mnjim

mnjim · Post by **mnjim** » Sat Feb 05, 2011 2:25 pm

Squealing noise

I have a 1982 Mark V 510 that makes a high pitched squealing noise, especially at low speeds. I have run the motor with the belt off and can't detect any bearing noise from that source. I found that the small bearing in the outer belt sheave seemed warn when I had the power head apart, so I replaced the outer sheave thinking that this was the source of my noise problem. Unfortunately, I still have the high-pitched squealing noise, which is most noticable at low speeds. I can't seem to isolate the point of origin of the noise with my stethoscope, so I'm wondering what the next logical step would be. Should I replace the quill or quill bearings? Is this something that I would need to have a machine shop do? I'm going deaf from this terrible noise.

billmayo · Post by **billmayo** » Sat Feb 05, 2011 3:24 pm

mnjim wrote:I have a 1982 Mark V 510 that makes a high pitched squealing noise, especially at low speeds. I have run the motor with the belt off and can't detect any bearing noise from that source. I found that the small bearing in the outer belt sheave seemed warn when I had the power head apart, so I replaced the outer sheave thinking that this was the source of my noise problem. Unfortunately, I still have the high-pitched squealing noise, which is most noticable at low speeds. I can't seem to isolate the point of origin of the noise with my stethoscope, so I'm wondering what the next logical step would be. Should I replace the quill or quill bearings? Is this something that I would need to have a machine shop do? I'm going deaf from this terrible noise.

I have been able to locate most squealing or noisey bearing by using a stethoscope. I have found that a motor bearing can make a squealing noise when the motor belt is connected and no noise when the belt is removed. With the motor belt removed, how long does the motor continue to rotate after power is turned off. Normally if it takes 3 sec. to 20 sec. for the motor to stop, I find the motor bearings are OK. The next place to "Easter Egg" would be to remove the quill housing and operate the headstock. If the squealing is still present, then the drive sleeve is removed and it's bearings checked. I find that most squealing bearings can be felt with your finger(s) near each bearing (rough, clicks, hard to turn) while manually turning the quill shaft.

mnjim · Post by **mnjim** » Sat Feb 05, 2011 3:31 pm

Thanks, Bill. I will follow your diagnostic sequence and let you know how things play out.

Jim

robinson46176 · Post by **robinson46176** » Sat Feb 05, 2011 4:28 pm

billmayo wrote:I have been able to locate most squealing or noisey bearing by using a stethoscope. I have found that a motor bearing can make a squealing noise when the motor belt is connected and no noise when the belt is removed. With the motor belt removed, how long does the motor continue to rotate after power is turned off. Normally if it takes 3 sec. to 20 sec. for the motor to stop, I find the motor bearings are OK. The next place to "Easter Egg" would be to remove the quill housing and operate the headstock. If the squealing is still present, then the drive sleeve is removed and it's bearings checked. I find that most squealing bearings can be felt with your finger(s) near each bearing (rough, clicks, hard to turn) while manually turning the quill shaft.

I always tell people to "begin at the beginning"... That is exactly what you are doing here except for that one first step you left out.
"Always know where the cat is"...

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Squealing diagnostics