I am in the middle of a top-end rebuild on my R2E4. It was making
excessive noise, and it turns out that a pulley bushing failed, galling
the motor shaft, and chipping out the key slot in the pulley.
Both the motor shaft and movable pulley half on the Vari-Speed drive
element must be replaced.
I have obtained the proper parts, and have the machine apart. In the
midst of this, I developed some "tricks" or strategies to get the motor
off without removing the head -- at least not removing it "completely".
Since this is (according to Hardinge) "impossible", I'm putting together
a photo-essay on how to do the whole thing without removing the head, and
FWIW, under an 8-foot ceiling. It's been tricky, but a little luck and
some ingenuity have panned out.
Ignoramus7592 fired this volley in
Barry the owner, Nicole the office/sales woman, and Heather the tech (who
rebuilds mills herself... no comments, guys) are extremely helpful,
friendly, and ready to answer calls.
They'd not encountered some of the problems I have, because most of their
business is mostly rebuilding Series I and Series II manual machines.
But they had all the right parts ready, and shipped them for quick
The only thing they didn't have was a method of removing the motor
without removing the head -- which, is, after all, "impossible". Got
This is the one which has the motor under the extension of the
head, instead of on top of it? Easier to get *off* with poor clearance,
but really nasty to get back in place.
One of the tricks which I remember is to take some channel and
drill it for one of the bolts which hold the halves of the housing
together (which happens to also fit a tapped hole in the end of the
motor shaft) and use the screw and channel to depress the sliding pulley
so the C-clip on the motor shaft can be removed -- to allow the sliding
half of the pulley to be removed.
I'll be interested in seeing that when you have it done.
I remember finding a place which would happily sell me things
like the pulley halves, the motor rotor with shaft (with the old one
going to them as a core charge) the bushings, and various other things.
However -- it has been perhaps fifteen years since I got them, so I'm
not sure that the company is still around. (I'm also not sure who they
were, but they had a nice exploded view of the heads.)
"DoN. Nichols" fired this volley in
IF not the same company (they were around 15 years ago),
Machinerypartsdepot.com now provides the same services, with the same
happy, helping style and documentation.
I knew about the channel/bolt in the motor shaft, but it was easier to
just put a scissor jack between ceiling and shaft (rather than making
another tool!), and use a large socket as a pressing arbor. Once jacked
down a fraction of an inch, there's a locking screw one can tighten to
prevent the pulley from pushing back against the snap ring.
BTW, Don, the motor is NOT "easier to get out" -- it's WAY harder. On
the "pointing down" manual series I and series II heads, the motor just
lifts up. If you have the clearance (you need about 4"), you can get it
out. On the CNC "pointing up" machines, you have to partially or
completely remove the head and spindle assembly to get the motor out.
Otherwise, it's trapped between the housing pan and the ram of the
machine. Also, the motor shaft is almost twice as long on the CNCs as on
the manual machines, making you have to "snake it out" rather than just
pull it clear. That's why I had to figure the strategy to tip the head
forward without craning it off.
FWIW, I think a head removal "jack" that mounts on the table would have
done OK, too, but then you have to remove two or three lines and cables
that pass through the ram. They are a MF to re-thread. My forearm won't
even pass through the draughts in the ram, so I have to use a long-reach
gripper to get those lines in and out. With my method, nothing needs to
be disconnected except the big AMP-connector cables and air lines to the
brake and spindle speed control motor.
Ignoramus29003 fired this volley in
Then you have a smaller arm than do I. I have "removed" the head, but
kept it captive. I cannot reach inside the ram more than about six
inches to thread things through the holes. I have to use a "reacher"
tool, and that's cumbersome and chancy.
I have no doubt that removing the head would have proved as effective as
what I did, but I (at least) eliminated the removal of the connections
that prove so hard for me to re-route.
Well ... when I got my machine, the motor was in a box packed
alongside it, along with two pulley halves.
The keyway on the motor shaft was badly damaged by the Delrin
jacket on the key in the pulley half having work out along with the
I had to figure out how it went together. I used a lab jack
between the motor and the ram, which provided support.
Mine must have had more clearance. It was a very early CNC
(BOSS-3, with a serial number below "CNC 110", and I was told that they
started with "CNC 100". The logic boards were wire wrapped instead of
full printed circuit boards.
O.K. Different from what I remember.
The only thing which passed through the ram was the oiling line
from the BiJur oiler. The motor power was some oiltight spiral flex
jacket which went into the top of the transformer housing on the back of
the machine, and the FWD/STOP/REV switch and the panic switch were a
different cable which went into the computer box on the side (down low,
I never even thought of running them that way. Maybe worth
considering. Was this the dovetail ram, or the rigid ram -- I know that
both types were used in these machines.
Mine also was too old to have the air motors for the speed
control, and the solenoid for the brake. I plan to have the CNC talking
directly to the VFD to control motor speed, and most of the time can
just leave the variable speed set at one point. (I'm also going to add
a switch to sense the back-gear lever to reverse the FWD and REV
controls on the VFD when it is in back gear, so I don't have to
remember to switch it when changing to back gear.
I'm currently making a replacement motor mount for the Y-axis
motor -- since I am replacing the steppers with servo motors, and the
servo motors are a lot longer, and don't fit in the cavity in the knee
made for the steppers.