Ok, so I went out to the shed and pulled the bearings on an older fat
motor armature. Here are some thoughts:
1) The screw to take off the blade hub (hat) needs to be a 2 inch, 7/16
thread socket head screw. ACE hardware stores have 1.5 inch steel and 2
inch stainless. Get the 2 inch one.
2) When screwing it in you should be able to go 10 full turns. Note that
although the hole is threaded the blade bolts didn't really go in far,
so most of the thread in there is crapped. Might want to clear it with a
thread cutter, just don't break the thread cutter off in the hole or
that's probably that.
3) I went in 5 turns with my bolt before it got tough to turn on my
motor (another spare I had went in 10) which I figured was "good
enough". In my case it was.
4) The bearing puller set Dean posted is what I have, it's great, when
you hook it up to pull the hub remember not to tighten it so tight it
grips the shaft. Use the big puller for all work, there are reasons.
5) Put some grease on the head of the bolt so the puller can turn easier
against it. Wheel bearing grease is always nice to have.
6) Turn, wait, turn a bit more. Slow. It will eventually come.
7) Removing the bottom bearing from the bottom of the motor housing case
is a pain. It should not be that tight.
8) When removing the bottom bearing do NOT try to grip the bearing from
the inside race. Doing so risks nicking or cutting the armature wires
down there especially if the factory bearing was driven too far and
popped the circlip
9) Speaking of which make sure the circlip is proper on the motor shaft.
Sometimes it's bashed back.
10) Pull the bearing slowly, you don't need the bolt once the blade hub
is off.
11) I clean up the shaft with a wire brush on the grinder to get rid of
the crud, and put on the new bearing with a tiny bit of grease on the
inside and tapping it on with a socket plus wood buffer plus hammer
that's just the size of the inner race. Don't pound it too far, just to
the point where it touches the circlip. You can go too far and drive the
circlip down, then you have to pull it and start over.
12) Top bearing is easy to replace, just needs to be put on flush with
the shaft.
13) I put a thin bit of anti-seize on the new hub just so in 50 years
someone will try to remove it and go "wow this was simple. Thank you old
man from 50 years ago!"
Now I need to find a fat motor top and assemble this with the shattered
magnet to see if/how it works. Then pull the new thin motor so I can get
the hub off of it, then the armature out, then take a look at what I can
do to press the high commutator bars back down....
Never dull. Glad I have a stash of bearings, the old ones are really in
pretty sad shape. New ones are so nice and quiet....
C
On 4/20/2024 4:38 PM, metman glasgow-ky com wrote:
I use a socket head cap screw that is long enough to go all the way to
the bottom of the threaded hole in the armature and still stick out at
least an inch from the flange.
Using that style of bolt/screw will essentially provide a "center" for
the point of the puller to stay centered.
Just make sure that you grab hold of the smaller diameter of the blade
clutch (hat) and not the larger flange diameter. The flange and the
hub are brazed together and you can either bend or break the flange
loose from the hub if you pull on the flange.
Someplace I've got pictures of this process, but right now I can't
find them in my files. Let alone remember how to upload them here.
Mike Wallace
Glasgow, KY
270-404-0511
On 2024/04/20 2:12 pm, Christopher Zach via Elec-trak wrote:
While we're on the subject of motors, I forgot:
How does one find a bolt that will allow the hat to be pulled from
the motor shaft?
I have bearing pullers and I know you can't press against the end of
the blade hat: You have to press against something that goes into
that threaded end (preferably to the end so it doesn't shear the
threads) But what kind and size bolt do you use that allows the
bearing puller to have something to center on and not crush it
sideways immediately?
I used to just cut the thing off, but with the limited number of
parts I'd prefer to do it the more "right" way.
Also is there a mail order motor repair service that can rewind the
tall thin mower motor armatures? What kind of info would you give
them to do it?
Thanks!
C
_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak
_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak