Bridgeport repair

[Lew Hartswick]

We have a problem at school, one of the Bridgeport mills
the power quill feed did not work. The "push-pull"
direction reverse pin in the center of the hand crank
for fine feed just pulled clean out. The pin hole in the
end obviously was not doing whatever it was suppost to do.
SO! dug out the file folder and looking at the various
picts. and then taking apart the various bits to get in
to the area no problem untill I get to the clutch that
should be free to slide in / out and engage one of the
two bevel gears (that the pin was suppose to operate)
was frozen tight on the shaft. with the front miter
gear off it is not obvious how the shaft with the other
miter gear the clutch and the worm on the rear end can
ever be pulled out because the "input" bevel gear
(the one that is vertical) won't let the drive shaft
come out past it. Removed the "gear shift" box cover
with (the carrier that slides the cluster up and down0
and I don't see any way to either move the gear up or
remove it. It looks like the clasic "catch 22" sit.
(Incidently that gear box is a clasic manual crash box)
Very cute.:-)
Has anyone been in to that part of a Bridgeport?
This is, I guess it's called, a J head, at least the
serial no. is J236648 The book we have is called
"Operating Manual 1962" the pictures of the
"Feed Transmission Unit" on page 27 and
"Quill Unit" on page 19 ff

Here are links to the two page pictures. My Photobucket
is not working for some reason with this browser.
I am having to use FireFox since my up grade of SeaMonkey
crapped out on me.(no bookmarks or e-mail got copied)


http://home.earthlink.net/~lhartswic...20and%20W..jpg
http://home.earthlink.net/~lhartswic...%20and%20W.jpg

...Lew... On edit I got the pix on Photobucket so here they are "I hope"

[wierdscience]

IIRC the top housing and all it contains must come off first.It seperates off the head at the point where the aluminum top housing ends and the cast iron begins.I can't remember if there are three or four bolts that hold the housing and allow it to swivel,but you remove those and the whole mess comes up and off.

Once that's gone the top end of the feed shafts should be accessible.The vertical shaft comes out the top IIRC.It's been awhile since I've gutted one.

[Lew Hartswick]

Weird, It dosen't look like that will be able to slide the shaft with the cluster
gears on up anyway. That is the one that seems to be blocking the removable
of the horizontal shaft.
But thanks. If we have to remove the entire top (motor and pulley assy.) it's
going to require some real lifting. :-(
...Lew...

[lakeside53]

Oh.. it's a real joy.... You need to get the vertical shaft out first, and that's done by tapping from the bottom.


Tom Jelly's blog covers it...

http://home.comcast.net/~tom.jelly/j...%20rebuild.htm

[wierdscience]

Weird, It dosen't look like that will be able to slide the shaft with the cluster
gears on up anyway. That is the one that seems to be blocking the removable
of the horizontal shaft.
But thanks. If we have to remove the entire top (motor and pulley assy.) it's
going to require some real lifting. :-(
...Lew...

Lew,no lifting required.Tilt the head over 180*(upside down) support the top housing and motor with wood blocking on the mill table.Remove the three nuts that hold the housing on.Crank the knee down til the studs clear,then crank the table one way or the other to get the housing out of the way.

Lake,that's a neat page.I really like the dolly,but I would turn it 90*,that front one looks like an ankle buster.

[lakeside53]

yes.. but not my page


Lift the motor first (not to heavy..); the rest of the top section is quite light - all aluminum alloy.

[nheng]

Lew, You may be light years beyond this but just thought I'd throw it out as it has bitten me before.

The set screws that retain the bushings are doubled up. The outer screw (I seem to recall) is a hollow hex and should be removed by limiting your hex wrench travel into the socket. After removing this lock or grub screw, you have access to the actual set screw that retains the bushing. I think numbers 251 and 350 are an example of this.

Den

[Lew Hartswick]

Thanks folks. As to the clamping set screws, Yes those are out OK
no problem. I guess I'll just have to "bite the bullet" and take the
top end off. Turning the head 180 and using the table to support it
sound like a winner. I have hever had the top end off so wasn't sure
if it all drops in one peice or if there was complications. :-)
If the only connection is a "gear mesh" then it would work fine.
All the spindle lub will run out of the oil cups but that won't add much
to the mess already all over the place. :-) I sure wish the ME had
though a bit about service to that area when designing it.
...lew...ps of course those bushings are "frozen" in also they have
green corosion on them. :-(

[lakeside53]

The lower bushing may be damaged by removal - just buy another.. not expensive.


I normally leave the head vertical, take off the motor, then the aluminum pulley section, then the next level (three nuts). The motor weights the most but isn't that difficult You are likely going to want to clean and inspect the pulley sections anyhow.

[EVguru]

I've just done this job on a Bridgeport clone (Long Chang First).

I wound the head through 90 degrees, then turned the belt housing so it hung down and brought the table up to support it. I could then pull the assembly off sideways. In my case it stuck and I had to stone some burrs off the end of the quill spline.