[steelcogs]

Let me think out loud for a second.

If the motor with a heavy pulley installed makes more noise than the motor with a light pulley, what is the difference?
What could cause this? Pulley out of balance causing a vibration in the motor internals?

If both pulleys are tight to the shaft, then a noise difference must be generated internal to the motor.
Out of balance could cause the motor bearings to chatter. Out of balance at high RPM could cause excessive motor bearing loads. Adding more load with belt tension may make situation worse.

Does the motor without a pulley make any noise? It shouldn't.
Does a radial load applied to the motor shaft make a noise? (how to test?)
Is there run out on the motor bearings?

The motor without a pulley sounds as you'd expect it to. I don't know how/why the cast iron pulley would be out of balance since it's brand new and made for the shaft, it's not custom like the one I have to open the bore for the spline shaft. It's possible that it's only rated for a certain RPM which is well below 3500.

[steelcogs]

Actually that's not a bad idea granted I can find a good way to mount the motor.

[maxspongebob]

I was just looking on McMaster Carr for a pulley. What is the shaft size and the outer diameter? You said it is a 3L profile correct?

[steelcogs]

My motor shaft size is 1/2" and it can be 3L or 4L as long as both the spindle and motor pulleys are the same pitch and diameter (I use 1:1 ratio). The second pulley I bore to .853 ish to fit on the splines. But McMaster, Grainger, etc. I can't find anywhere that doesn't use either plastic or cast iron/zinc pulleys.

[maxspongebob]

What was the outside diameter?

[steelcogs]

OD can be anything from 2.5"-3" as long as both pulleys have the same OD.

I also just test the direct connect method and dB reading just the motor shaft. Unmounted (so it could be causing vibrations) it goes from an ambient 60dB to 77ish. So the motor itself creates 17dB. Direct connecting it was much quieter at ~80dB ish. The bearings do definitely make some noise though. I'm not sure if they just need time to be run in or if the preload is incorrect. I'm banking on that because I just noticed a very slight bit of both axial and radial play. That shoots red flags to me that there isn't enough preload because I don't see how else a brand new bearing set that has press fit fitment would allow movement. But I also don't have a tool or know what tools to get to really crank down the preload nut. My makeshift one must not be cutting it. Or the preload nut is just garbage and doesn't work well for whatever reason. It's cranked as well as I can get it with my tool.

[maxspongebob]

You need a spanner wrench. Here is what it would look like. This one was made by a G0704 owner who also needed to set the preload. https://grabcad.com/library/g0704-spindle-pin-spanner-1

Yep, definitely need to adjust the bearings. I also used the tapered bearings. They work well and mine are quiet.

The nut is absolutely a crap design. Here is a guy that made his own. https://www.youtube.com/watch?v=f6sFsGC0-fM

[maxspongebob]

I have one of these that I used on mine.
https://www.amazon.com/Universal-Fin...-4-spons&psc=1

[steelcogs]

I have a makeshift one, his is a lot nicer though lol. I may be able to weld some scrap together to make one more like his out of steel. I also saw that preload nut video a long time ago (and just watched it again like an hour ago) and that one is so much nicer. I just don't have a lathe to make it on lol.

[maxspongebob]

I was just looking at the VM25 users manual and on page 26 is the head diagram. Do you still have part # 206 installed? If you are no longer using the quill can you remove this and eliminate it's noise as well?

http://wdl5.streamhoster.com/hvp/DROPROS/VM25L.pdf

EDIT: I just looked at your video again. Yes, I see the gaping hole in the top. Those parts are not there. OK. Time for me to get some shuteye.

[steelcogs]

I ordered a couple different spanners so hopefully that helps me out. I swear I looked on Amazon for some adjustable ones before but didn't find anything. Apparently I didn't...

[CL_MotoTech]

Make a spanner out of a crescent wrench, it works fantastic. An 8" or 10" crescent wrench from HF is just a few dollars.

[Fastest1]

Make a spanner out of a crescent wrench, it works fantastic. An 8" or 10" crescent wrench from HF is just a few dollars.

This is exactly what I built years ago. Still have it and it works great.


Sent from my iPhone using Tapatalk Pro

[maxspongebob]

I love that crescent spanner. Great idea.

If you think it is really an aluminum pulley that you need to solve the problem, send me a drawing of what you want it to look like. I won't be at my shop until Thursday, but I may be able to turn one for you.

[steelcogs]

@CL_MotorTech That's a great idea, it would likely have a lot more leverage than an actual spanner too. Have you every had any issues with the screws bending? My makeshift one I used some scrap aluminum that I bent two sides out like a fork, drilled and tapped two holes and put SST socket head screws through. It seems like the screws bend more easily than the aluminum though in my experience.

@maxspongebob Let me see how it goes getting me preload correct first. I'm sure the final solution will end up involving pulleys that are aluminum but I'll just have to see first. That's a very generous offer and if I need a set I'm willing to pay.

[109jb]

It just goes onto the shaft, it's not counterbored to rest on that protruding part.

If that is the case then I would say that is a likely culprit. Attaching only to the spline shaft means that as the spindle rotates, belt tension is pulling on that shaft. There will be flex on the shaft and it will move in the internal spline and make a bunch of racket.

[CL_MotoTech]

I use m4 bolts in mine. I actually use it all the time, like almost daily, for a specific part I maintenance. Yes, I have broken the bolts off many times. Luckily the M4's just break off at the thread, you toss the broken bit out, then move the bolt down.

I've noticed that having the thread adds a significant amount of holding power as it tends to hold the pin in the pocket. I made a set of pins with smooth shafts and instantly realized they were inferior so I went back to just using plain bolts. The smooth pins want to slip.

[steelcogs]

Ok so quick update:

Bearing preload had a lot to do with the noise and 100% of the axial and radial play I had, just as I'd thought. There was a tough spot in the preload nut's threads (or on the spline's threads) that I wasn't able to crack with my homemade spanner wrench. Once I got a real one and something to hold the bottom of the spindle better I was able to tighten it up. I'll have to make sure that the bearings don't get too hot but IIRC I tightened it just enough to remove any play. It's not as smooth as before but that might come as I actually use the bearings.

At 3500RPM with timing pulleys I'm at ~83-84dB. Better than the 90 something I was originally at but a lot of that noise is still coming just from the pulleys. @maxspongebob I'm going to model up some pulleys then message you to see about turning them for me. My hope is that once the servo motor is working at 5000 RPM (as it should be, apparently I need to exchange my driver for one with a newer firmware) I can get the spindle to be in the ?80dB.

[ninefinger]

Your bearings maybe be bad if you have noise and lack of smoothness. A good bearing should be nearly silent. Got a photo of what setup is making what level of noise?

Mike

[steelcogs]

A good portion of the noise at this point comes solely from the motor itself. Running the motor dry with no pulleys it was something like 75dB which is pretty reasonable. I don't know exactly what to expect noise wise from a servo motor other than the DMM servo's website says they are less than 60dB. I assume that means they make less than 60dB as I was measuring an ambient 60ish dB in my garage. Running timing pulleys, which create some noise themselves, I was measuring ~85dB at 3500 RPM. With a good pulley set I think that will be down to 80dB but I won't know until I have them. I'm pretty sure this is the largest source of noise at this point but it seems like even two people with the same setup on different machines can even have a large difference in noise.

The bearings are new taper roller bearings (that can handle the RPM unlike the stock ones) so they shouldn't be bad. My guess for any lack of smoothness is just the preload nut not being very good. Once I actually had decent preload on them the quieted down a good bit and it pulled out and axial/radial play I could feel in the shaft.