Grant,
Thanks - that's a big help. I wish I had the discipline to write stuff like
that down when doing this sort of thing. Sure comes in handy later.
Do you remember the approximate cost of the bearings? Motion Industries has
an outlet close by and I'd probably go with them.
My previous contacts with KO Lee were not all that encouraging, but I'll try
Doug.
It appears that the end caps will need a non-standard face spanner (odd hole
size for the pins), but it should be easy enough to cobble up something up
that will work. It sounds like I can remove the end caps without any risk
of damaging the spindle or bearings - is that correct? Taking those off
would let me check to see if the lock nuts are loose, which would be a step
in the right direction.
Good tips in those links as well as the rest of your post.
Good luck on the hard drive - went through a failed HD myself a while back
and it wasn't pretty.
Mike
"Karen Story" wrote in message
...
This is Grant Erwin, posting less frequently these days and from Karen's
account because my PC is waiting for a new hard drive.
I bought a very used KO Lee S612 and the spindle bearings were bad. I
rebuilt my own spindle. The bearings were very expensive. KO Lee specs
Torrington/Fafnir bearings but I got New Hampshire Ball Bearings (NHBB)
instead. I relied extensively on the internal KO Lee documentation. You
should call KO Lee and ask them to speak to someone about how to rebuild
your old spindle. My contact was Doug; 605-225-5820 x175. I wrote up the
procedure I used, and here it is:
-------------
Spindle:
My spindle is No. S655C, which is real old. I'm told it uses 2 sets of
angular contact ball bearings (not tapered) each set of which is Fafnir
2MM9105CRDUME6151. (NOTE: this part number is a K.O. Lee part number from
the early 1950's, and it is not possible to obtain this any more for
several reasons. The current Fafnir part number is 2MM9105WICRDUM, which
is one set. Two sets are needed.)
Removal and Installation:
The bearings are retained by the end caps. The end caps are drilled
for face spanners although special tooling may be needed. (I sometimes
use two Vise-Grip chain wrenches .. don't know if this will work.)
The bearings are supposed to be installed DB (back to back). For
an explanation of that, see below.
The bearings are loaded by the lock nuts inside the end caps. In the
front,
use a very light preload (3-5 inch pounds). In the back, tighten to
3-5 inch pounds and back off 1/8 turn to allow for thermal expansion.
After installing new bearings, check runout of the wheel taper. If
the runout exceeds .0001" (one tenth) the wheel taper needs to be
reground. Note that it may be possible to rotate the bearings in
their seats, to reduce runout, as the high runout points are marked
with an asterisk on one side.
Balancing is not necessary.
The bearings should be greased prior to use. They should be about
1/3 full only. This should be between 1 gram and 1.25 grams of
grease. A suggested grease that is widely available is Chevron SRI.
The design of the end caps should keep out coolant and grinding grit.
Addendum (from talking to Jim Goode @ Torrington/Fafnir in Bellevue,
also from talking to Doug @ K.O. Lee again)
The bearing number I need is Fafnir 2MM9105WICRDUM, which is a set
of 2, I need 2 sets. These should come with the high runout points
marked with an asterisk on one side, and with no grease on them.
Fafnir recommends that from 1.0 gram to 1.25 grams of grease (they
call out Chevron SRI, but others will work) be installed with a
finger, spread around the bearing. Fafnir cautions that the
orientation of angular contact ball bearings in the spindle is
significant. K.O. Lee says that 3 orientations of bearing are
possible: DB, DF, or DT, and that DB is called out in this spindle.
An explanation of these last terms is given in the nice URL:
http://www.ntnamerica.com/Knowledge/...ng_AngCont.htm
another good reference site is:
http://www.mmsonline.com/articles/hsm9802.html
------- end of my old notes
I went to a "tobacco shop" in Seattle's University District and bought
a very inexpensive gram scale to get the correct amount of grease. I
installed the grease using a needle attachment to my grease gun (don't
remember that part very well). I made a custom face spanner and a
lathe-turned bearing drift for this job. My spindle has runout within
spec. I have never been able to get a perfect ground finish with it;
however I rarely am looking for one. My goal is usually sub-thou
parallelism of two flat faces, and this my machine does very well.
I found working with KO Lee to be straightforward and pleasant. I
would not hesitate to try rebuilding your spindle. I should note that
over the succeeding years I have seen several NOS KO Lee grinding
spindle assemblies complete on ebay, and they have often sold for
around $100 which is only about 20% of the cost of a new set of
bearings.
Any small surface grinder should have the very edges of the wheels
eased a little bit with a dressing stone after being trued with a
diamond dresser. This helped me a lot to get a much better finish.
I also often set a smallish part at an angle to the X travel of the
surface grinder, take a pass, then without changing the Z location,
reset the part at an opposite angle and regrind. This gives a
pleasing checkered finish. It's all cosmetic - even a tenths
indicator shows no deflection whatever across the checker marks.
Grant Erwin
Kirkland, Washington
Mike Henry wrote:
I recently set up a used KO Lee S714 surface grinder and was a little
disappointed at the finish, though my experience on these tools leaves a
lot
to be desired. The surface almost seems to have very shallow scallops
at
regular intervals. They can't be felt by hand and a fingernail doesn't
catch
anywhere. There is a bit of noise as the grinder winds up but that
seems to
be coming mostly from the motor. The grinder appears to be in otherwise
very good condition.
I checked the spindle runout with a gage head and amplifier and am
seeing
about 0.00075" with the gage tip on the tapered spindle nose (wheel &
collet
were puulled off and belts between spindle and motor were removed). I
can
also get about 0.0015" deflection in the spindle by manually pushing or
pulling the spindle toward or away from the gage tip. The spindle feels
reasonably cool after running for 45 minutes without a wheel or collet
mounted.
This seems to be pretty far out of spec to me, but opinions would be
appreciated from those that know better than I.
If this does need attention, is there any chance that the bearings just
need
adjustment? There's a circular disk threaded into the outboard side of
the
spindle with holes for a pin spanner wrench. I haven't mucked with that
yet
but presume that it's there to adjust bearing pre-load.
If the bearings need to be replaced what are the chances of being able
to do
this myslef? A manual for a slightly different KO Lee grinder suggests
that
spindles must be returned to the factory for rebuilding.
TIA, Mike