Flex Shaft Vibration Video

[deemon328]

I posted a video on http://www.youtube.com/watch?v=9eiHdul5tC0 demonstrating abnormal vibration on the flex shaft when using the 1/8" straight bit.

From the info already on the forum, I discovered this can be caused by:


Over-lubrication or under-lubrication of the flex shaft or possibly wrong lubricant type
damage to the flex shaft square ends
wear on the chuck making the square hole elliptical
bearing issuesThe only issue that I may have is a little over-lubrication of the flex shaft, everything else looks fine. I carved 2 1-hour projects this morning, and paused and wiped down the flex shaft after 20 and 40 minutes because I noticed some excess splatter on the board surface. I wiped down the shaft again at the start of my second carve and didn't see any overspray or other indication of over-lubrication still existing, yet, I still had this vibration problem.


Has anyone heard of an adjustment process or other steps that can be taken to eliminate the vibration?

Is there a possibility of too much lubricant pooling on the back end of the flex shaft inside the machine?

[Kenm810]

Hey Dustin'

You didn't happen to see a sliver colored, curved corrugated, strip of metal like the ones in the photos below.
I was told by one of the LHR techs it's a bottom bearing guide from around the "Z " truckshaft where the QC chuck connects to the flex shaft.
I've had two work their way out and can cause all kings of vibration and bit wobble along with a change in carving sound of the machine.
The first time I found it still hanging on the shaft, the second one I didn't see until I look in the bottom of the machine.
I really don't know if this has anything to do with your machine problem, but I thought I should mention it to you.

[TerryT]

I haven't read every post in this thread so this may be a silly question, but...
Is the spring insert still in the flex cable. I know some folks acidently put it back together without the spring before.

[deemon328]

Thanks for the pictures and the comments. I could not see that little metal strip at all, but normal carving sounds don't seem to indicate any problem.

I might have a little calibration problem because all of my part cut outs on my latest puzzle carving aren't perfectly sized, but I'm not experiencing any bit wobble or other sound changes, so I'm not attributing those errors to the vibration. In the video, you can hear the normal running sound vs. the vibration sound. I swear I can see the loss of power in the bit due to the flex shaft vibration; it looks like the bit goes slower, but it might be my imagination.

I've really tried to lock down the machine vibrations. I clamped the CW to the table, and I'm considering bolting the table to the floor for that final guarantee to reduce as much vibration as possible.

I don't get why the vibration is sporadic like that. If it was somehow not connected properly, I would think it would vibrate all the time. I'm tempted to open up the machine and check out the internal flex shaft connection, but everything else is working so well right now, that I'm not sure it's worth it. One thing is for sure, that vibration has to be causing undue wear somewhere.

[deemon328]

Yep, the spring is still in the cable.

[mtylerfl]

Hello deemon328,

It appears that the flex shaft starts to vibrate severely when the truck moves along the y-axis. I had exactly the same problem on one of my machines. I sent the machine in for repair and it has been absolutely perfect ever since - zero flexshaft vibration and the truck glides sooo smoothly!

I was told by an LHR Tech when I originally reported my vibration problem, "That indicates that your spindle is out of alignment and needs to be replaced".

I don't really know exactly what part(s) was actually replaced, but they took care of the problem lickety-split. Works better than ever now.

[deemon328]

Thanks for the input! Did you have the problem on the carving bit as well, or was it just the 1/8" cutting bit?

Now that I think about it, when carving operations take place, there's not really much Y axis movement at one time, so the problem wouldn't be evident.

How was your turn-around time? I'm really fired up to have it working after the Z-axis replacement part wait and the re-soldering of the L2 coil behind me. I can see how once you get a smooth working machine how nothing could pry it away from you.

[mtylerfl]

Hello,

There was indeed some vibration when carving, but it seemed most severe when it was doing cutouts (with the 1/8" cutting bit, as you mentioned).

I recall the turnaround was very fast - less than two weeks from Georgia to Texas and back. Was well worth the wait, as the machine is performing flawlessly ever since I got it back.

[Dirtydan]

deemon328,

My machine has done that since day-one. I've noticed it seems to be caused by one or more of the the following:

1. Wood being carved
2. Direction of the grain being carved
3. Depth of the cut pass
4. Bit sharpness
5. Speed of the cut (Nothing you can do about this)

What I've seen is that the osicollation will always be in the same area on the board once it starts. Every project seems to be different, so I tend to think it's mostly realted to the grain pattern of the wood in that paticular area. I've had this problem not only with the 1/8 cutting bit, but also with the Ogee bits too.

I use mostly Oak, but I've notice that the occurance of the oscillations seem to be linked to the board being carved... and not just one of the above... I have done up to three or four project, without any oscillations.

You can monitor the cable temp because both under and over lubrication can cause heat build-up and in theroy will reduce the life of the flex-cable, but if that was the cause of the oscillations, the oscillations would be constant, reguardless of the bit being used.

[TIMCOSBY]

machine did this on both directions all the time and had that ascilating sound. totally diff than my first machine which i still have. the second one had all kinds of gremlins too so i took it back.

[Dirtydan]

Tim,

When you get your new machine try running this project... If the oscillations occure, make to note on which bit and where on the board and the direction of the cut...

The file is in the 1.125 format


machine did this on both directions all the time and had that ascilating sound. totally diff than my first machine which i still have. the second one had all kinds of gremlins too so i took it back.

[ruggybear]

I have seen this problem with the 1/8" cutting bit when used on bad wood. In my case it was pine that was just a junk piece and contained enough moisture that the cutting bit was not cleaning out the cutout that it was making. This caused the bit to need more pressure to get through and the cable made a horrible sound and broke the bit.

The carving bit worked ok. It was just the cutting bit that showed the problem.

Ken

[Dirtydan]

Well you know you should SPANK that BAD wood.... BG!!!

I've never had a bit break but there more than a couple of times, I felt it would be safer in the house. LOL...

The moisture could be a major factor...I don't think that was the case for me, but you never know.... one part of the wood could have had a little extra moisture in it there by making the bit work a little harder...


I have seen this problem with the 1/8" cutting bit when used on bad wood. In my case it was pine that was just a junk piece and contained enough moisture that the cutting bit was not cleaning out the cutout that it was making. This caused the bit to need more pressure to get through and the cable made a horrible sound and broke the bit.

The carving bit worked ok. It was just the cutting bit that showed the problem.

Ken

[TIMCOSBY]

Tim,

When you get your new machine try running this project... If the oscillations occure, make to note on which bit and where on the board and the direction of the cut...

The file is in the 1.125 format

just adding a second machine. still have my first one. the second one had so many gremlins i took it back for a refund. my first one does not make that oscilating sound like the second one did. i even tried them side by side with the same project.

[deemon328]

I hadn't considered moisture content of the wood. Most of my wood is self-cut and air-dried to random amounts. The maple in the video is among the least dried, since it's only been air drying for a little over a year. I still had the problem with some kiln dried cherry, but IIRC, the vibration wasn't as much a problem.

Dan, you do a lot with your machine. Have you had any noticeable ill effects with it since you've been living with the problem?

Thanks for all the input everyone.

[mtylerfl]

Dustin,

I do not think your problem is caused by "bad" wood or any of the other odd and ends mentioned, at all.

The machine has an obvious alignment problem causing the vibration, and it needs to be repaired. Call LHR and get the machine fixed. You'll be glad you did!

[Hexe SA]

I agree, get it fixed, call today and attach a paper with a link to the video. I'm on machine # 2 and never seen this that bad. Occasionally I have a small vibe, but only if it hits a flaw in the wood which is about 1/2" or bigger.
Eva

[TIMCOSBY]

moisture content too. i have used wood staight of the sawmill, doesnt get much wetter than that.

[deemon328]

I spoke with LHR techs this morning. They watched the video. We took the flex shaft out and I held it straight and tried to twist it. There's less than 1/8" at most of rotation, so that was considered normal. We checked the square hole for eccentricity--also normal. I took the flex shaft completely apart at the cut motor and checked for extra lube--no problems.

Ultimately, the tech suggested two things. First, that the vibration can occur in harder woods, since I was using maple in my video. Second, if the sound of the carving changes, then replacing the QC is the solution.

I just finished a test in pine of one of my picture frames. There was no vibration during the carving. There was the same vibration in the video when doing the cut path. It happens not just on the Y-axis travel, but also on X-axis travel going away from the touchpad. As the bit travels along the x-axis back toward the touchpad, the vibrations stop.

I'm out of 'wait on hold' energy for today, but I wanted to share the tech's support info with those who might also be having this problem.

[Ivanq]

My carving experience yesterday was nightmare! One of the things that went wrong is something I had seen before on a similar carve. When using the ogee bit cross grain the shaft would vibrate and the carve would then have a 'washboard' in the channel it was cutting. Yes, I could spend the time to hand sand the 'washboard' out but I would prefer the it didn't occur at all.

Has anyone else had this problem? Solution???

I had a bunch of other problems occur after I upgraded to 1.25 but I'll first check if it's something I'm doing wrong.

Cliff in Roswell

[mtylerfl]

...First, that the vibration can occur in harder woods, since I was using maple in my video. Second, if the sound of the carving changes, then replacing the QC is the solution.

I just finished a test in pine of one of my picture frames. There was no vibration during the carving. There was the same vibration in the video when doing the cut path. It happens not just on the Y-axis travel, but also on X-axis travel going away from the touchpad. As the bit travels along the x-axis back toward the touchpad, the vibrations stop...

Hello,

What you describe is EXACTLY the problem I had (it vibrated violently when nearing the keypad side of the machine - vibrations diminished when moving away from keypad side). Sent the machine in, got it back, better than ever - NO vibration of the flexshaft ever since.

You can see my original post that describes what I experienced...
http://forum.carvewright.com/showpost.php?p=30356&postcount=1

[Dirtydan]

Deamon,

Like I said before... My machine has done that since day-one. It doesn't happen on every project, with every bit, on every kind of wood, or in the same direction or path area on different pieces of wood. When it does start, it's always in the same area on the board. On some boards it happens when I'm carving a cross the grain, others with the grain, sometimes when the wood is moving backwards or forward, other times when the chuck is moving away from the keypad and then on another projects when the chuck is moving toward the keypad. Bottom-line, I've never seen evidence of the bit dancing as a result of the flex-cable dancing/vibration. Sometimes you will also notice a burning on the wood, which could have many different causes.

I watched the bit during the carving (Vibration) and did not see any signs of excessive movement. When the project was done, I checked the wood for signs of bit chatter or other damage that might be caused by excessive bit movement. None was found other than some burning on the wood, I didn't see anything. I sharpened the bit and moved on. I’m getting close to 200 hours on the machine, (knock on wood) things are still coming out the way I expected they wood. Yes, I still get the Flex-Cable Dancing/Vibration, but the truck, chuck and bit appear to be right on the money relative to the carving.

[DrBob]

Hi dirtydan
You said that you sharpened your endmill, do you do this yourself or do you send them out?
Sharpening should be done professionaly on the proper machine. Also, have you noticed if the vibration is coming when the machine is doing a climbmilling for this is a lot harder on the bit...and..if the bit is dull will cause vibration.

Bob

[Dirtydan]

I'm sorry for leading you that way, but I've never sharpened the cutting bit. I buy a new one...;)

The bit that causes me the most vibration/cable dancing it the 3/8 Ogee... That's the one I sharpen, sometimes just clean-up is all that's required. I use the standard diamond flat files you can get at most wood working stores..


Hi dirtydan
You said that you sharpened your endmill, do you do this yourself or do you send them out?
Sharpening should be done professionaly on the proper machine. Also, have you noticed if the vibration is coming when the machine is doing a climbmilling for this is a lot harder on the bit...and..if the bit is dull will cause vibration.

Bob

[Cmdr.Rav]

Dustin, you might want to check your bit chuck to see if it is loose. The quick release chuck screws in and will make the flex shaft vibrate. Not to mention through your bit and mess up your Z truck!

Rav

[DrBob]

I'm sorry for leading you that way, but I've never sharpened the cutting bit. I buy a new one...;)

The bit that causes me the most vibration/cable dancing it the 3/8 Ogee... That's the one I sharpen, sometimes just clean-up is all that's required. I use the standard diamond flat files you can get at most wood working stores..

When you sharpen the ogee's edge do you just try to get the cutting edge sharp again?
Because when you sharpen any cutting tool you have to have a releaf from the cutting edge backwards.
which means the cut edge has the highest point and the rest of the blade tappers below it's hight.
Sometimes it is hard to see. but it has to be their or you are pushing the removed material against the wall you just cut which will cause burning, vibration and excessive wear to the just sharpened edge.

[zeke]

I just returned a brand new machine with excessive vibration. Feels like a manufacturing defect reading all these posts. Shouldn't happen on a brand new machine. Based on reading these posts, I'm surprised LHR wasn't aware of my problem when I called them about a week ago based on mtylerfl's comments about sending the machine in and other posts here.

LHR's recommendation was to just run the machine until it fails (humm) and then give them the error code. However it was not failing after a few minutes. I was not planning to follow that recommendation, too much strain on the delicate machine! My vibration was more constant than the one in the video and at times much worse.

You know working on the machine has really made me familiar with much of the machine. However I'd rather have the experience designing and carving!

Got a new machine today, haven't had a chance to run it yet. Hopefully this machine will yield some projects. I keep staring at the white towel ready to throw it in, on some days have had it my hand, but have a hard time giving up!