Flex-Shaft reving / shaking, defective pivot assembly?

[zeke]

I have a new machine without any modifications, the first time I tried to use it with a basic 1/8" cutting bit for a cross cut, the flex-shaft is shaking to the point where it appears that it would be detrimental to the machin, so I immediately aborted the cut.

It appears that the flex-shaft pivot assembly may be defective. I attached some pics that shows it is not centered in line with the flex-shaft itself. Has anyone else reported an issue like this? Any ideas / suggestions?

[HighTechOkie]

Change the image resolution to 800x600 or smaller and set the color to 8bit. This should bring the size down considerably.

Rob

[Kenm810]

Hi Zeke,

Mine has been off center from one, plus I use the fact that i slightly rotates as the 'Z' moves back and forth along the 'Y' axis.
The off set moves from side to side slowly as the truck moves along the 'Y' axis.
That rotation is part of what I depend on to give my air jet it's sweeping action to help clean the dust and chips
out of the carving and off the surface of the project board, and down through the machine to my DD Cabinet.
The first two photos show the off set before starting the machine,
the third and forth show the off set while the machine is carving plus the end of the Flex-Shaft and sleeve casing.

I think I might check the Flex-Shaft and its end to to see if their damaged, also if it had sufficient moly lubricant.
It worth at least a look. http://www.carvewright.com/forum/images/icons/icon6.gif

[zeke]

Thanks for the pics and feedback. I lubed the flex shaft first thing and it is only a few weeks old. I just inspected the flex-shaft and it looks normal except it just looks off-center when attached to the pivot assembly.

The only time it aligns perfectly is all the way to the left position, anything beyond that is off-center and to the left. I'm going to try taping the wire support loop to the flex shaft and see if that works tomorrow. If that doesn't work, I don't know what else it could be except defective!

Do you have the wire support loop taped to the flex-shaft?

[Kenm810]

In the third photo you can see the Black electrical Tape I use to hold the Flex-Shaft to the Wire Guide Loop; also you will the black tie wrap on the wire loop which may cause hot spots and problems.
It’s not holding anything, I just keep it there to remind me to use it went shipping the machine to Texas.
My machine’s Flex-Shaft sleeve casing is slightly elliptical or eccentric and accounts for it being off center on the Top Hat (Flex-shaft Pivot Assembly)
of the QC Chuck Z-Truck Assembly. You can also check the other end where it’s connected to the Spindle Motor Assembly
I’ve read a couple of post saying one of the screws there came out or was loose.

[mtylerfl]

I have a new machine without any modifications, the first time I tried to use it with a basic 1/8" cutting bit for a cross cut, the flex-shaft is shaking to the point where it appears that it would be detrimental to the machin, so I immediately aborted the cut.

It appears that the flex-shaft pivot assembly may be defective. I attached some pics that shows it is not centered in line with the flex-shaft itself. Has anyone else reported an issue like this? Any ideas / suggestions?

Hello Zeke,


One thing you can check is if the flexshaft receptacle in the chuck is "truly square".

Remove the flexshaft (and any bit you might have in the chuck), then peer down through the top hole in the Z Truck while spinning the chuck (a white piece of paper laid underneath will help you see down through the square hole). If the square hole makes a nice, neat 'circle' while spinning fast, then all is well with the square shaft receptacle. If it appears to make an 'oval' shape while spinning, then it's out of square and that might account for the vibration.

Flexshaft vibration can be also caused by overlubrication. If you have observed any "dark splatters" on your workpiece, then that's a sign that you need to wipe the flexshaft core off to remove excess lube.

[liquidguitars]

what firmware are you using...
I think that firmware Version 1.125 will help smooth out the way the 1/8 cutting bit works.

LG

[zeke]

mtylerfl, in applying your suggested diagnostics, I believe it lead me in the right direction. I didn't see the issues you mentioned, however as I was rotating the Qucik Change Assembly, I thought I'd look at it directly from a horizontal-side view. What I noticed at first was the widest point or lip appeared to wobble as I rotated it. As I continued to rotate and observe, it appeared that a portion of the top of the QC appeared to wobble as well. I have to assume this is my problem and that for the bit to spin at high speeds it must be perfectly square. Could you guys do a check for me and let me know what you see? I did have the flex-shaft out and no bit so it would rotate fairly easily.

I'm not sure if this is a defective QC or if it is improperly aligned somehow. If I need a new QC, do you know if LHR provides the wrench and allen wrench to perform the replacement?

liquidguitars, I'm using version 1.125.

[mtylerfl]

mtylerfl, in applying your suggested diagnostics, I believe it lead me in the right direction. I didn't see the issues you mentioned, however as I was rotating the Qucik Change Assembly, I thought I'd look at it directly from a horizontal-side view. What I noticed at first was the widest point or lip appeared to wobble as I rotated it. As I continued to rotate and observe, it appeared that a portion of the top of the QC appeared to wobble as well. I have to assume this is my problem and that for the bit to spin at high speeds it must be perfectly square. Could you guys do a check for me and let me know what you see? I did have the flex-shaft out and no bit so it would rotate fairly easily.

I'm not sure if this is a defective QC or if it is improperly aligned somehow. If I need a new QC, do you know if LHR provides the wrench and allen wrench to perform the replacement?

liquidguitars, I'm using version 1.125.

Hello Zeke,

I observed the same thing as you did (on both my machines) - viewing as you described, the lip of the QC appears to wobble very slightly as it is spun without the flex shaft attached.

It may be that it's just the lip that is not perfectly horizontal in relation to the part itself, giving the illusion that the QC is "off" - - just my guess.

I didn't see any noticable "wobble" at the top of the QC, though.

Have you had a chance to speak to anyone at LHR yet? I'd be interested in what they have to say about the cause of the flexshaft vibration.

[zeke]

Thanks for taking the time to check for me. Two machines, you must be loving it, well when they are working anyway. I did speak with LHR and was disappointed. I fired up the machine and let them listen to it. The reving even makes the truck assembly shake. The flex-shaft shakes from side-to-side by about an inch and a half span, it's scary. Their response initially was let it run. This is not a slight reving situation, it appears to me that it wouldn't take long for something significant to break such as burning up the motor, flex shaft, damage to the truck, who knows.

After I persisted a bit more, they suggested letting it run until it fails and returns an error message. I'm not willing to do this, it is a new machine and I don't want to end up with a long-term lemon due to excessive and unnecessary vibration, this machine is delicate enough as it is it doesn't need any additional help to break.

This CC machine is the ultimate test of patience and perserverance! I thought about calling LHR back and suggesting a chuck replacement, but then I'd have to buy the tools to swap it out. I wouldn't mind if I had some hours on the machine, but not immediately at the startup. I'm thinking about returning it for an exchange for a new one, it sure would be allot easier to fix that way!

[mtylerfl]

Hello Zeke,

So sorry to hear about your frustration.

I would call LHR back and ask them if they think it could be a spindle problem and emphasize that you do not want to subject the machine any further to the severe vibration that you are experiencing.

I have great confidence in the techs, however it doesn't make much sense to me that someone would recommend you run the machine "until it gives you an error". Maybe the tech didn't fully understand the severity of the vibration that you described here. Of course I'm certainly no expert - it just seems reasonable to me that a power tool should not be run under those circumstances.

If it were me, I'd probably go ahead and send the machine in for repair rather than return it for exchange, and request a thorough test of all machine operations. That should assure that it will come back "even better than new"!

[hotpop]

Zeke,
Disconnect the flex shaft from the z-truck. Rotate the chuck with one finger and feel any bumps or rough spots while rotating. This could indicate a bad bearing. Wiggle the chuck vertically. There should not be any end play. A bad bearing or a loosely seated bearing might be causing your problem.

[zeke]

Thanks for the support! Hotpop, didn't get to try your diags, didn't see the note until after I returned the machine. Sears said I had a machine that had previously been returned and I shouldn't have received that unit. Got another on order!