G0704 - Chasing a more quiet spindle still


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Thread: G0704 - Chasing a more quiet spindle still

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    Default G0704 - Chasing a more quiet spindle still

    I'm trying to do everything I can do get a reasonably quiet spindle with a belt drive and servo spindle motor. I understand it will never be silent at 5000 RPM but it shouldn't be screaming.

    So far the best I've been able to get it is ~95dB at 3500 RPM. My motor isn't setup for 5000 RPM yet but I imagine it would be well over 100dB. This "best so far" setup uses upgraded tapered roller bearings (I had AC bearings and they were worse) and using single V belts with (I think) 4L belt profile. I've also tried J6 poly v belt pulleys and timing pulleys. The poly v is similar to the single v belt but slightly louder I believe. The timing pulleys are the loudest. I'm also using Hoss' 3D printed spline bushing. I'm not sure if it would work better printed in something other than PLA or if I made a bushing out of a different material somehow.

    I do have the stock bearings in the quill so my best guess is that those are what's making the excess noise. My other guess is that the stock spindle bearing preload nut is just garbage and it's not holding preload well enough so there is somehow excess noise due to some kind of play?

    I found this video where he is using a servo spindle motor and pulleys that aren't properly aligned and it sounds like it's whisper quiet at 3000 RPM. If I had my spindle sounding anything close to this I'd actually want to use my mill!



    For comparison's sake, here is my mill at 3500 RPM -



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    Default Re: G0704 - Chasing a more quiet spindle still

    Is the spline shaft for quill movement greased properly?



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    Default Re: G0704 - Chasing a more quiet spindle still

    @he1957 I will feel VERY stupid if that is the problem! I had cleaned it off when I first put new bearings in so that could very well be the issue. What type of grease should I use? I'll head to the store to get that as soon as I can.



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    Default Re: G0704 - Chasing a more quiet spindle still

    I used high compression general purpose molly (NLGI 2).

    Nah, don't feel silly, the machine is too dumb to tell you it aches :-)



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    Default Re: G0704 - Chasing a more quiet spindle still

    My spindle at 6k makes around 75 decibels according the Decibel X app that can be found on the app store.

    I have a v-belt setup, all of the quill components are removed including the quill shell and bearings. I'm using $12 (for both) bearings I got on ebay. They are ready to be changed as they get noisy when drilling.

    Suffice it to say, the real noise starts when the end mill hits the material.



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    Default Re: G0704 - Chasing a more quiet spindle still

    @CL_MotoTech 75dB is very reasonable for that. I also used a phone app to check mine. If greasing up the splines doesn't help my next step is to take out quill components and look further into the quill housing itself. Are you currently using AC bearings or tapered roller? I thought I read somewhere about AC wearing over time due to not being able to take an axial load as well, that's one reason I tried just upgrading the tapered roller bearings instead of continuing to use AC. All I want is real noise when chips start to fly! I have yet to do any extra machine strengthening/seeing how hard I can run it because I've been stuck on this noise issue for some time. Once that's sorted I have all sorts of half baked ideas. I've seen your name all around so I'm sure yours is pretty badass by now.

    @he1957 Gonna try some grease right now, wish me luck!



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    Default Re: G0704 - Chasing a more quiet spindle still

    I went from tapers to AC's back to tapers and I just bought a new set of AC's to replace my current tapers... haha. I still haven't figured out what I like best. The tapers seems to require less adjustment and seem to be less sensitive to adjustment, but the AC's tend to sap less horsepower. I think the tapers do a better job of transferring heat to the head which means they actually are more stable than the AC's, I think this contributes to the fickle nature of the AC's. Overall, I'd say I prefer tapers right now, but we will see how it goes with this new set of AC's (when I finally get around to installing them).

    I experimented with various methods to quiet the quill. Everything from peening the faces of the splines to o-ring dampers, Delrin dampers, new bearings, turning the quill shell, at the end of the day the biggest improvement came from getting rid of it and all it's components. With the v belt I don't run a lot of tension so I doubt I'm loading the spindle bearings too hard so I've never felt the need to run a support bearing at the top. I did machine a bearing cover for inside the head to seal off the top spindle bearing. It's just a delrin sheet that sits over the pocket, I added a fitting for an oil cup. I oil my spindle, I prefer that over grease as it helps purge the spindle of (the likely minimal) flood coolant, though a positive pressure system would be preferred. I lubricate using Marvel Mystery oil and have had great luck with this method.

    The spindle aven at 8k (it;s max) is pretty quiet. I probably wouldn't want to sleep in a room with it, but it certainly isn't an annoying level of noise either.



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    Default Re: G0704 - Chasing a more quiet spindle still

    @CL_MotoTech Ok so let me be sure I understand what you're saying. The whole quill assembly with the two bearings, spline shaped slot, and the gear (mine has a pulley built on because the machine I actually have is a Weiss VM25L and the #1 difference between a G0704 and it are that the G0704 is gear driven and the Weiss is HTD belt driven via a pulley on the quill) is completely removed and you fit a pulley onto the top of the splines, correct? If you haven't had any issues I'm more than willing to try this (especially since I have that piece taken out right now lol). I suppose if I ever felt it needed top support I could machine (or maybe even 3D print in nylon) a piece to fit inside the top bearing with the spline slot in it.

    Honestly my air compressor is probably more quiet than the spindle right now. I did add grease to the splines and it cut down on the "knocking" sound a bit but it was still in the 90dB range. I think I had to lower it to like 500 RPM to get it into the 70's like yours.

    Edit/Update: Ok so I tried running it without that quill component. It made it only about 5dB quieter. So what that tells me is that it should be a bearing preload issue, right? Or maybe these bearings need to be run in for a real long time before their sound starts to dissipate? I ran them yesterday when I installed them for 10min at 250, 500, 1000, 2000, and 3500 RPM but maybe it should go longer. Greased them with the high roller kluber grease.

    Last edited by steelcogs; 02-09-2019 at 07:24 PM.


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    Default Re: G0704 - Chasing a more quiet spindle still

    What I found on mine is that most of the noise comes from the poor fit of the quill spline. The concentricity between the quill and the drive shaft is not great, and it only gets worse when you tighten the quill stop on the left side. Do a test while the mill is running. Just loosen the quill stop screw and see if the noise is reduced. Also the thickest grease you can find on the spline should help.

    I also found that a smaller belt made a difference. I tried a 2L180 belt and a O-450E. I can't remember which I settled on, but both worked. The smaller size let the belt fit better in the pulley and required less tension.

    Last edited by maxspongebob; 02-09-2019 at 08:34 PM.


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    Default Re: G0704 - Chasing a more quiet spindle still

    @maxspongebob I tried loosening the screw and it didn't change anything. I will say that is very dumb that it makes a difference for you.

    I just did a couple different things. What material are the V belt pulleys everybody is using? I can only find cast iron or nylon (and occasionally zinc) ones, and cast iron are typically the only ones with a set screw. I noticed the cast iron V belt pulley alone on the motor (so not connected to the spindle) makes a good amount of noise vs. the aluminum timing pulley I have. Of course the timing pulleys are loud themselves when actually using them. I'm wondering how an aluminum 3L or 4L V belt pulley would sound but I don't have any means to make one. I'm half tempted to 3D print two 4L pulleys just to hear how they sound running the spindle since they'd be so lightweight.



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    Default Re: G0704 - Chasing a more quiet spindle still

    I am a bit confused. You said "the cast iron V belt pulley alone on the motor (so not connected to the spindle) makes a good amount of noise" Just the pulley on the motor with no belt makes noise?

    Also I have aluminum pulleys.



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    Default Re: G0704 - Chasing a more quiet spindle still

    Something to try:
    Drop the whole spindle out the bottom and then see how much noise it makes. If the spline shaft is not engaged, you should only hear the noise of the belt, pulley and pulley shaft bearings.

    Oops just read that you tried that.



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G0704 - Chasing a more quiet spindle still

G0704 - Chasing a more quiet spindle still