Re: [CAD_CAM_EDM_DRO] Machinery bone-yards? Need Millport parts

Jon Anderson wrote:

> Pete and Robert,
>
> It's a step pulley head, and I have installed an inverted. (never
> gonna
> buy another VS head!) There's something going on in the pulleys on the
>
> spindle side, if I take the belt off, the motor runs nice and quiet.

You can isolate the trouble fairly easily with all the clutches in the
Bridgeport
J style head. First, disengage the direct clutch. This is the one with
the handle
that rotates around the spindle, up on top, somewhat near the spindle
brake
on the 1J. On the 2J, these are usually connected together with a rod,
and there
is a Hi - N - Low selector somewhere. Put it in Neutral.
Now, with the regular V belt back on, see if you have noise.
If so, it could be the driven cone pulley OR the back gear, as the
spindle
is should not be running, here. If you DO have noise, lift the pulley
housing top
off and remove the toothed belt, then reassemble, and check again.
If so, it is the 2 bearings on the driven cone pulley. They are simple,
but
the mechanism that allows the cone pulley/clutch teeth to move
vertically
has a spring in it, and some delicate pegs that ride the cam that raises

it. Also, this mechanism is somewhat connected to the spindle brake.
But, you should be able to do the entire repair in half an hour.

If this doesn't demonstrate the noise, then it must be in the back gear.

My experience (sample of one!) is the back gear bearings are in
the worst shape in the whole head! But, once you have the belt
housing off, it is quite easy to open up and inspect the back gear.
There are about 10 small screws (8-32?) that hold a thin plate
on top of the base of the belt housing. Lift this plate carefully, as
it holds 2 bearings. Everything is pretty much out in the open, now,
so lift out the gears and inspect the lower bearings. Remove any
escaped balls and crunched bearing shields, and any other
debris in this housing. I don't know what to lube this with. The
machine appears to have an oil cup especially for this, but some
people say to grease this section of the machine.

Well, if the trouble doesn't show up in one of these two areas, then
it is time for the bad news. It's the spindle bearings! You didn't
want to hear that, I know! Final confirmation can be had by
spinning the spindle while listening (with all other machines
in the area turned off). A new bearing set is practically silent
at any speed you can get by flipping the spindle with your hand.
And, I do mean REALLY silent, like you'd almost need a
stethoscope to hear it. Mine sure aren't that quiet anymore.
The spindle bearings are another story completely, and cost a
lot more than the cheap bearings above.

Of course, all the above tests should be done with the 'feed worm'
disengaged. This is the little crank on the upper right front of
the main head casting (on a real Bpt). It drives the power feed.
But, it is unlikely the feed worm and power feed drive is the source
of the noise, as it all turns pretty slowly.

Good luck,

Jon