What's the normal motor sound when rotating output shaft by hand?

mickyd · Post by **mickyd** » Tue Feb 17, 2009 2:11 am

I have the motor out. When I spin the shaft, it makes a "clickity" sound, same sound when rotating in either direction. (I know your saying what the hecks a clickity sound!!!) Don't know how else to explain it. Since I've never done this rotation test on a motor, I don't know what normal is supposed to sound like. I thought maybe it's the brushes that are making this sound but ????????

There is definately NO PLAY when biasing the output shaft in any direction. It rotates pretty smoothly also.....just don't know about that "clickity" sound.

Any input?

thainglo · Post by **thainglo** » Tue Feb 17, 2009 5:40 am

Mike - I don't recall hearing any sounds when spinning a motor by hand. I have mine out of the headstock, will check it out when I get home and confirm.

bucksaw · Post by **bucksaw** » Tue Feb 17, 2009 10:06 am

mickyd wrote:I have the motor out. When I spin the shaft, it makes a "clickity" sound, same sound when rotating in either direction. (I know your saying what the hecks a clickity sound!!!) Don't know how else to explain it. Since I've never done this rotation test on a motor, I don't know what normal is supposed to sound like. I thought maybe it's the brushes that are making this sound but ????????

There is definately NO PLAY when biasing the output shaft in any direction. It rotates pretty smoothly also.....just don't know about that "clickity" sound.

Any input?

Don't believe you have brushes in the motor. Maybe the contact points? or bearings starting to go?

billmayo · Post by **billmayo** » Tue Feb 17, 2009 12:11 pm

mickyd wrote:I have the motor out. When I spin the shaft, it makes a "clickity" sound, same sound when rotating in either direction. (I know your saying what the hecks a clickity sound!!!) Don't know how else to explain it. Since I've never done this rotation test on a motor, I don't know what normal is supposed to sound like. I thought maybe it's the brushes that are making this sound but ????????

There is definately NO PLAY when biasing the output shaft in any direction. It rotates pretty smoothly also.....just don't know about that "clickity" sound.

Any input?

There are no brushes in any Shopsmith headstock motor. Does the motor operate? Normally a clicking sound is a pitted bearing. I can feel any pitted bearing when turning the shaft. I find the front motor bearing (sheave end) takes all the wear so if the noise is in the motor front end, then it most likely is the front bearing. There should be no real noise when rotating the motor shaft. Does the fan sheave have some clearance (1/16"-1/8") from the front motor plate? Can you hear which motor end has the noise? If from the back end, it may be the centrifugal switch spring being weak or broken.

Before disassembling the motor, mark the end plates and housing so the motor will be reassemblied correctly again. I use a pocket knife or scribe to make a line over one of the bolts holding the motor together.

mickyd · Post by **mickyd** » Tue Feb 17, 2009 2:23 pm

Yes the motor operates. I turned it on ONLY for a split second since the power cord was in such poor condition.

I am going to have to listen and feel a little closer after work. I am not absolutely sure right now if the sound comiong from the front or back. I am glad to hear you say that there should be no real noise. At least I know that indeed I DO have noise that shouldn't be there. It was subtle but load enough to be noticeable

I do have good clearance on the fan sheave. That was the first thing I checked since it was external.

Thanks for the clear guideance and instruction. I'll continue later.

nuhobby · Post by **nuhobby** » Tue Feb 17, 2009 3:11 pm

Hi,

For actual motor bearing problems, it's probably fair to expect them to occur in both rotation directions, as you twist the motor shaft by hand.
However if you only hear the subtle clicking noise in one direction, or shortly after reversing your hand-twisting direction, then it may be a noise from the centrifugal switch. In such case I'm not sure about what constitutes "normal" noise, but if your motor starts OK and runs OK, then that's one indicator toward the good.

beeg · Post by **beeg** » Tue Feb 17, 2009 3:51 pm

mickyd wrote:I turned it on ONLY for a split second since the power cord was in such poor condition.

Don't forget to replace that cord with a 12ga SJT cord or better.

bucksaw · Post by **bucksaw** » Tue Feb 17, 2009 9:01 pm

Read about Centrifugal switches

mickyd · Post by **mickyd** » Thu Feb 19, 2009 12:10 pm

Pulled the motor apart last night and found the source of the noise. The back bearing relieved itself of all its grease and the sound was coming from the dry ball bearings. Oddly (to me anyway), the shaft rotation still felt very smooth.

Anyway, thanks for the info you guys shared. I'll replace the 2 bearings, get an updated power cord and I should be ready to give it a full power test by this weekend.

mickyd · Post by **mickyd** » Fri Feb 20, 2009 1:51 pm

beeg wrote:Don't forget to replace that cord with a 12ga SJT cord or better.

For all of us electrically challenged members, what's the SJT stand for? Does the SS replacement cord meet that because I just brough one?

I searched both Home Depot and Lowes last night for the 12ga SJT but they don't carry. The largest they had was 14ga with no product marking indicating SJT.

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