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Lathe vibration detector ideas please!

odie

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I am looking for ideas for devices, or inventions for detecting minor vibrations on the lathe.

The purpose is to adjust the rpm to where the least possible vibrations are present.

Right now, I use my fingertips on the lathe bed, plus there is one long neck spot lamp that consistently gives me some good indications. Other lamps and fixtures on the headstock also help.

Assuming the best location would be connected to the headstock, but entertaining input, if any.

I have tried an antennae like affair that was not very successful.

I also have experimented with a jar of water, that was also not very successful. It was a good idea, but not any more useful than the long neck spot lamp. (Possibly if the surface area of the water was enlarged.....something like a frying pan.....maybe it would be more applicable.....?)

OK, guys and gals.......turn some mental gears!

Let's build this thing! :D

-----odie-----
 
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I don't think you can do better than the long arm lamps. The flex elbow ones especially. It would be interesting to have them mounted in 3 axis orientation, vertical, horizontal, and lateral to see what kind of oscillations you get....

robo hippy
 
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In the industrial world they still use a limit switch arraignment that utilize a ball bearing sitting on a cup that would fall off the cup when a specified level of vibration was detected on the surface that the enclosed vibration switch is mounted. The ball bearing would fall onto the limit switch closing the electrical circuit which would activate an alarm or safety interlock circuit shutting the system down.

The ancient Chinese also used a similar design whereas a ball would drop off of its support indicating the direction a seismic event had taken place in the country, this was a large round vessel that would amplify the vibrations and displace a number of balls that surrounded the vessel each one having its own support arranged in a 360 degree pattern surrounding the vessel.

Modern technology utilize solid state piezo technology sensors that produce an output usually 4-20ma to indicate a specific level of vibration, a digital display that operates from the 4-20ma output can provide a numerical value of the vibration as it is incurred on the equipment.
 
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Odie - Just a thought, but could it be that the problem lies not in your method of measuring but in the magnitude of the effect you’re trying to measure? If you’re having trouble measuring it, it may not be a problem...
My lathe is pretty well setup, but is on a wooden floor structure. I’ve been able to eliminate nearly all vibration, but still chase some at certain frequencies. I doubt that they will ever be eliminated completely, and I’ve made peace with that and decided to live in harmony and just avoid it whenever possible.
You mention that you tried a jar of water - I found, purely by accident, that if you put a large diameter magnet (like the cheap ones they sell at HF in the bottom of a sturdy plastic measuring beaker (like they sell in the paint dept at HD) put a small amount of DNA in it and move it to various spots on your lathe, its pretty amazing what small vibrations show up. The magnet holds it in close contact, also allows you to dip a rag to clean up as you measure...just a thought.
 

odie

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Thank you for your replies, gentlemen........I've been in the shop experimenting with the antennae idea. So far, I've not found a solution that outperforms the spot lamp. I've used .032 stainless wire, .050 bailing wire, a plastic rod.....long pieces and shorter pieces, straight and bent. (The spot lamp has a bend, not straight.)

I will take a photo of what I've come up with today......so far, the bailing wire seems to work the best.....bent.

I will try the phone app, just to see if it detects what I don't already detect.....later....and thank you for this suggestion.

It's true that some inherent vibrations will be the lathe itself.....that will not be eliminated completely, but they can be reduced with the best rpm.....trying to find the best rpm, not to eliminate what can't be eliminated. I suppose it is possible that I won't get any improvement in my finest cuts, even if I can reduce the vibrations further than I already do......the lamp, and my fingers do a decent job of this.

I'm out in the shop right now.....have a laptop out here......still contemplating the issue...... :confused: :D

-----odie-----
 

odie

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OK, I've attached a magnet to the bottom of a glass jar, and filled with rubbing alcohol. I added a little dye to the alcohol so that it is better for observation. From first indication, it appears to be a little more sensitive than the spot lamp. I've got the spot lamp, the .050" bailing wire jig, and the glass container with the alcohol. All these things are attached to the headstock. I think this is a better combination of vibration detectors than using the spot lamp + fingers only.....time will tell! :rolleyes:

Still, even if I can fine tune the rpm for a lesser vibration, I'm unsure if it will mean I can improve my finest of cuts.....that, I'm happy with as is......but, if it can be improved, I'm all for it! ;)

I'll take a photo and show you what I've come up with later today.

Still want to download the vibration app.......later on that.

I'm still open to suggestions, friends! :D

-----odie-----
 
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First thought was a variation on the antenna or baling wire. I'd try a stiff piece of wire and hang a Styrofoam or other very light weight ball from a thread on the end of the wire. I suggest a stiff piece of wire as the thin baling wire may flex enough to dampen vibrations.

If it doesn't work, you at least have a toy for the cats.;)
 

odie

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All you need is a glass of water.

Hi John.....:D

Still out in the shop....and responding on the laptop,

Actually, I did use water the first time I tried this, and it's my opinion that the thinner alcohol is a little more responsive to the vibrations than water. Not by much, I think, but detectable. Admittedly so, I'm currently working on a nice piece of madrone burl that is inherently very balanced to begin with. There is a detectable vibration around 7-800 rpm, and best rpm is around 1000 rpm. This is why I'm reserving final judgement on any of these methods of determining where the vibrations exist, until I have turned several bowls using them.

-----odie-----
 
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Richard, seems like there is an app for everything. I liked the comment from the guy who mentioned the earth quake "rectal scale"...
odie, years ago I posted my lamp with laser in the tips and tricks section, used to "point" out a ridge or some area on the turning that needed some work without having to mark the piece. I also use it to dial through lathe vibration. I point it at the wall and can increase lathe speed through a vibration point and the vibrations settle out, increasing the speed will approach another vibration point. The pointer is more sensitive as shown as opposed to straight up. I still like to feel the lathe, this just gives a visual input...
Laser light.jpg OOB vibration.jpg Dialed in.jpeg
Laser light.............................Vibration.....................Dialed in
 
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Clifton's idea using a laser should work for this purpose and you can purchase one for a $1.00 at the Dollar store if you don't already have one. You could easily mark a graph line on the wall to measure the level of vibration.
 

odie

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Richard, seems like there is an app for everything. I liked the comment from the guy who mentioned the earth quake "rectal scale"...
odie, years ago I posted my lamp with laser in the tips and tricks section, used to "point" out a ridge or some area on the turning that needed some work without having to mark the piece. I also use it to dial through lathe vibration. I point it at the wall and can increase lathe speed through a vibration point and the vibrations settle out, increasing the speed will approach another vibration point. The pointer is more sensitive as shown as opposed to straight up. I still like to feel the lathe, this just gives a visual input...
View attachment 28932 View attachment 28933 View attachment 28934
Laser light.............................Vibration.....................Dialed in

Great idea! I'm going to do some experimenting with this for sure! :D

-----odie-----
 

odie

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How about a thin wire with laser (cat toy) mounted to it and point that at the wall. The wire could actually be taped to the headstock.

Thanks Gerald, this is an idea I think will work well.....

-----odie-----
 

odie

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This is what I'm going to be testing for the next few bowls. The bailing wire is attached to a wood block that has magnets taped to it.....and, the dye colored alcohol in the glass container. Both attached to the headstock.
IMG_4782.JPG IMG_4783.JPG
-----odie-----
 
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Bill Boehme

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When I first started turning I strongly considered buying the old Woodfast that belonged to my club ... the club upgraded to a PM3520. The Woodfast had the Craft Supplies variable speed kit which used a DC motor with a Minarik controller. However, it was terribly rusty and noisy.
 

odie

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When I first started turning I strongly considered buying the old Woodfast that belonged to my club ... the club upgraded to a PM3520. The Woodfast had the Craft Supplies variable speed kit which used a DC motor with a Minarik controller. However, it was terribly rusty and noisy.


......and, your point is, Bill? :confused:

-----odie-----
 

Bill Boehme

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Senility. :D That's my point. I started the post about eight hours ago and then saw that I didn't hit the post button. I didn't notice that I didn't finish it and now I don't remember exactly what I was going to say. Duh!

I forgot to add that it also vibrated even with nothing mounted. I already had a vibrating lathe and didn't need another one. :eek:
 

odie

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Senility. :D That's my point. I started the post about eight hours ago and then saw that I didn't hit the post button. I didn't notice that I didn't finish it and now I don't remember exactly what I was going to say. Duh!

I forgot to add that it also vibrated even with nothing mounted. I already had a vibrating lathe and didn't need another one. :eek:

I think this senility thing gets worse, and compounds with age! :eek:

If your intent is to draw a relationship between the rusted lathe you didn't buy, and my Woodfast lathe, I don't think that is a fair comparison. Because I'm chasing vibrations is nothing more than splitting hairs on my part, trying to find solutions for out of balance wood that can be dealt with. My lathe has been well maintained, rust free, and very smooth running. There is no detectable vibration with nothing mounted to the spindle. The kind of refined results I'm getting is a testament to that very thing. I could never get this kind of results if there were an inherent vibration problem with the lathe itself. It's the reason I have decided to keep it, instead of purchasing a new lathe. The only real problem I've had in recent times, is a banjo that has warped a few thousandths over the past 27 years of continual use.....and, as you know, I purchased a Robust banjo that has been a tremendous improvement.

It bothers me some to think that some turners value their worth on the money they have invested, rather than understand the equipment is a vehicle driven by the level of skill that can be transferred through their hands to the equipment.

-----odie-----
 

john lucas

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You haven't had fun until you turn on an old Delta 46-700 table top lathe with reeves drive. I used to chase that thing across the shop and even sitting still with nothing on the spindle it would vibrate. They pulleys broke often and one time when they were back ordered I decided to buy a Nova Comet. This was the first model and probably one of the first cast iron mini lathes. I ran so smooth my turning improved overnight. I sold the Delta as soon as I got it repaired.
 
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27 years is a good run! I think think that you can get another 27!
Could the bearings have worn down a tad? When was the last time you checked for runout? My oneway live center’s bearings developed some slop after 18 years of use and I replace them. Recently I checked and releveled all the legs. One of my leg adjustments didn’t sit firmly on the floor as originally setup. Conditions do change. “Tuneups” are necessary every now and then. I am Not saying you have any of these issues but it’s alot easier perhaps cheaper to eliminate problems than to build systems to track them.
 

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While minimizing the lathe vibration is a good thing.
A leveled lathe with a solid base and good bearings contributes almost no vibration compared to:
The mounting method
Weight balance and distribution of the Wood’s mass
The wood’s mass or lack of mass toward the drive side
The tool, the cut, feed rate, bevel pressure, position on the tool rest, distance over the tool rest

My Woodfast rattles a whole lot more than my General which rattles a whole lot more than my ONEWAY
However I can turn a finial, 1/16” walled hollow ball, or thin walled NE bowl that is just as nice on the Woodfast as one done on the ONEWAY.
Just have to pay attention to the wood and tool use not the machine

The bottom line- Good technique will produce good results on a crappy lathe
Crappy techniques will produce crappy results on a good lathe.

Getting a nice surface on asymmetrical out of balance work has a lot more to do with fine tuning technique than fine tuning the lathe.
 

odie

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27 years is a good run! I think think that you can get another 27!
Could the bearings have worn down a tad? When was the last time you checked for runout? My oneway live center’s bearings developed some slop after 18 years of use and I replace them. Recently I checked and releveled all the legs. One of my leg adjustments didn’t sit firmly on the floor as originally setup. Conditions do change. “Tuneups” are necessary every now and then. I am Not saying you have any of these issues but it’s alot easier perhaps cheaper to eliminate problems than to build systems to track them.

Hello Dennis......the bearings were replaced about 2 years ago, and the lathe is bolted to the cement floor. Been awhile since I checked the runout. Besides bad bearings, is there anything that would change the runout.....with the exception of a bent spindle? I suppose I should check, just out of curiosity, but I've had no events that would make me suspect there is any problems. My Woodfast has no detectable vibrations with nothing mounted, at any rpm. Hopefully I can live long enough to get another 27......the lathe will be here long after I'm gone! :D

-----odie-----
 
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I think that as our skills get better we can concentrate on other parts of the equation. Twenty some years ago I worked with some racing fans, so, I watched a few races, and learned there is audio from the drivers. It amazed me when I heard one driver say as he was coming in for a pitstop that he needed a 1/4 pound of air in his right front tire. I can't feel when I'm six pounds low let alone 1/4 psi. I think it was The Splintered History of Wood where I read of a baseball player who sent his bats back because they didn't feel right. When measured, the handles were a few thousandths too large. These guys know their stuff, and know their equipment. I think we are the same in a sense. I have some duplicate tools, they look the same, they are sharpened the same, but they cut different, I don't know why, but I can feel it, I can tell. I grab one instead of the other because I feel, or think it does what I want. True? I don't know, but true to me.
I level my lathe, front back, side to side. Then, with clean M/T sockets and good points bring the tailstock up to the headstock to check the alignment. And guess what, off by half a skosh. Which leg do I adjust? At this point, any leg would do, but no, out with the level. A few rounds, some internal rationalization and it's this leg. It's only a 1/4 turn of the leveling bolt, any leg would do, but it's this leg.
Vibrations, harmonic imbalance, I don't want to turn in that range, so I dial out of it. How? As odie says, fingers work, but what's the next level? There are vibration meters that cost thousands of dollars, I'm a kook, but not that much of a kook...
Saying "it's wood. It moves. Get over it" misses the point. There is a point of diminishing returns. I'm not measuring with NASA precision, just tweaking the equation. I'm glad I'm not the only one...
 
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Any wire , rod or fluid filled container will have a natural frequency of its own and show a magnified response at or near its natural frequency. This will distort any result.
What you need is a measure of the vibration where the tool meets the wood. This is a combination of the lathe rotation vibration measured at the head stock, the vibration of the tool post and the variation of the wood grain hardness.
No I don't have a solution except your skill and experience.
Stu
 
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odie

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I think that as our skills get better we can concentrate on other parts of the equation. Twenty some years ago I worked with some racing fans, so, I watched a few races, and learned there is audio from the drivers. It amazed me when I heard one driver say as he was coming in for a pitstop that he needed a 1/4 pound of air in his right front tire. I can't feel when I'm six pounds low let alone 1/4 psi. I think it was The Splintered History of Wood where I read of a baseball player who sent his bats back because they didn't feel right. When measured, the handles were a few thousandths too large. These guys know their stuff, and know their equipment. I think we are the same in a sense. I have some duplicate tools, they look the same, they are sharpened the same, but they cut different, I don't know why, but I can feel it, I can tell. I grab one instead of the other because I feel, or think it does what I want. True? I don't know, but true to me.
I level my lathe, front back, side to side. Then, with clean M/T sockets and good points bring the tailstock up to the headstock to check the alignment. And guess what, off by half a skosh. Which leg do I adjust? At this point, any leg would do, but no, out with the level. A few rounds, some internal rationalization and it's this leg. It's only a 1/4 turn of the leveling bolt, any leg would do, but it's this leg.
Vibrations, harmonic imbalance, I don't want to turn in that range, so I dial out of it. How? As odie says, fingers work, but what's the next level? There are vibration meters that cost thousands of dollars, I'm a kook, but not that much of a kook...
Saying "it's wood. It moves. Get over it" misses the point. There is a point of diminishing returns. I'm not measuring with NASA precision, just tweaking the equation. I'm glad I'm not the only one...

Very excellent post, Clifton. :D

I went out to the shop and rebuffed a couple sold bowls (Amazing that I sold two bowls on an Easter Sunday! o_O).....while doing that, my curiosity made me drag out the dial indicator and magnetic base. My dial indicator isn't made to measure this fine of a readout, but my spindle runout is close to a quarter of a thousandth, or .00025". I also checked once again for any inherent lathe vibration with nothing mounted at all.......As before there was no detectable vibration throughout the range of rpm. I'm sure my Woodfast lathe may have some vibration, because it isn't a theoretically perfect piece of machinery......just that I can't detect any vibration at all. Any vibration I'm attempting to eliminate with an adjustment of the rpm is strictly with the current piece of wood, and not the lathe.

Clifton is right, and I may be chasing ghosts with my attempts to fine tune for vibration with any more indication than the spot lamp and fingers have given me. This doesn't mean that I won't keep trying to improve my turning any way possible......but, I may find this particular endeavor an effort in futility. :eek:

-----odie-----
 
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Very excellent post, Clifton. :D

my Woodfast lathe may have some vibration, because it isn't a theoretically perfect piece of machinery......just that I can't detect any vibration at all. Any vibration I'm attempting to eliminate with an adjustment of the rpm is strictly with the current piece of wood, and not the lathe.

Clifton is right, and I may be chasing ghosts with my attempts to fine tune for vibration with any more indication than the spot lamp and fingers have given me. This doesn't mean that I won't keep trying to improve my turning any way possible......but, I may find this particular endeavor an effort in futility. :eek:

-----odie-----


Odie I agree with your summation of chasing vibration when none is detectable in the machine then the blank is the culprit. But wait what about something else like the stress induced by the spinning blank on the spindle and bearings?

Also look at the vibration after the blank is balanced or rounded out which is the point at which vibration influences the final product. Is it there?
 

odie

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Odie I agree with your summation of chasing vibration when none is detectable in the machine then the blank is the culprit. But wait what about something else like the stress induced by the spinning blank on the spindle and bearings?

Also look at the vibration after the blank is balanced or rounded out which is the point at which vibration influences the final product. Is it there?

Could be, Gerald.......How could that be determined? I suppose if the bearings were worn, that would influence the kind of stresses you mention here.....?

I have found that significant changes in vibration are usually found while eliminating a volume of wood, as in the roughing stage. There, while hogging wood, the vibration isn't as meaningful to an extra clean cut as it is in the later stages of the turning.....not nearly as critical as when taking those last few final finish cuts prior to sanding......agreed?

The vibration normally doesn't change the best rpm very much when the seasoning is done, and the bowl is on the 2nd turning. It does sometimes, but usually not a significant amount. These are the most critical cuts you can make, and with hard/dense woods, will make the difference between starting your sanding at 180 or 320! If the latter, then the quality of the details will be crisp, and appear very cleanly done to the eye.

-----odie-----
 

Bill Boehme

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If your intent is to draw a relationship between the rusted lathe you didn't buy, and my Woodfast lathe, I don't think that is a fair comparison.

No, I was just thinking about the condition of the lathe. Lathes that belong to clubs seem to get a lot of abuse and neglect. We get some demonstrators that are pretty rough on lathes. And, in classes a lot of students don't treat lathes very nicely. Before that my first lathe, a Delta 46-715, was horrible about vibrating. It was very similar to the one that John Lucas had. But, I get your point that you are talking about minute levels of vibration and not my personal horror stories.

You haven't had fun until you turn on an old Delta 46-700 table top lathe with reeves drive. I used to chase that thing across the shop and even sitting still with nothing on the spindle it would vibrate ......

After my first two exposures to vibrating lathes I was thinking that maybe all lathes were like that.
 
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It’s new……It’s amazing…..It’s amazing and new…
.
It’s the new, MK1 mod2
.
odie inspired……… “LATHE VIBROMETER”.
.
After countless hours of research, it is finally available in a scrap pile near you.
.
Using advanced digital technology, combined with elasto polymer banding, stabilized using an ancient three point system by combining modern rare earth neodymium magnets, this never before seen device will amaze your friends and astound your neighbors.
.
Obviously I’m playing today… For some reason, I feel I should be painting a fence. And no, it does not come with a pair of Ginsue knives.
.
The funny thing is, it works. Just like the lamp mounted pointer, as the speed changes, the size of the laser circle changes, giving you a visual of lathe vibrations…

Front OLVM.jpeg Back OLVM.jpeg Bottom OLVM.jpeg
 

odie

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It’s new……It’s amazing…..It’s amazing and new…
.
It’s the new, MK1 mod2
.
odie inspired……… “LATHE VIBROMETER”.
.
After countless hours of research, it is finally available in a scrap pile near you.
.
Using advanced digital technology, combined with elasto polymer banding, stabilized using an ancient three point system by combining modern rare earth neodymium magnets, this never before seen device will amaze your friends and astound your neighbors.
.
Obviously I’m playing today… For some reason, I feel I should be painting a fence. And no, it does not come with a pair of Ginsue knives.
.
The funny thing is, it works. Just like the lamp mounted pointer, as the speed changes, the size of the laser circle changes, giving you a visual of lathe vibrations…

View attachment 28954 View attachment 28955 View attachment 28956

Excellent!.......I'll have to make one of those! Thank you, Clifton :D

-----odie-----
 

odie

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The funny thing is, it works.

Yes, it does work! Success.....I am detecting vibrations that I was unable to detect before.....this "Lathe Vibrometer" is a keeper......thank you very much for contributing, Clifton. I have to ask, though......is this your own idea, or did you see this somewhere? Whoever originally thought of this, is a genius! :D

At first, I was pointing the laser at the wall next to the lathe, and that didn't work very well. I then pointed the laser clear across to the other end of the shop. (about 20', or so) From that distance, I began detecting vibrations I was unable to in the past......just great! :D

-----odie-----

IMG_4784.JPG
IMG_4785_LI.jpg
 
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odie, I was mulling over your statements about "chasing ghosts" and, "an effort in futility" and thought, I don't think either one is true.
Then I thought about a guy who came up with a thousand ways to not make a light bulb, then of the slinky and silly putty. Both sort of accidental discoveries. Even if it (chasing vibrations) doesn't pan out, other discoveries are usually made along the way, making the journey relevant.

Just read your last post, yes, this was a 2 AM flash of inspiration. I almost got up but cooler heads prevailed. Mod 1 (at 6 AM) was this, using a holding device from another project for proof of concept. The pen laser was too light, the bore site laser being heavier worked much better. I like your construction...
A fun project...
Mod1.jpeg
 

odie

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Ps Using lighter "elasto polymer bands" will increase sensitivity...

Roger that.......At the moment, I don't have any lighter rubber bands, but it will be easy to change these out to something else later. :D

You're right about the "scrap pile" thing.......I just read your original post a couple hours ago, and made my version from parts and pieces I had on hand! ;)

-----odie-----
 

Emiliano Achaval

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I have been following this, entirely for entertainment purposes. Luckily I have a lathe that I don't have to worry about vibration. With all the steel plates I added below, plus the welded heavy steel beams to them, and almost 300 lbs of sand, if I do have any vibration I turn the speed down, LOL I would go with the laser mounted on some sort of wire to see vibration, if I had to...
 
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Vibration monitoring is an industry practice, it protects machines and components, and probably people. Turners, do it by eye, ear, feel and experience. The OLVM (odies lathe vibrometer) gives a visual representation. Interestingly, you can increase the speed thru a vibration point and see it settle out on the other side. Always necessary? No. Still, it was a fun project...
 

odie

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Clifton is correct.....sometimes the best rpm is a faster rpm than where any vibration is.....and, sometimes it's slower. Sometimes there is more than one rpm where vibration can occur......and, sometimes there is none at all. Finding a best rpm isn't always necessary, but under some circumstances, it most definitely is. Some hard and dense woods......like dry desert ironwood, or marblewood, among many others, are much more difficult to get a fine clean cut than other more commonly used woods. However, even the easiest to turn woods can be difficult to cut cleanly if trying to do it at a specific rpm where harmonic vibrations do occur. The importance of all this mainly depends on what kind of turning you do. If a turner desires to produce fine details, then it's much more critical than someone who relies on power sanding to finish off less than perfect cuts. Power sanding, or any unnecessary excessive sanding is what destroys geometric integrity, and the possibility of producing those very desirable fine details. If the fine details are the objective, then it's very critical to start the sanding on as fine a grit as possible.

Emiliano......You should re-think your philosophy on this......because the lathe isn't the source of the vibration being discussed in this thread......the source of these vibrations originates at the wood! It's impossible to measure the vibration at the source, because it's spinning. It's necessary to measure the vibration on the lathe, because it's stationary. Because you feel no vibration at your lathe, doesn't mean there isn't some harmonic flexing of your wood at any given rpm, or any out of balance condition that will cause the wood to flex. No matter how stable your lathe is, it's not going to keep the wood from being a source of these kind of vibrations. :D

-----odie-----
 
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odie

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Ps Using lighter "elasto polymer bands" will increase sensitivity...

I mounted an out of balance blank today, and tried three different types of rubber bands. You're right that the original bands I used, and were the stiffest of the three seemed to absorb vibration, and not show up on the laser pointer. The lightest rubber bands may have been too weak, and may have been the source of some of it's own unique oscillations....(I'm guessing about that) The medium sized bands seem better for the purpose, and a bit more sensitive, without the distorted oscillations showing up in the laser pointer held by the lighter rubber bands.

All this is still in the "experimental" stages, and I have drawn no absolute conclusions.......however, I'm confident I'll be able to use this laser pointer "vibrometer" to an advantage in my turning. This could take some time, and with analysis of several bowls to come to conclusions that will be used to make some rules to turn by! o_O

Thanks again, Clifton......your input is very much appreciated. :D

-----odie-----
 
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