Shopsmith Forums

I have a Mark V from 1982. Bought it used from a friend in 1987. I have used it a lot and never had an issue with it until now. I haven't used it a lot in the last three years because of my job hours, but I have a new job and I anticipate that I'll be able to start working with wood again.

I have a high squeal sound that seems to come on after about a minute of run time. Seems to be normal at high speed but notice it when reducing speed through very specific speeds (specific harmonics of some critical speed?) then seems to come on permanently and be pronounced (and worst) at the lowest speed.

I read several posts from this forum and lubricated the control mechanism and moving sheaves. Actually everything was clean and nothing appeared to be stuck. Everything moved freely. Lubricated anyway and also dressed the belt as recommended on this forum. Also blew out any dust with compressed air with the motor running. Didn't fundamentally change the sound.

Took a mechanic's stethoscope and listened. Even though I originally thought the squeal was coming from the quill area it appears the the squeal is extremely loud when touching the probe to the front plate of the motor (next to the sheave). Can't hear the squeal anywhere else. Based on what I have been reading here I think this means that the bearings in the motor are bad. The motor spins ok by hand w/o the belt but only continues to rotate for about a second. Bumping the motor with power and the belt disconnected it takes 10 seconds or more to coast to a stop.

I also noticed with the stethoscope that I also had a random very infrequent, very low volume (you wouldn't hear it w/o the stethiscope) "flowing marble sound" from the quill area. Kind of like catching up on some mechanical slop every now and then.

So....

1. Do you agree that the motor bearings need replacement?
2. How hard is it to replace these bearings? I am a pretty competent mechanic, already have a small puller, and have rebuilt many alternators in my time. Anything tricky or difficult about this?
3. Do I need to worry about the quill? If so what should I do; replace the bearings here too? Or is a general rebuild with new bearings appropriate if I am replacing the motor and quill bearings?

Any advice would be appreciated.

Dave

[quote="dave99"]I have a Mark V from 1982. Bought it used from a friend in 1987. I have used it a lot and never had an issue with it until now. I haven't used it a lot in the last three years because of my job hours, but I have a new job and I anticipate that I'll be able to start working with wood again.

I have a high squeal sound that seems to come on after about a minute of run time. Seems to be normal at high speed but notice it when reducing speed through very specific speeds (specific harmonics of some critical speed?) then seems to come on permanently and be pronounced (and worst) at the lowest speed.

I read several posts from this forum and lubricated the control mechanism and moving sheaves. Actually everything was clean and nothing appeared to be stuck. Everything moved freely. Lubricated anyway and also dressed the belt as recommended on this forum. Also blew out any dust with compressed air with the motor running. Didn't fundamentally change the sound.

Took a mechanic's stethoscope and listened. Even though I originally thought the squeal was coming from the quill area it appears the the squeal is extremely loud when touching the probe to the front plate of the motor (next to the sheave). Can't hear the squeal anywhere else. Based on what I have been reading here I think this means that the bearings in the motor are bad. The motor spins ok by hand w/o the belt but only continues to rotate for about a second. Bumping the motor with power and the belt disconnected it takes 10 seconds or more to coast to a stop.

I also noticed with the stethoscope that I also had a random very infrequent, very low volume (you wouldn't hear it w/o the stethiscope) "flowing marble sound" from the quill area. Kind of like catching up on some mechanical slop every now and then.

So....

1. Do you agree that the motor bearings need replacement?
2. How hard is it to replace these bearings? I am a pretty competent mechanic, already have a small puller, and have rebuilt many alternators in my time. Anything tricky or difficult about this?
3. Do I need to worry about the quill? If so what should I do]
1) Yes It appears that way.

2) Methinks you can handle the bearing part. Worst part is that gotcha spring on the motor shaft. Need to be careful of the electrical parts when taking apart/reassembling. A pilot bearing puller may be needed for the rear bearing removal.

3) If you couldn't hear the quill noise without the stethoscope, pretend you never heard it! If not replace also. However the noise may be from upstream the power train. The bearings will vary depending on which 'version' you have.

The motor bearings will vary with the motor brand. If an Emerson, the rear bearing may have a 5/8" id. Otherwise they are 17x40x12mm.

I had a high pitched sound just like what you're describing in my old greenie. I couldn't isolate it but it did have that "harmonic" sound about it. It turned out to be the drive belt and disappeared completely when I replaced it with a new link style belt.

The motor isn't completely silent when run without the belt (may be fan noise) but certainly doesn't have any squeal or screeching and didn't appear to be binding in any way.

The motor isn't completely silent when run without the belt (may be fan noise) but certainly doesn't have any squeal or screeching.

Looking at the parts diagram the drive belt is the lower belt in the motor sheaves. It looked like a standard V belt. Is the newer link belt a direct substitution with no mods?

Dave

Did research on the link belt and it lloks like a direct substitution with the 35 links. I also saw reference to an inexpensive Ace Hardware belt for $8 that I may just try for troubleshooting to isolate the problem and it doesn't sound like it would harm the machine for a short period keeping the speed control out of the extremes.

One of Bill Mayo's post also referred to a crush washer between the sheeve and the motor. I did notice today when I was looking that the motor sheave had very little clearance between the sheave and the motor housing. I didn't try to measure it but it was very close. So I am going to check that tomorrow. Anybody know what a typical clearance is between the inner motor sheave and the housing? 0.010 in? 0.020 in?

The original owner never did anything to this machine and this is the first time I have had the cover off so I know that the sheaves haven't been "popped" as Bill warns that could loosen the sheave set screw.... Has anybody experienced them coming loose just through normal wear? Either way it sounds like I am going to have to remove the drive sheave from the motor to narrow it down once I eliminate the drive belt as the source.

Dave

shipwright wrote:I had a high pitched sound just like what you're describing in my old greenie. I couldn't isolate it but it did have that "harmonic" sound about it. It turned out to be the drive belt and disappeared completely when I replaced it with a new link style belt.

I find "Belt Conditioner" (auto parts store) does wonders for any V belt. The motor belt can cause weird sounds from the Shopsmith headstock.

I use 35 links for the link belts I use on my headstocks but did notice some aluminum dust in the motor pan after several years of use. It did keep the sheaves vanes shiney and helped reduce vibrations. I recommend the Shopsmith belts as they are normally a little wider than 1/2" belts and the proper length (26 1/2"). You may need to do the "High Speed Adjustment" when changing belts to position the belt at SLOW and FAST speeds. Belt should be about 1/16" below the sheaves outter edge.

Here's some sound advice! (pun intended)

Before you start messing around with bearings and stuff - try a simple fix. Sometimes the little fan sheave spacer gets a little worn and allows the fan sheave to touch on the motor housing and make rubbing/scraping/squealing noises. You will have to remove the spring and both sheaves to see if there is a problem here.

dave99 wrote:Did research on the link belt and it lloks like a direct substitution with the 35 links. I also saw reference to an inexpensive Ace Hardware belt for $8 that I may just try for troubleshooting to isolate the problem and it doesn't sound like it would harm the machine for a short period keeping the speed control out of the extremes.

One of Bill Mayo's post also referred to a crush washer between the sheeve and the motor. I did notice today when I was looking that the motor sheave had very little clearance between the sheave and the motor housing. I didn't try to measure it but it was very close. So I am going to check that tomorrow. Anybody know what a typical clearance is between the inner motor sheave and the housing? 0.010 in? 0.020 in?

The original owner never did anything to this machine and this is the first time I have had the cover off so I know that the sheaves haven't been "popped" as Bill warns that could loosen the sheave set screw.... Has anybody experienced them coming loose just through normal wear? Either way it sounds like I am going to have to remove the drive sheave from the motor to narrow it down once I eliminate the drive belt as the source.

Dave

Yes, I still find a few Fan Sheave set screws are loose or missing. In fact I have a few fan sheaves and motor rotors with badly grooved shafts from a loose or missing set screw. It is a spacer (.4") between the fan sheave and front motor bearing, not a crush washer. This very thin spacer (.028") will cut into the fan sheave hub if the set screw is not tight. Shopsmith has increased the wall thickness (.052") of this spacer that helps prevent this problem now.

I pull the fan sheave if the clearance is less than 1/16" between the fan sheave and the motor housing plate and check the parts. It can be as much as 3/16" clearance with no problems.

What about the idle shaft eccentric bushing? Is the poly-v belt tensioned correctly? I once spoke with shopsmith about a similar harmonic sound coming from my shopsmith. They refered me to a service bulletin in the manual on how to adjust the eccentric to the proper tension. If you can push the belt more that 1/8" when applying heavy pressure, the belt needs to be tensioned. In my owners manual from 1988 the instructions are titled Checking Belt Tension. Page 55. Hope this helps. It is also a maintenance point for every 10 hours of running time.

Based on the above, I am sure that the sheave has moved too close to the motor housing. I certainly don't have a 16th of an inch clearance. So either the set screw is loose, the washer is damaged, or both.

I had already put dressing on the belts.

My owner's manual from 1982 only goes up to page 21..... and includes no routine maintenance for checking belts... only oiling. A separate addendum sheet included with the manual gives the procedure for installing the poly-v belt and specifies a 1/4" deflection. I'll check it again but based on what I remember yesterday it had a nominal amount of deflection and my thought is that it is ok. Using the stethoscope the areas around the poly-v bely were very quiet.