More Flexshaft woes

[gapdev]

Bad Flexshaft or ???

Any ideas on what would cause the motor end of the flexshaft to break lose from the sheath?

I just installed a new Flexshaft to replace the one that melted. I did an Air Carve for 30 minutes and it barely got warm. Then, this morning I started a 7 hour carve. 30 minutes into it, the machine stopped and the outer Flexshaft sheath was hanging from the Z truck, the FFC cable was pulled loose from the Z Motor, and the inner Flex cable was all twisted up into a knot next to the Cut Motor with the end still inside the motor.

The cable doesn't look like it got so hot that the glue holding the end on had melted, but since I wasn't standing there at the time, I can't say for sure.

If the inner cable popped out of the Z-Truck, wouldn't the cable still spin without causing this kind of damage? I say this because of the 2 new Flexshafts that I ordered, both of them only had 1/2 inch of the inner cable sticking out to go into the Z-Truck. I thought this was supposed to be 5/8's and had it only been on one of the cables I would have sent the short one back, but since both were short, I figured this is the way the newer shafts are.

Any ideas are welcomed before I replace the shaft once again and pray this doesn't happen a 3rd time.

This hobby is getting really frustrating (and expensive).

Kenny

[dbfletcher]

This is more of an observation than anything else, and please don't take this in a negative way. It is obvious that you are experiencing reliability issues with you machine. My first machine was kinda like that..... until I got the Rock Chuck, I never managed to complete one project with it with out one error or another. However, with that being said, my confidence level was also about 0% with the machine, so every project I attempted, I sat there and intensely watched every aspect of the machines operation hoping I would see something I could post on the forum that would spark a thought in someones mind and ultimately lead to a permanent solution. I realize you would like to be able to start a project and walk away (never a good idea, but I routinely do that now that my machines seems to be pretty much trouble free), but until the issues are sorted out... it is hard to understand how you are not watching it very closely until everything is sorted out.

I definitely feel for you... having a machine that doesn't work right is no fun. No fun for you, no fun for LHR, and no fun for the rest of us to have to share your pain with you.

[Digitalwoodshop]

Someone posted a picture of a coiled up inner flex inside the machine a few weeks ago..... I don't remember what the outcome was of that...

Are you Hogging the Wood... Taking a BIG Bite? Using Normal Mode on hard wood when you would be better to use Best Mode for a slower feed rate....

More input....

AL

[gapdev]

Hi Doug,

Had a Rock Chuck on the machine. Replaced it with the CarveTight because I thought I may have damaged the spindle getting the QC off and it was the cause of the Shaft getting hot.

I did a test carve yesterday after installing the new Flexshaft and fixing the broken/smashed LCD cable (which was done in manufacturing) and let it go for 30 minutes, all the while standing there watching and taking temperature measurements. All was well.

There's just no way that I can stand there and watch the machine for a 7 hour carve. I didn't buy the machine to become a slave to it. I do have a Video Camera watching it and I was watching the video when the Shaft broke and the machine stopped. So I may have gotten to the machine no more than 1 minute later than had I been standing there.

Attached is a picture of the new Flexshaft compared to the one from my C machine. The one on the left sticks out barely 1/2 inch. The one on the right is just under 5/8 inch. Don't know if this has any bearing on the new shaft breaking down.

The one thing the new Flexshaft is not doing that the one that melted did, is it is not vibrating and shaking. So, that is/was a good sign. That vibration was a warning that something bad was about to happen - and it did.

This was a brand new cable. It went into the motor at least 5/8 inch (leaving less than 1/2 inch for the Z-Truck). Shouldn't we have some expectation that a new cable will last longer than 30 minutes?

One thing that isn't clear with the Installation instructions. Is the Flex Shaft (sheath) supposed to turn (move) when it is in the motor and the screw down to hold it in place? Or is it supposed to be tight and immovable? I'm thinking it needs to turn as the Z-Truck moves back and forth across the Y axis.

I'm just hoping this was a one time incident with a bad glue job because when I went to pull the remaining sheath out of the Z-Truck, that end pulled off as well, telling me it wasn't glued very well either.

But I don't know. It's hard to know what is normal and what is not without years of experience like a lot of you guys here have.

Kenny

47947

Kenny

[gapdev]

Al,

I posted a picture a couple of weeks ago of my coiled up shaft after the sheath melted. The outcome of that incident is this one.

I was carving a 13.5 inch 1 piece Dial for the Naked Clock in Maple, using the Optimal setting (7 hours). I haven't yet used the Normal mode for anything - everything I've done has been using Optimal.

What did get carved was nice and smooth.

Kenny

[Digitalwoodshop]

Kenny,

Well you are doing all the things in the best way.... This has me stumped....

AL

[lynnfrwd]

Kenny:

Did this "meltdown" or "knotting of the core" happen on two different machines? Or the same machine? Your B model or your C model?

How long have you been using the Cranes Cam Lube? Is it grease or oil?

You mentioned your flex has loose from your machine and had possibly come "unglued". Was this when it "knotted" or a result of it "knotting" or earlier in the day? On your first "meltdown" the sheath is loose from the machine too. Did this happen before the "meltdown" or as a result of it?

You ordered several parts yesterday around and before lunchtime. Are these for the C model or the B model? Was it prior to the second meltdown?

You displayed two different flexshafts in the photos (one 1/2" extra and one 5/8" extra). The cores that "knotted", do you know if they were the shorter or the longer of the flexshafts. Do you know if it is the sheath or the core that is a different size?

Sorry for all of the questions, but we are trying to figure this out....get execs pacing around and scratching their heads!

I tried to give you a call, maybe you can call me when you get a chance.

Connie

[gapdev]

Connie,

Didn't receive any calls today. You may have called when our Electricity was out (thank you SDG&E). Later: Ah, Cell Phone. It was busy installing iOS 5 and updating itself so I missed some calls.


Did this "meltdown" or "knotting of the core" happen on two different machines? Or the same machine? Your B model or your C model?

This was not a meltdown this time. It was a disintegration of the FlexShaft. On the B machine. Same machine as the prior meltdown.


possibly come "unglued". Was this when it "knotted" or a result of it "knotting" or earlier in the day?

Don't know the cause. Whether it came unglued while it was twisting up, or it came unglued first and then twisted, don't know. The end that goes in the motor was still in the motor, the sheath that is glued into that end was dangling lose outside the machine.


On your first "meltdown" the sheath is loose from the machine too. Did this happen before the "meltdown" or as a result of it?

On the first meltdown, the sheath literally melted. The meltdown is what tore that sheath apart.


You ordered several parts yesterday around and before lunchtime. Are these for the C model or the B model? Was it prior to the second meltdown?

And I was hoping to have them by Friday but they haven't been shipped yet. These parts are for the B machine. Since the C machine is under warranty for at least the next year, I'll not do anything to it unless instructed by a Tech and hopefully it won't need any repairs :rolleyes:. The parts were ordered after the second shaft fell apart. I don't know if the motor is causing this or what so I just want to play it safe (even though the motor looks fine and it could have just been a bad shaft).


You displayed two different flexshafts in the photos (one 1/2" extra and one 5/8" extra). The cores that "knotted", do you know if they were the shorter or the longer of the flexshafts. Do you know if it is the sheath or the core that is a different size?

The short core is from one of the new shafts I bought a couple of weeks ago. I put this shaft on the B machine and it knotted and ripped apart within an hour.

I don't know which is shorter since the core is all knotted up, but both of the new shafts that I ordered look identical so I'll measure the core in the other new one I have (it too is shorter than the one in the C machine) to see which is shorter, the shaft or the sheath. Basically, all that is left to go in the Z-Truck is a bit less than 1/2 inch. This is true for both of the new shafts I received. I ordered another shaft and it will be here Friday. We'll see how that one compares to the one in the C machine as well.

For what it is worth, the spring in the shaft that disintegrated is in excellent shape. I wouldn't hesitate to re-use it and keep it as a spare part.

The end that goes in the Z-Truck was still attached to the sheath until I went to pull it out of the Truck. That is when it tore lose from the sheath. Looking at the pictures of that end (with the Red circles) you will see that the rubber/plastic is cracked and somebody tried to glue it. It was like this when I got it. In fact, both ends had excess glue on them.

I will measure the other new Flex Shaft core tomorrow and get back to you.

Kenny
4799347994479954799647997

[gapdev]

How long have you been using the Cranes Cam Lube? Is it grease or oil?

I used it once and wasn't really all that impressed. This was back before the original meltdown. I was trying to see if I could get the shaft to run cooler. The Cranes didn't appear to help and it tends to gunk up the inside of the sheath.

The Cranes is a paste. I don't see how it can get inside the core like the liquid Chain Lube does. I may try it again later.

On this particular shaft that fell apart and knotted up, I didn't put anything on it since they are supposed to already be lubed.

The one on the left is the one that knotted. Notice how shiny it is compared to the one on the right (C machine) which is a gold color. Would that indicate it hasn't been lubed? It didn't get hot, but then it only ran for half an hour before falling apart.

Kenny

47998

[gapdev]

The one on the left is the one that fell apart. The one on the right is from the C machine. The one on the left is noticeably shorter (less than 1/2 inch sticking out). Note: Picture was taken before it fell apart.

48003

This is the other new shaft that I bought at the same time. It looks identical to the one that fell apart. The other end is in the motor all the way. Only 3/8's left for the Z-Truck. Something tells me I should not use this shaft.

48004

This is the sheath from my C machine. Looks to be the correct length.

48005

This is the core from my C machine inside the newly purchased sheath. Notice that it is now too short.

48006

Compare the cores. The new one seems to be more loosely wound although it passes the pull and twist test

48007

Although I haven't measured the new sheath and compared to the C sheath (it would be difficult to measure accurately), it seems as though the new sheaths are longer which makes the cores shorter (because they remain the same length).

I don't know if this is leaving enough of the core for the Z truck or if the core is pulling out and then twisting up inside the sheath (can it even do that?).

But, both of the new shafts that I purchased are like this and I'll know tomorrow if the 3rd shaft I recently purchased is the same. I'm now reluctant to use these shorter shafts until I get the go ahead from LHR.

Kenny

[chebytrk]

48007[/ATTACH]

Although I haven't measured the new sheath and compared to the C sheath (it would be difficult to measure accurately), it seems as though the new sheaths are longer which makes the cores shorter (because they remain the same length).

I don't know if this is leaving enough of the core for the Z truck or if the core is pulling out and then twisting up inside the sheath (can it even do that?).

But, both of the new shafts that I purchased are like this and I'll know tomorrow if the 3rd shaft I recently purchased is the same. I'm now reluctant to use these shorter shafts until I get the go ahead from LHR.

Kenny

Looking at the "new" sheath in the picture it appears to have some small gaps in the winding compared to the "C" sheath. I wonder if that's enough to make a difference and cause problems.

[gapdev]

it appears to have some small gaps in the winding

That was my impression when I first looked at it and compared it to the C core. It seems to be more loosely wound. Not sure what impact that would have on performance.

Kenny

[grinanbarrett]

I just had this happen tonight to me, although not quite as "traumatic" as yours. I was standing with my machine, that I just finished loading the new Carvetight spindle on, and noticed a severe "vibration" accompanied by a loud shrieking sound, that scared me bad enough that I hit stop. When I started investigating, I see that my flexshaft, that is practically brand new, less than 4 hours, has come apart. The outer sheath on mine has separated at the cut motor end, leaving the small plastic end cap that fits in the cut motor still attached .

I am very curious as to what has caused this. I did not have the sense to measure the length of my shaft when I installed it, so I can't comment on the length compared to the old one.

Mine is a B machine, Melted a flex shaft about 3 weeks ago, installed new, noticed looseness in the quick chuck soon after that, within an hour. Replaced the old chuck with new carve tight. This was my first carve with the carve tight.

I too can see where there was glue applied to the plastic cap, and that appears to be what failed, the glue.

What was your outcome?

[bergerud]

You should contact LHR. They will probably want to see the broken joint.

[gapdev]

What was your outcome?

I sent my Flexshafts back for examination (the melted one and this new one that fell apart). I believe they received them yesterday, haven't heard back and wasn't really expecting anything.

It sounds like we had pretty much the same problem. Melted shaft, install new shaft, new shaft came apart. The end of mine tore off the shaft just like what you describe.

I now have 3 new Flexshafts to try out ($225 worth of shafts) and a new (rebuilt) motor and a new FFC cable, just in case. Haven't yet had a chance to install a new shaft after this last fiasco (just received all the parts, took a bit longer than expected). To be honest, I'm a bit afraid. Guess I'll install and park myself at the machine while the machine carves something.

I have to wonder if there isn't a bad batch of flexshafts floating around. I've got 3 new ones and they all look the same (slightly different than the one that came in my C machine).

The core in all 4 is the same length, but the sheaths on the 3 new shafts are longer. This makes the cores appear shorter to the machine (less of the core to go into the spindle), but I was told that this should not be an issue.

Kenny

[grinanbarrett]

Thanks for the update kenny, I ordered two new ones tonight, This is most definitely turning into a very expensive "hobby".

and yes, I will attempt to contact LHR on monday, if my work schedule allows.. and see if they are interested in examining this one. I have to agree with you in the thought that there may just have been a bad batch of them floating around.

Many more bad flex shafts, and I may have to resort to carving with my pocket knife... and that's not nearly as fun.

[dltccf]

These flexshaft issues are frustrating. I haven't been able to use my machine since August because of my own flexshaft woes. Spent weeks having them send me new flexshafts then new cutmotors. Finally when a brand new shaft started to develop twists in it as though it was going to knot, they asked me to send the whole machine back. That was two weeks ago. It took a week to get to them, then a week for them to analyze it and hopefully they will ship it back on Monday so in only another week maybe I can start carving again. I am concerned that all they found was that the truck was getting hot and needed new bearings. It always ran at around 116 degrees for me even when the shaft got up to almost 200. In the conversation, the tech mentioned the shafts made locally and the ones they get from China, so there is definitely the potential for a bad batch.

I wouldn't be that concerned about the shafts being too short. Mine were about like the one in your picture which you describe as normal and they were concerned that mine could be too long and because they get longer when they expand because of the heat it could have gotten too long and expanded down into the truck and damaged the bearings.

dave

[ibewiggin]

Very frustrating in deed. My machine has been down forever! One thing that I noticed about mine, was that it actually ran fine while carving in the normal back and forth motion, it was hotter than the other machine, but not too hot to touch. Now when the belts started moving the project through and it would carve a line, in the x direction I believe, that is when it would shake and get hot. Can anyone confirm the same behavior? It may just be coincidence, but that is the only thing I can figure is different between being hot, and melting.

[sail]

after reading the bad flex shaft issues, I'm wondering if the direction of the coil that is, twist on the shaft, is backwards? That might make them unwind under service tension. ?? Maybe ?? I can't tell from the pictures if this applies.

[bergerud]

Think of a threaded rod. A nut will thread on either end. Left or right handedness is not changed by flipping ends.