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Noise reduction efforts - 10EE

bll230

Hot Rolled
Joined
Jun 14, 2007
Location
Las Vegas
Since finishing my 10EE in between making stuff I have been working to reduce the noise. The first thing I did was replace the big bearings in the reduction gearbox. I detailed this work in a previous thread, and while there was a slight reduction in the gearbox noise, it was less than I had hoped for.

Next I replaced the 4 sliders in the gearbox. Mine were worn, I knew it and ignored it, but I had to quit ignoring it. $40 each from Monarch. Best purchase I have made from them. The new sliders made a huge difference. Less rattle while running, and even more noticeable, my Parker 514 can stop the spindle in about a second, but before there would be a claptrap of noise when stopping. Now it stops with essentially no noise.

IMG_0970.jpg

Noise that I thought was coming from from the tach turned out to be the phenolic gears in the headstock. Can't do anything about that.

Along the way I borrowed Everettengineer's pulleys and was able to true my two pulleys. My lathe had been run with one belt for obviously many years and I had uneven wear between the two grooves, as well as uneven wear from one side to the other in each groove, on both pulleys. After truing the pulleys I was able to use two belts instead of one, which reduced the noise further. My theory on this is that with one belt, there is a very slight torsional vibration. As the belt hops around the effective diameter of the pulleys change, which changes the RPM, which is the same as a rotational acceleration/deceleration, which causes vibrations. Vibrations are noise. With two belts the hopping around of one belt is cancelled by the hopping around of the other belt which reduces the vibration and noise.

Next I trued the zinc idler pulleys. The wear grooves were different on both pulleys, so now with two belts both belts were not running on the same diameter which meant one or both had to slip. Slipping is noise. With the pulleys trued the noise decreased further. Dealing with the pulleys brought to light the bolt issue I asked about in a previous thread, and as a result I loctited the bearings onto the bushings on both pulleys. Further reduction in noise as there is no possible movement of the bearings on the bushings.

With the drive pulleys and idlers true it became apparent how inconsistent "identical" belts are in length. Browning offers a machine matching service to get belts as close as possible to the same length. Expensive, but now obviously worth it. With the matched belts the tension is even between the two belts so I was able to adjust the tension properly. There is less noise as the hopping around of the two belts is much more even than with the previous "identical" length belts and I don't have to compromise tension, with one belt too loose or the other belt too tight.

https://www.regalbeloit.com/-/media...Commercial-HVAC/Belt-Drive-Monthly-Vol-23.pdf

So now with all this accomplished the predominant noise is the whirring of the phenolic gears in the headstock, even up to 4000 RPM, pretty impressive.

Off-topic now. Cal showed his zirc fitting caps for the leadscrew and feed shaft bearings. I made removeable plugs out of delrin and used an o-ring to seal the fit. The two upper plugs have an extension to grip with pliers to remove, the ELSR rod plug doesn't need to be pulled out since the rod can be used to knock it out.

IMG_0961.jpgIMG_0963.jpgIMG_0968.jpg
 
Were you aware the belts hysteresis issue could have been solved without need of a perfect match by fabbing independent idlers and then... positioning them at slightly different points in the free span?

Bill, great suggestion. 10EE’s have two idler mount locations, so easy to implement.

Re: Tacho gear noise, I haven’t noticed it before. Maybe the tacho gear mesh needs adjusting or some parts need replacing. I have lots of tacho drive parts, going for cheap, so contact me if you want to pursue that.
 
Mine has two noisy issues. One is the blower, new motor and it works real good, I would like to dial it down a bit. The other is in backgear. All new bearings, etc, just those big gears and dogs howling, oh well. I know they went to a spined shaft in the backgear box replacing those big lug dogs. Maybe noise was the issue?
 
RC, thanks for the offer. I think the noise is coming from the top phenolic gear. It wobbles slightly, I trued it a bit so it would not rub on the oil wiper on the oil reservoir. I may try making a delrin replacement gear for it at some point, but I have my top cover siliconed in place and so far no oil seepage, so I don't want to open it up.
 
Marvelous work, and inspirational. Good on yah!

Were you aware the belts hysteresis issue could have been solved without need of a perfect match by fabbing independent idlers and then... positioning them at slightly different points in the free span.

Nope, you didn't think it through. With one worn sheave, a smaller diameter, the spindle is trying to run at two different speeds so one belt must slip.

Bill
 
No.. YOU didn't think it though. The driving and driven sheaves have to match when ganged. Of course

The sheaves on one pulley have to match *each other* in diameter. Otherwise the speed of the belts would be different and one would slip. Independent idlers wont help in any way. They only help with length differences between the belts.
 
The operative word here is SHEAVE, not idler. He started by cleaning up the difference in the spindle pulley. BTW, the motor pulley would wear also, but not as much because of the greater contact surface.

Bill
 
Interesting reading thoughts about different idler locations to give the two belts different harmonics, may try that at some point.

To clarify about the pulleys since some of the debate has been misdirected, I wrote:

"Along the way I borrowed Everettengineer's pulleys and was able to true my two pulleys."

I was lucky Mark had his lathe down getting the same spindle regrind I got. Mark lent me both his pulleys so I was able to true both my pulleys. The gearbox pulley had noticeably more wear than the spindle pulley. There was a slight snag in that Mark's lathe is a 3000 RPM machine and mine is a 4000 RPM lathe, so with his bigger spindle pulley I had to get a longer belt than what I had. $8 to Amazon.
 








 
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