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



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 . 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

[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

[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.



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.



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



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



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



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