the
center but bind towards the ends.  The casting (which holds both nuts)
bolts to the knee with 4 bolts.  I just enlarged the holes to allow
adjustment, made a big difference.
					 Ken