I have a 1hp tefc baldor motor on a grinding machine that operates with the motor shaft vertical and the fan on top. While trying to find the cause of inaccuracy I noticed that the shaft was free to move in and out of the motor a little less than .100 but that from side to side there was no play. Is this something I can adjust myself ( I put new ball bearings in a couple years ago) or am I looking at digging deeper for a new motor.
How would I go about taking this slop out and if parts are involved what would I need?
It sounds like it is missing the spring washer that takes up the slack in the end bell of the motor. These are often used in motor bearing housings when ball bearings are used to reduce the movement of the shaft in or out, but they allow the bearing to move in the bearing housing when the rotor and shaft temperature increases and the shaft gets longer. You can look on McMaster's website and search for spring washer.
Motor shafts aren't usually considered to be good for grinding arbors where axial movement is critical to the grinding operation (thermal expansion, balance and bearing tolerance issues, for example). These issues aren't as significant where grinding takes place on the edge of a grinding wheel, such as a bench grinder.
You might start by examining the motor specs provided by the manufacturer to see if your motor model/series is intended to be used in vertical mounting applications (many aren't).
Common bearings are intended to support radial (side) loads, although certain bearing types are designed to accept axial loading.
Some motor cases will include an internal bearing retainer plate for the shaft end. This type of bearing mount (with a properly designed bearing), will hold the motor shaft securely within the bearing's axial specification, when the bearing is pressed onto the rotor shaft. If the bearing-to-shaft fit isn't fixed (pressed or loktite secured), then the rotor/shaft will still drift.
The tail/opposite end bearing should also be secure to the shaft, but free to creep with thermal cycles of expansion/contraction of the rotor materials. The tail bearing recess should include a wave/spring washer in the end bell cavity, as recommended in another response.
With the proper bearing and a motor case that includes a retainer plate, the axial movement should be limited to an acceptable (or at least predictable) tolerance.
WB metalwork> I have a 1hp tefc baldor motor on a grinding machine that operates with
Thanks Bill, I had no clue about fixing the lower bearing in place with loctite. When I installed the new bearings I warmed them on a light bulb and quickly slid them in place. The old ones may have been a bit tighter than that- I wasn't so observant as I was thrilled that I could put 16$ worth of bearings in and not have to buy a new motor.
OK so when I dis-assemble the motor I will loctite the lower bear> Motor shafts aren't usually considered to be good for grinding arbors
I wasn't recommending that the bearing be secured in the shaft end bell with loctite, but that should work OK. I was suggesting that the bearing on the shaft end should be fixed to the shaft, either by a secure press fit (or shrunk, as you had installed it), or secured with loctite if the fit wasn't tight.
The shaft end bearing retainer plate I mentioned isn't a common feature in motors, although I've seen them used in some industrial-type motors and woodworking routers. If you can modify the shaft end bell to include a retainer plate, this would make future bearing replacements easier. Many motor end bells (not including cheap appliance motors) will have additional features cast into the end bell, although the features aren't used for every motor model of a particular series. The retainer plate goes between the bearing and the rotor, placing it on the shaft before the bearing is installed.
You might see 2 or 3 bosses in the casting around the bearing area which could be drilled to clear screw threads. Fabricating a retainer plate wouldn't be very complicated (heavy gage sheetmetal with tapped holes to accept the screws), and would be certain to securely capture/hold the bearing in a fixed position. This would make future bearing replacements easier, avoiding the need to heat the end bell to release the loctite. If the bearing is secure on the shaft, and loctited to the end bell, this will complicate disassembly for future servicing. The bearing retainer plate will release the bearing from the end bell, which will greatly simplify bearing replacement, and eliminate the need (or temptation) to apply any force to the end bell.
WB metalwork> Thanks Bill, I had no clue about fixing the lower bearing in place with > loctite.
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