I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X axis
and have had trouble since. My table has been binding in the X direction on
occasion, and today (after not using the mill for months) I checked and the
powerfeed isn't even working - the pinion and ring gear don't even mesh. I
took it apart and I don't understand what I'm seeing. There are shims that go
in there, and all of a sudden my shims aren't bearing between mating surfaces.
The table lead screw looks like it somehow got shoved too far to the right,
so there is a tapered shoulder that the shims should mate to instead of a nice
square shoulder.

I really don't understand how the X lead screw is located axially. There are
opposing bearings on each end which it slips through, and apparently the
whole business is snugged up only by the handle nut.

Can anyone enlighten me?

Grant

On Sun, 04 Nov 2007 15:53:03 -0800, Grant Erwin
wrote:

I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X axis
and have had trouble since. My table has been binding in the X direction on
occasion, and today (after not using the mill for months) I checked and the
powerfeed isn't even working - the pinion and ring gear don't even mesh. I
took it apart and I don't understand what I'm seeing. There are shims that go
in there, and all of a sudden my shims aren't bearing between mating surfaces.
The table lead screw looks like it somehow got shoved too far to the right,
so there is a tapered shoulder that the shims should mate to instead of a nice
square shoulder.

I really don't understand how the X lead screw is located axially. There are
opposing bearings on each end which it slips through, and apparently the
whole business is snugged up only by the handle nut.


There's a pair of bearings on the left end that are preloaded by the
handle and maintain the axial position of the screw. The screw is
supported, but free to move axially, by a single bearing on the right.
I had problems with the Servo feed on my Supermax mill which were
similar to what you're seeing. I figured out a fix by studying the
installation drawings for the power feed, but as I recall, a proper
Bridgeport installation shouldn't suffer from the problem I found with
my machine.

If you think the screw is moving axially with the left end support
assembled, there's something wrong there, and I'd dig into that end
before fussing with the feed.

--
Ned Simmons

"Grant Erwin" wrote in message
...
I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X
axis
and have had trouble since. My table has been binding in the X direction
on
occasion, and today (after not using the mill for months) I checked and
the
powerfeed isn't even working - the pinion and ring gear don't even mesh. I
took it apart and I don't understand what I'm seeing. There are shims that
go
in there, and all of a sudden my shims aren't bearing between mating
surfaces.
The table lead screw looks like it somehow got shoved too far to the
right,
so there is a tapered shoulder that the shims should mate to instead of a
nice
square shoulder.

I really don't understand how the X lead screw is located axially. There
are opposing bearings on each end which it slips through, and apparently
the
whole business is snugged up only by the handle nut.

Can anyone enlighten me?

Grant

It's trial and error with the ship-pack.

On Nov 4, 3:53 pm, Grant Erwin wrote:
I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X axis
and have had trouble since. My table has been binding in the X direction on
occasion, and today (after not using the mill for months) I checked and the
powerfeed isn't even working - the pinion and ring gear don't even mesh. I
took it apart and I don't understand what I'm seeing. There are shims that go
in there, and all of a sudden my shims aren't bearing between mating surfaces.
The table lead screw looks like it somehow got shoved too far to the right,
so there is a tapered shoulder that the shims should mate to instead of a nice
square shoulder.

I really don't understand how the X lead screw is located axially. There are
opposing bearings on each end which it slips through, and apparently the
whole business is snugged up only by the handle nut.

Can anyone enlighten me?

Grant

The previous owner of my Excello installed the table powerfeed
incorrectly by drilling and pinning the gear to the shaft about 1/4"
too far to the right (IE the leadscrew is translated approximately
1/4" from where it should be). This means that the non-powerfeed
handwheel has ~4 threads holding it in place, and that careful
adjustment is necessary to avoid binding. When I first got the
machine, I had to readjust it 2-3 times a day, every day, but now
(almost 4 years out), it seems to work fine.

--FWIW I took the Servo drive off of my mill a while back and it's
now rusting away in the back of the truck. Been rained on a couple of times
but it's cheap if anyone wants it.. Decided my '70s vintage controller was
better than the '90s vintage 'replacement'. $4k down the toilet, sigh...

--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Andy Philbrick?
www.nmpproducts.com
---Decks a-wash in a sea of words---

On Nov 4, 3:53 pm, Grant Erwin wrote:
I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X axis
and have had trouble since. My table has been binding in the X direction on
occasion, and today (after not using the mill for months) I checked and the
powerfeed isn't even working - the pinion and ring gear don't even mesh. I
took it apart and I don't understand what I'm seeing. There are shims that go
in there, and all of a sudden my shims aren't bearing between mating surfaces.
The table lead screw looks like it somehow got shoved too far to the right,
so there is a tapered shoulder that the shims should mate to instead of a nice
square shoulder.

I really don't understand how the X lead screw is located axially. There are
opposing bearings on each end which it slips through, and apparently the
whole business is snugged up only by the handle nut.

Can anyone enlighten me?

Grant

The previous owner of my Excello installed the table powerfeed
incorrectly by drilling and pinning the gear to the shaft about 1/4"
too far to the right (IE the leadscrew is translated approximately
1/4" from where it should be). This means that the non-powerfeed
handwheel has ~4 threads holding it in place, and that careful
adjustment is necessary to avoid binding. When I first got the
machine, I had to readjust it 2-3 times a day, every day, but now
(almost 4 years out), it seems to work fine.