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I used NTN 6203 LLB

They were close to $20 each from grainger. The motor was much quieter than I expected it to be, but I don't know how valuable it would be to try and make your motor quieter. I say this because the motor may be silent, but the headstock won't be. I used the same type of bearings in my headstock (different size but same design and brand) and I have yet to reassemble everything. Who knows, maybe the luck I had with lack of motor noise will carry into the headstock and I'll get a quiet headstock. We can dream right?

joshh wrote:I used NTN 6203 LLB

They were close to $20 each from grainger. The motor was much quieter than I expected it to be, but I don't know how valuable it would be to try and make your motor quieter. I say this because the motor may be silent, but the headstock won't be. I used the same type of bearings in my headstock (different size but same design and brand) and I have yet to reassemble everything. Who knows, maybe the luck I had with lack of motor noise will carry into the headstock and I'll get a quiet headstock. We can dream right?

Wishful thinking for sure!;) Reeves is de culprit!!!!

It was a sunny day until evening, so only a couple of hours to work on it today. I reassembled everything into the headstock, used the sanding disc to rotate while putting the speed back to low, then turned it on. At slowest speed, I measured 88dB of noise, operating in the vertical drill press orientation.

Then I started to increase the speed, but by the time I got to E or so I got such a horrible buzzing/knocking sound that I turned it off. I reset the speed down to Slow, but still it persisted (turned on for about 5 seconds). So I pulled the belt off the motor and tried again, same thing. But I noticed that that motor went all the way up to speed, and after turning off power, coasted down without any noise (except the normal fan/bearing noise and click of the centrifugal switch).

Now I have taken the motor off completely again, as well as the sheaves, and the noise is much less, but there is a slight buzz, which I am pretty sure is 50Hz. I'm tired now (10PM here), so I haven't opened the motor to see if any stray screw hasn't gotten somehow inside and is causing this vibration.

Aside from this new mystery, the noise level assembled into the headstock is tolerable, since anyway I'll need to wear hearing protection when cutting, etc. so I'll just get used to always wearing it.

Joshh, let us know how all the new bearings affect overall noise. For now I'm leaving the rest of the bearings alone, since they seem relatively new and good.

Check to see that the fan sheave is not clanging into the motor housing. There is a short spacer that holds the fan sheave out away from the motor housing. There have been instances when this spacer was too thin and wore itself into back of the fan sheave thus decreasing the clearance. Also the fan sheave set screw coming loose can cause this by rattling on the motor shaft. The set screw MUST also secure the key in the shaft keyway. It really needs to be torqued tight!

A little bit if blue Loctite on the setscrew will help also.
In addition, did you miss the wavy washer that is supposed to go in the closed end of the motor housing? If the washer is missing then a vibration will happen.
Bill V

Just a hint. I found the link belt did help reduce the noise and vibration. It can be a PITA to get the correct belt length. 35 links on the link belts I used. The motor pan is like a drum skin. It does help to increase any small noise. The motor should be very quiet when operating without the belt.

I read through some websites about AC induction motors, and realized that most likely the problem was so-called "soft foot", in this case caused by the mounting feet being out of alignment and causing the rotor inside to be out of balance and thus un-equally affected by the magnetic field.

Very important to make the marks on the motor case to ensure correct alignment!

freedomlives wrote:I read through some websites about AC induction motors, and realized that most likely the problem was so-called "soft foot", in this case caused by the mounting feet being out of alignment and causing the rotor inside to be out of balance and thus un-equally affected by the magnetic field.

Very important to make the marks on the motor case to ensure correct alignment!

See post #4 of this thread

freedomlives wrote:I read through some websites about AC induction motors, and realized that most likely the problem was so-called "soft foot", in this case caused by the mounting feet being out of alignment and causing the rotor inside to be out of balance and thus un-equally affected by the magnetic field.

Very important to make the marks on the motor case to ensure correct alignment!

Interesting!

Considering the mounting of the SS ,motor and pan, I doubt soft foot could occur. The mounting is not rigid by any means and therefore incapable of pulling the bearings out of alignment with the core or the armature.

The importance of aligning the 'marks' between the motor shell and the 'end caps' is to insure the screws retaining the 'end caps' are not cocked(and prone to loosening) and to ensure the holes line up(core and two 'end caps'). That is the way I 'see' it!;)

The ss output shaft is belt connected(soft connection) so other than belt flop nothing would be relevant.

All I know is that after I aligned it (by leaving the long bolts loosened, then screwing the motor down to the mounting plate and turning the ends so the screws lined up) it quit having the afore-mentioned buzzing problem.

In any event, had I carefully followed the instructions above, I never would have had this problem!

I will try some link-belt if I can find any over here. I noticed that the v-belt was sometimes vibrating badly (obviously from sitting for three years). In the meantime I'm going to try to figure out how to say "belt dressing spray" in Slovak...