Well armed with advice from FOG experts, I embarked
on rebuilding my router spindle. I had acquired it used and it
ran very hot and had a tinny sound. Suspecting that bearings are
shot, I decided to replace them. For starters this is what
the?spindle looks like and the first job is to remove the
spanner nut holding the bottom bearing assembly. It is the brass
colored thing in the pic below.
I am sure one can buy a proper socket but most I saw
online were for a specific task. Not only were they
expensive,?they also?did?not provide the?detailed dimensions
of features. I was not sure if I would find one that met all
specifications so I decided to just make one. 1-5/16" 12
point socket was the best candidate. Be aware that you may
only find sockets that take a 3/4" wrench in this?size. It
took about an hour to?make it, which included final?grinding
of pin?sides and pin thickness for proper?fit, so not too
bad.
Following is the process I used. I scribed a line from
the socket?end 9mm down around the circumference - depth of
pins. Then I cut painters tape in 5mm width and placed it in
line of the inside hollow of one of the 12 point, then up
and over the end to the outside. This created the shape of
the pin I needed. Then repeated the same thing 3 more times
skipping 2 hollows. The 12 point socket made it really easy
to locate the pins at 90 deg to each other. Using grinder
with cuttoff?wheel, I cut on each side of the blue tape to
the scribe line and then along the scribe line between pins.
The cutoff wheel was too large to complete this cut without
cutting into the pins so I finished with dremel. Finally, I
needed to grind the inside high spots between 12 points as
shown in pic above (red lines).
Various attempts failed to secure the spindle in my vise
(6" long jaws), where it would not turn while attempting to
remove the?spanner nut. I even wrapped an old bike tube
around the two collars. I was told that I needed proper jaws
instead of my homemade wood liners but in the end the method
my neighbor came up with worked like a charm. He cut steel
bar that would fit in the slots of the lower collar but was
wider than the slot depth. Vise just clamped onto these
steel bars and that worked. Here are a few pics of my failed
attempts?and a facsimile?of how it was successfully held -
just imagine the right pic upside down. Also the 8" long
jaws of neighbor's vice allowed for the spindle to be held
vertically on one end of the vice jaws without interfering
with the vice itself. We had to use an impact wrench?to get
the?spanner nut loose.
Next step was to loosen?the top nut. I could not find a
spanner wrench specifically for 44mm - McMaster offerings skip
43-44mm but does offer one for 1 3/4" with a pin, not hook. So
I purchased the set shown below and the smallest wrench is for
38-42mm. I first tried a dead blow hammer but no luck. My
neighbor had a pipe that went over the wrench and with all my
might it came loose.
If you did not know, the bearings on the router spindle
reside in a casing. It was recommended that I get bearings
with C3 clearance because, I think, the concern is that the
shaper spindle casting clamps on the outside of the bearing -
presumably resulting in reduced clearance. While this is true
for the 30mm and 1.25" spindles it is not for the router
spindle. I did get mine with C3 clearance (SKF Explorer
6006-2Z/C3GJN) and I can actually feel the movement in the
bearings, so I hope they will be okay. The bearing I purchased
is shielded - 2Z, on the bearing PN, signifies this. I did
this because they are widely available and the shield can be
removed easily with a pick tool.
However, there can be other?issues buying a shielded
bearing, more on this later.
This bearing has a limiting speed
rating of 17K RPM and reference speed rating of 28K RPM -
this was confirmed by calling SKF as I found conflicting
data on their own websites.?I noted after purchasing the
bearing that it has polyurea grease and contacted SKF to
determine if it is compatible with the lithium complex EP
(Shell Gadus S3 V220C 2) grease I currently use. It is not,
so my choice was to clean it out completely or continue to
service with polyurea grease. I chose to stay with polyurea
as it is supposedly a newer grease that is widely being
accepted for certain applications. I learned a lot with this
exercise. Although I tried to be thorough, the grease was
something I never thought about. This bearing is for motor
application. It is shielded and I believe that is the reason
it came with that specific grease.
Anyhow, old bearings came off
very easily with a puller. So easy that I saw them move while
snugging?up the puller, so I did not need to secure the
spindle in the vice. Oh, bought a 3 pc puller set from harbor
freight for $25 and used the?6" puller.?
?Here
are pics of a bare spindle, new bearing with one shield
removed, bearing case halves and the puller in place to remove
the top bearing.?
I cleaned the bearing surfaces on the shaft with maroon
scotch brite and then polished with gray ultra fine. There
were a couple of marks on the upper bearing surface that came
off easily.
I had several options to install the bearings but I chose
to place the shaft in the freezer (0F vs 18F outside)
overnight. I progressively increased the bearing temp to 200F
in the oven. Enlisted my wife to hold the spindle upside down
and I installed the bottom bearing. It seated with aplomb - no
drama,?quite a satisfying?experience. I had placed both
bearings in the oven and was concerned about leaving the 2nd
bearing in for too long (likely unfounded concern), so I tried
placing the top bearing after the spindle was in the freezer
for 45 mins. I noted that the bearing inner race was touching
the threads on the spindle as I lowered it. Well it went in a
little and got stuck. Earlier, I had asked my friend to drop
his bearing press as a backup, so I proceeded to remove the
bearing with the puller and then installed it using the press.
It went super easy and after this experience, I would use the
press versus messing with hot/cold, unless the application
called for it. I guess I will never know if the top bearing
would have gone in had I cooled the spindle thoroughly. Below
are?pics showing the bearing being pressed. BTW, the shaper
spacer rings work well for pressing on top of the bearing -
grease zerks not yet installed to provide clearance for the
spacer rings. Pic of spindle with bearings installed. Finally,
a close up of the assembled bearing case showing that there is
about 3/16" space for the grease to escape.
I decided to replace the top and bottom locknuts. Top
locknut was damaged due to my exuberant hammering (I think
still usable). Bottom one was okay but was under $5 so might
as well. Felder only had the bottom one in stock so will be a
month before I see it. If there is any significant learning or
update I will add to this thread. I hope anyone needing to do
this in future will find this info useful. Should more info be
desired, I have added links to FOG threads where I asked for
advice on this process.
Imran
