Noise Levels During High Speed Operation

[cdhknives]

Just curious as to what volume I should expect my lathe to generate when running at max speed.

Background: After finishing my spider and replacing the preload collar with the spider, I tightened the prescribed 2 teeth of rotation. I found a deal on a Harbor Freight non contact IR temperature 'gun' and over the weekend ran my lathe in to see about the bearing temperature rise. I have always avoided max RPM operation because A) Never needed it, and B) Don't like running at the extremes of any machinery.

The noise level was quite non-hearing safe. I work in refineries, we take safety classes like most people take meals, and they preach 'if you gotta raise your voice to talk around machinery, it's not hearing safe'! No doubt, this lathe is not hearing safe at 3 paces away running at max (2072) RPM. One notch lower (1270 RPM) is marginal.

My experience with bearings is noise==wear/damage, but my experience is mostly automotive bearings. This lathe has not been babied by any stretch, especially by the original owner that my Grandfather bought it from.

How loud is acceptable? BTW, max T was just over 120F from an ambient T of about 85F.

 

[Mondo]

I would not expect the no-load temperature of the bearings to rise more than a few degrees, certainly not the 35 degrees you are reporting. Even under rough cutting load for a long part I think your temperature rise is excessive. 120°F is quite warm, most plumbing regulations require shower water temperatures to not exceed 112°E. and higher than the permissible temperature for kitchen tap water. Something is too tight or is not getting adequate lubrication.

My opinion is based on my own lathe. I have not made any temperature measurements on my own, but I do not notice anything more than slightly warm. Of course in the below-grade basement of my home the ambient is only about 60 - 65 tops. But even in my former residence where the lathe was in a one-car garage and I often ran it with the overhead door wide open I never noticed any substantial rise. My lathe spindle has Babbitt bearings which may run slightly warmer than rollers.

On to noise: Open spur gears are noisy. Keeping them lubricated can reduce this noise. I am using Lubriplate Open Gear Grease on my change gears. The stuff has the color and consistency of warm licorice. Use of the grease reduced gear noise quite a bit versus using SAE 20 oil. But at maximum operating speed the gears are still noisy.

Set the clearance of change gears such that a slip of paper from a grocery store bag will just fit between them. Make sure the gears do not wobble as they turn. Change the sleeves if necessary. The change gears can be faced off slightly at the outer diameter making the teeth slightly narrower than the gear hub. This will reduce noise generated where the sides of the gears might rub against each other. I would not modify QCGB gears, however.

I hope this helps!

Spiral_Chips

 

[cdhknives]

I should note that this noise level is with the tumbler disengaged. Only the motor, countershaft, and spindle are turning.

 

[Wierd Harold]

I should note that this noise level is with the tumbler disengaged. Only the motor, countershaft, and spindle are turning.

If I run mine at full speed (which I did for the first time for this test) under the same conditions, it is quite quiet. You could easily talk on the phone next to it. My 1/2 inch hand drill and 8 inch grinder are noticeably louder.
WH

 

[pdentrem]

It may help if you could post a sound clip, maybe as a video, to help you out.
Meanwhile, is the sound a clatter or a buzz or a whine? Different sounds represent different possibilities.
Pierre

 

[cdhknives]

It sounds like a higher pitch than gear clatter...I'd call it a bearing whine. Let me see if I can get a decent vid clip with my phone camera. The sound cuts off at higher volume on them pretty badly...

 

[cdhknives]

Youtube clip of the lathe running, note the high speeds exceed the ability of the phone mic to accurately depict:

 

[coolidge]

That doesn't sound healthy, like a bearing is going out, for a belt drive I thought it would be much quieter. I know nada about such lathes hopefully some of the forum members who do will chime in.

 

[pdentrem]

I wrote all this base upon your earlier post, but you got the video up before I got it done.
I hear a bad spindle bearing.



You can ignore the rest but it may be of use to someone else in the future

Motor has 2 bearings/bushings, countershaft has 2 roller bearings and the spindle has 2 bearings/bushings. The motor is easy to test. Remove the belt.

The countershaft bearings run directly on the shaft, would be well worth taking the time to dissemble the countershaft. Those small roller bearings are sensitive to grit. I had to strip and clean them, polish the shaft and remove the dried out grease in the shaft.

Spin the spindle by hand and use a stethoscope or a rod to your ear and listen for any noise. Do the same with the countershaft. Have to control the belts some how unless you have link belts installed.
Pierre

 

[Andre]

Looks like your lathe has taper roller bearings, I would assume those to be the culprit.