What Makes It Noisey

dusty · Post by **dusty** » Tue Apr 02, 2013 8:43 am

What makes a Mark V noisy?

I would not think that the quill assembly contributes much to the noise level.

Nor would suspect the idler shaft assembly or the sheaves.

I suspected the motor but when I isolate the motor from the rest of the drive train it is as quiet as can be.

Does all that noise get generated by the drive belt against the sheaves?

My second Mark V is much noisier than the other one and it has been rebuilt with all new bearings (except the motor) and new belts. It is an older model (different casting) but I would not think that would make the difference. I am stumped.

I would not (did not) think a thing about that when I rebuilt it but the other day my son-in-law was here and we were in the shop working when he asked why one was so much louder than the other. I obviously had no answer.

mrhart · Post by **mrhart** » Tue Apr 02, 2013 8:46 am

Is it a "female" Mark V ?

ss50th · Post by **ss50th** » Tue Apr 02, 2013 9:10 am

mrhart wrote:Is it a "female" Mark V ?

Probably not. Those don't have an "off" button.

nuhobby · Post by **nuhobby** » Tue Apr 02, 2013 10:59 am

The Mark V headstock has many possible modes of vibration. One "good doctor" wrote up some of them in his articles:
http://shopmachineadventures.com/

My own experience was opposite of dusty's. Usually my 'C casting' machine was louder than my 'B casting' machine. On a small group of samples, I believe it's easy to mis-assign the causes of noises. I suspect tiny things like sheave-to-shaft clearances are pretty significant at some resonance points.

Ultimately, my 'C casting' was converted to PowerPro, so it's way quieter now.

dusty · Post by **dusty** » Tue Apr 02, 2013 12:57 pm

nuhobby wrote:The Mark V headstock has many possible modes of vibration. One "good doctor" wrote up some of them in his articles:
http://shopmachineadventures.com/

My own experience was opposite of dusty's. Usually my 'C casting' machine was louder than my 'B casting' machine. On a small group of samples, I believe it's easy to mis-assign the causes of noises. I suspect tiny things like sheave-to-shaft clearances are pretty significant at some resonance points.

Ultimately, my 'C casting' was converted to PowerPro, so it's way quieter now.

Strangely enough, I have the reverse situation. The older machine, a "B" casting", is the loudest.

There are no strange noises. It is just louder and has a slightly different sound. I think my wife would can it "a different pitch".

I have those magazines and will begin rereading the four articles tonight. I have read them before but was not paying attention to anything he might have said about noise levels. I was most interested in his discussion about changing the legs. I would like my machine about 6" lower - I THINK.

I would like the table lower in the saw mode but I am uncertain about the other modes.

Back on the subject. Noise level is my current distraction so I shall go read. Thank you for reminding me of those articles.

algale · Post by **algale** » Tue Apr 02, 2013 2:55 pm

After performing a high speed alignment/setting, I heard a new buzzing in my headstock. Just this weekend I figured out what it was: the speed control knob is buzzing. Touch the knob, buzzing stops. It never used to buzz and I can only guess that resetting the high speed somehow caused some new frequency that corresponds to that little knob.

Al

WmZiggy · Post by **WmZiggy** » Tue Apr 02, 2013 6:56 pm

At the Lowe's demo in Fargo a month ago I was surprised how quiet the PP was. The SS demo-man said it was because the motor is better isolated from the frame, but I suspect its the lack of shieves and so many other parts.

dusty · Post by **dusty** » Tue Apr 02, 2013 7:12 pm

WmZiggy wrote:At the Lowe's demo in Fargo a month ago I was surprised how quiet the PP was. The SS demo-man said it was because the motor is better isolated from the frame, but I suspect its the lack of shieves and so many other parts.

It is something other than motor noise. To be convinced of that, all you have to do is pull the drive belt and turn on the motor is a noisy old Mark V like mine. The motor is very quiet. Probably not as quiet as a PowerPro but it is not a major contributor to the typical Mark V noise level.

You may be right on with regard to the sheaves. I am wondering if polishing the sheaves would make a difference.

I know that Bill resurfaces the sheaves on units that he reconditions and I am wondering if maybe that is why.

WmZiggy · Post by **WmZiggy** » Tue Apr 02, 2013 7:43 pm

Vibration is tricky business, but I would think that polishing the sheaves would be worth the time and effort. If it reduces friction should reduce vibration.

algale · Post by **algale** » Tue Apr 02, 2013 7:46 pm

Might reducing friction also increase slippage and reduce torque?