Flexshaft very hot - again

[scootertrash]

My flexshaft has always been a lot hotter than others describe. Since the first time I used it, in fact. Now it gets so hot it hurts to grab. After a call to support I'm a little ticked off.

Here are the facts:
- Machine is a pup. It has less than 50 hours on it.
- I performed the 25 hour maintenance steps at 24 hours.
- It ONLY gets hot in the MIDDLE, where it bends
- The spindle and bit are warm but not anywhere near what I'd call hot
- Nothing is loose. X, Y, Z are all tight.
- The bit is not loose
- The bit is brand new
- The flexshaft does not have any wires protruding from the ends, in not kinked, i can't see anything wrong with it
- The spring inside the shaft casing looks fine, nothing unusual
- I've re-seated the flexshaft more than once to see if that's the problem. I'm making sure it engages in the motor end and spindle end.
- I lubed it with the penetrating lube CW currently sells online. I followed the instructions in the video to.The.Letter.
- I also followed the trobleshooting steps here, which recommends a totally different lube but I suppose that's outdated: http://www.carvewright.com/support-page/troubleshooting-guide/troubleshooting-the-carvewright/#cut_motor_flexshaft

What's strange is after I lubed it I ran three identical carves - same bit (brand spankin new, first time in machine), same pattern, same wood (poplar). The first carve was hot, the second was what everyone else would say is normal - warm, not hot - and the third was hot again. Hotter, in fact.

I'm fairly upset about the call to support. First question "did you lube it?" Yes. Then I was asked "Well, what do you want to do about it?" I want it to not run hot. Contrary to everything I've read here on the forums the temp mine is running at is a problem however support said "As long as it's not melting the casing it's not too much of a concern." Also, there was no troubleshooting at all. Just "did you lube it?" and then 'You can order another cable if you'd like." No questions about proper seating or wire from it sticking out, etc.

It's not covered under warranty even though it's waaaay below replacement time per the maintenance schedule. I'm pretty well ticked off that the only option is to spend $87.00 on a new flexshaft

Any suggestions? Is there a way to clean the shaft with solvent or something?

I'll probably end up ordering another shaft anyhow because I think there has been something wrong with this one from day one.

69991

[bergerud]

The thing to check is if the flex core is being pushed by compression against the casing in the bend. The core should be "floating" in the sheath. I think this is one of the main causes of heat. My cores protrude about 1/2" out of the truck end of the sheath. Make sure it pulls in and out of the motor end and leaves the 1/2" at the truck end when back in the motor, and that, the core slides easily in and out of the top of the spindle.

[lynnfrwd]

The flexshaft should not need to be lubricated when you get it. In fact, you should rarely need to lubricate it. A new machine will run hot for the first 10 or so hours of use until the spindle gets worked in. I am not sure why yours is particularly hot with 42 hours. I can't imagine that it would need lubricating so soon.

Your list sounds like you know what to look for. I would add to make sure the curvature of the shaft is smooth and not a sharp curve. Also, checking spring for a crimp or a burr on ends of core.

I listened to your conversation with the tech and counseled them on troubleshooting of the flexshaft.

Remember, when you get your new one, it will already have been lubricated.

lynn

[FWMiller]

My flex shaft barely gets warm to the touch. I've got on old A machine with 160 or more hours and I've lubed it once at about 100 hours just because the machine sat for a long time without being used. If yours gets this hot after only 42 hours won't the warranty cover replacement? Sounds like a defect to me.

[DocWheeler]

Do you have the spring-wire support attached tightly to the flex-shaft?
If so, that can cause heat buildup.

I think that I may be in a minority (maybe wrong also) but it seems to me
that there are two places generating heat in the flex-cable, the core and "spring".
The thin lube for the core, in my opinion, does not address the wear area on the "spring".
I have not had a problem with a hot-flex since using the moly chain-lube on the core and
a little moly grease (MolyGraph) on the outside of the core (similar to cam-lube).

[scootertrash]

The flexshaft should not need to be lubricated when you get it. In fact, you should rarely need to lubricate it. A new machine will run hot for the first 10 or so hours of use until the spindle gets worked in. I am not sure why yours is particularly hot with 42 hours. I can't imagine that it would need lubricating so soon.

Your list sounds like you know what to look for. I would add to make sure the curvature of the shaft is smooth and not a sharp curve. Also, checking spring for a crimp or a burr on ends of core.

I listened to your conversation with the tech and counseled them on troubleshooting of the flexshaft.

Remember, when you get your new one, it will already have been lubricated.

lynn

I know you're trying to help me, Lynn, and I appreciate it, but when an expert like you says "not sure why yours is particularly hot with 42 hours" it reinforces my feelings that I got a bum spring from the get go and have (already) shelled out another $87 for a new one.

Edit: Bum shaft, not spring.

[Chris77089]

I have had some customers tell me that their flexshafts run so they have taken a fan and have it blowing across the flexshaft to help dissipate the heat. This may help out with your issue.

[scootertrash]

My flex shaft barely gets warm to the touch. I've got on old A machine with 160 or more hours and I've lubed it once at about 100 hours just because the machine sat for a long time without being used. If yours gets this hot after only 42 hours won't the warranty cover replacement? Sounds like a defect to me.

I was told it is not covered by warranty. And it has always run hotter than what anyone else has ever described. Except the people that have melted them, that is.

I think a free machine is in order :rolleyes:

/not really

[scootertrash]

Do you have the spring-wire support attached tightly to the flex-shaft?
If so, that can cause heat buildup.

I think that I may be in a minority (maybe wrong also) but it seems to me
that there are two places generating heat in the flex-cable, the core and "spring".
The thin lube for the core, in my opinion, does not address the wear area on the "spring".
I have not had a problem with a hot-flex since using the moly chain-lube on the core and
a little moly grease (MolyGraph) on the outside of the core (similar to cam-lube).

The support wire is attached tightly with two bands but it gets hot between the outer band and the end of the support. Burning hot.

I forgot to mention that in my original post.

[scootertrash]

I have had some customers tell me that their flexshafts run so they have taken a fan and have it blowing across the flexshaft to help dissipate the heat. This may help out with your issue.

If my flexshaft starts to run I'll put a leash on it. Couldn't resist.

I don't think a fan will help very much but since I have some carves that need to be done I'll try anything until the new shaft arrives. I was almost considering grabbing some fish tank tubing and a pump and water cooling the sucker.

[lynnfrwd]

Can you post a photo of your flexshaft as it looks connected on both ends (cut motor & spindle)?

Also, did you say you lubed at 24 cut hours or did you mean you soaked it for 24 hours? Describe how you "soaked" it or lubed it, please.

[scootertrash]

The thing to check is if the flex core is being pushed by compression against the casing in the bend. The core should be "floating" in the sheath. I think this is one of the main causes of heat. My cores protrude about 1/2" out of the truck end of the sheath. Make sure it pulls in and out of the motor end and leaves the 1/2" at the truck end when back in the motor, and that, the core slides easily in and out of the top of the spindle.

You've got me thinking - maybe my flexshaft core was made a little too long??

Anyone know exactly how long the flexshaft core should be?

[scootertrash]

Sure, give me a few. I lubed it again 'just because' and this time it's hanging to dry. I was only going to do that for about 5 minutes but had some day-job work to do and got distracted.

I did the standard 25 hour maintenance at 24 motor hours. I did not lube the shaft since it wasn't a line item. I lubed it about 10 or 11 motor hours ago.

When i lubed it I did it exaclty like the guy in the maintenance video. Stuck it on plastic, bloop-blooped lube on it the entire length, wrapped the plastic up, ran my fingers along the plastic to work in the lube. I even twisted it in the slight puddle of lube a few times. Then I pulled it out, let it dry for 5 minutes or so then wiped it down and ruined a perfectly good lint free rag lol.

Lynn, since you're reading this, do you know exactly how long the core should be? I'm really wondering if it's longer than it should be. Maybe y'all could pull one out and measure it.

[lynnfrwd]

Sure, give me a few. I lubed it again 'just because' and this time it's hanging to dry. I was only going to do that for about 5 minutes but had some day-job work to do and got distracted.

I did the standard 25 hour maintenance at 24 motor hours. I did not lube the shaft since it wasn't a line item. I lubed it about 10 or 11 motor hours ago.

When i lubed it I did it exaclty like the guy in the maintenance video. Stuck it on plastic, bloop-blooped lube on it the entire length, wrapped the plastic up, ran my fingers along the plastic to work in the lube. I even twisted it in the slight puddle of lube a few times. Then I pulled it out, let it dry for 5 minutes or so then wiped it down and ruined a perfectly good lint free rag lol.

Lynn, since you're reading this, do you know exactly how long the core should be? I'm really wondering if it's longer than it should be. Maybe y'all could pull one out and measure it.

If I was going to lube a core, I would get a large plastic coffee can and literally soak the core maybe an hour. The coffee can makes the core bend and open up, so that the penetrating lubricant can get inside the core. Then I would let it drip dry at least over night and then thoroughly wipe off any and all remaining lubricant before reinserting into the sheath.

I will go measure the cores.

[scootertrash]

OK, I'll find a can or something and do that and let it drip dry overnight.

I measured it and it's a tiny bit over 37 5/8th"

[bergerud]

It is more likely that the sheath is too short rather than the flex is too long. I would think sheaths are more variable with the glued on ends. Just make sure that the amount that sticks out of the sheath will more than fit into the spindle. (The core gets longer when it warms up.)

[bergerud]

I get about 37 3/4" for all three I have to measure. The old one (750 hr) is a little longer.

[scootertrash]

It is more likely that the sheath is too short rather than the flex is too long. I would think sheaths are more variable with the glued on ends. Just make sure that the amount that sticks out of the sheath will more than fit into the spindle. (The core gets longer when it warms up.)

The sheath will also get longer as it warms up. The coefficient of thermal expansion of plastic is generally much higher than that of metal. For example, plain old polyethylene has a coefficient of 200 M(MxK) while steel is only at 13.

http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

[scootertrash]

I get about 37 3/4" for all three I have to measure. The old one (750 hr) is a little longer.

Wow, thanks. I reckon that core length isn't my problem.

[lynnfrwd]

69993

Core length is shown.

I was also told to get you to check the sheath end at the cut motor to make sure it was still good.

[fwharris]

The support wire is attached tightly with two bands but it gets hot between the outer band and the end of the support. Burning hot.

I forgot to mention that in my original post.

I would loosen up the two bands. What I use is a twisty tie with each end wrapped around the guide wire. It is just to hold the guide wire under the flex core so it can float (mover). I have seen / heard some that had the guide wire tightly attached to the core and the flex shaft would get hot. After doing the above the temp did come down.

[lynnfrwd]

I would loosen up the two bands. What I use is a twisty tie with each end wrapped around the guide wire. It is just to hold the guide wire under the flex core so it can float (mover). I have seen / heard some that had the guide wire tightly attached to the core and the flex shaft would get hot. After doing the above the temp did come down.

That is why I asked for the photo. My concern is whether or not he is talking about the two wide 1"(ish) bands or the twist tie. A twist tie may be too tight.

[scootertrash]

69993

Core length is shown.

I was also told to get you to check the sheath end at the cut motor to make sure it was still good.

Thank you so much. Mine is the same - i was hoping for a slam dunk there lol. Denied.

I'll go check the sheath at the motor end. From what I read all I have to do is twist counter-clockwise and pull, right?

[lynnfrwd]

Thank you so much. Mine is the same - i was hoping for a slam dunk there lol. Denied.

I'll go check the sheath at the motor end. From what I read all I have to do is twist counter-clockwise and pull, right?

I would have to verify counter or clockwise, but yes.

Also, post that photo, please.

[scootertrash]

That is why I asked for the photo. My concern is whether or not he is talking about the two wide 1"(ish) bands or the twist tie. A twist tie may be too tight.

There was a twist tie when it arrived and I removed it per something I read somewhere here, perhaps the unboxing instructions. When I referred to bands I meant the ones you're talking about.

So Ringneck blues man, I don't see a way to loosen said bands - are you saying I should just cut them off and use a twisty? I don't have any of them but I have plenty of other things to loosely attach the guide.

[lynnfrwd]

So Ringneck blues man, I don't see a way to loosen said bands - are you saying I should just cut them off and use a twisty? I don't have any of them but I have plenty of other things to loosely attach the guide.


No, those bands are supposed to be there. We were worried about the twist tie that you said you took off.

[scootertrash]

I would have to verify counter or clockwise, but yes.

Also, post that photo, please.


Photos coming up. I can't get a shot of the sheath in the motor end because there's a ribbon cable in the way

[bergerud]

The sheath will also get longer as it warms up. The coefficient of thermal expansion of plastic is generally much higher than that of metal. For example, plain old polyethylene has a coefficient of 200 M(MxK) while steel is only at 13.

http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

True but the sheath is not plastic. It is spring steel and it would not get as hot as the core. (The plastic is just a coating of no consequence.)

[scootertrash]

700027000370004

I noticed that when the spindle comes to the front of the machine that the support wire puts a pretty firm push on the sheath. Could that be the cause?

[lynnfrwd]

Photos coming up. I can't get a shot of the sheath in the motor end because there's a ribbon cable in the way

Not looking for photo of that end. Just check it out.

[scootertrash]

As much as I could look there i didn't see anything that would get my attention.

[lynnfrwd]

Step back and show a photo of the whole thing. Want to see curve and support areas.

[scootertrash]

Roger. Please hold.

[scootertrash]

Step back and show a photo of the whole thing. Want to see curve and support areas.

Like this? Shots with spindle far right, far left, and closeup of support wire when spindle is far left.

700057000670007

[SteveNelson46]

In your picture there is a white mark on the sheath just before it enters the slot. Is the sheath split there or is that just light reflection?

[scootertrash]

Neither. If you mean the sorta vertical white spot, it was sawdust. If you mean a little below that, it appears to be a touch of excess glue where the sheath connects to the "thing that plugs into the spindle" I have no splits.

[scootertrash]

Here's what's in the picture. The glue looks like something is cracked open in the picture but it's not.


In your picture there is a white mark on the sheath just before it enters the slot. Is the sheath split there or is that just light reflection?


70008

[scootertrash]

Thanks for everyone's suggestions and help.

I'm assuming it's Miller Time in Texas - I need to quit hitting refresh and get supplies for tomorrow's bike night at the American Legion.

Anyone remotely near Buford, GA is invited to come out, totally open to the public, bike not required. Tomorrow will probably be rainy but next week is a large event. The 1st place trophies for the Model Search (hubba hubba) and Bike Show are surprisingly made out of wood ;-) 2640 Sawnee Ave, Buford, just West of the High School. Raffles, prizes, food, cheapest beverages in town <-- shameless plug

/Find the grill and you'll find me

[fwharris]

This is what I was talking about for the twist tie. It just keeps the support wire aligned with the flex core and IMO helps maintain the curvature.

[scootertrash]

This is what I was talking about for the twist tie. It just keeps the support wire aligned with the flex core and IMO helps maintain the curvature.

Im viewing pics on my phone so I may be missing something but that doesn't look at all like the support on my CX.

Thanks for taking the time to post those.

[SteveNelson46]

Have you tried lubricating the core with the lube from LHR?

[CNC Carver]

This is where Floyd was suggesting putting the twist tie.70015

[55president]

I have no twist tie, I guess I discarded it at the beginning. I had a spring wear out at about 400hrs and cause a plastic shaft meltdown. replaced the whole flex shaft and am now at 1200+. I have 2 flex cores and I keep one always soaking in Moly lube in a small cpvc pipe and change them out every 50hrs or so. looking at you photos of your shaft the end closest to the spindle looks slightly off.

[scootertrash]

I have no twist tie, I guess I discarded it at the beginning. I had a spring wear out at about 400hrs and cause a plastic shaft meltdown. replaced the whole flex shaft and am now at 1200+. I have 2 flex cores and I keep one always soaking in Moly lube in a small cpvc pipe and change them out every 50hrs or so. looking at you photos of your shaft the end closest to the spindle looks slightly off.

It sure does but I *think* that's just the sheath looking a little off. That's not where it gets hot, it gets really hot in the middle.

[55president]

I would look carefully at your spring. When my shaft failed once a long time ago the spring was at fault.

[scootertrash]

I would look carefully at your spring. When my shaft failed once a long time ago the spring was at fault.

I reckon I will - at least until the new flexshaft assembly I ordered arrives. I'm irked because it has ALWAYS run pretty hot, except for one carve.

Not too bad to have some down time right now - been running a W1666 DC with 30 micron bags and shockingly have developed a cough. 2.5 micron bags are on the way!

[dbemus]

I strongly support Floyd's suggestion to use a loose flex tie to hold the shaft in line with the guide. I tried that several years ago and it solved a heating problem. Eliminates sharp curve as truck moves back and forth.

[SteveNelson46]

I still have the original flexshaft on my machine that I bought in Dec. 2007 and have lubricated it only about 5 or 6 times. It's still working with about 1500 cut motor hours. It is well known that some of the flexshaft assemblies are of better quality than others even though they all come from LHR so I suggest that you install the new one as soon as you receive it and try to give it a good testing before the 30 day warrantee runs out. Be sure to apply any LHR approved lubricant before you install it.

[lynnfrwd]

I still have the original flexshaft on my machine that I bought in Dec. 2007 and have lubricated it only about 5 or 6 times. It's still working with about 1500 cut motor hours. It is well known that some of the flexshaft assemblies are of better quality than others even though they all come from LHR so I suggest that you install the new one as soon as you receive it and try to give it a good testing before the 30 day warrantee runs out. Be sure to apply any LHR approved lubricant before you install it.

These flexshafts are lubricated by us before we ship them out. There is no reason to lubricate them again.

[scootertrash]

UPDATE:

A few days ago i lubed my 42-hour-old shaft again using what LHR currently sells, bloop-blooped it on just like I did before per the video, but this time i let it dry for two days. The second day of drip drying was incidental because I had no carves pending and I had no immediate reason to install the shaft. I inspected the spring from one end to the other and didn't find anything to raise an eyebrow, but I used a rag and gently 'screwed' the spring through to remove...well, there was nothing to remove but i figured wipe couldn't hurt. Some black stuff came off, i assume it's graphite. Inserted the spring and then shaft the same way i always have and after about 90 minutes of carving it's at a temperature I would call less than MY normal. Warm, perhaps a touch above 'tepid.'

I've only seen this low temp once before, and I believe I described it earlier in this thread - I ran three carves, exact same carve, wood, bit, pattern, ect., and the 1st ran 'normal for me hot', 2nd ran tepid, and third ran crazy hot (each carve around 2:45 long).

Beats the snot out of me why it always ran hot. 42, well prolly 45-50 hours now, no reason to run hot. Unless it's simply my Spanish blood that's the cause (wait, I'm Polish, Irish, and German, not known for hot blood. Or good food)

I have a new shaft assembly on the way but reckon I'll wait to see what my next carve does temperature-wise (I have 6 pending orders).

--------------

On a related note, being the computer dude I am I have some Aurdiono microprocessor borards sitting around and a solid state temp sensor. I very may well tape a sensor to the flexshaft to measure the temp over the time of a carve. Could be interesting. Especially if it sounds an alarm about, say, 451 F, where paper burns (Ray Bradburry said that's the temp)

[bergerud]

I used to wonder if the cores were all wound the same. If one was wound tighter, there would be more internal friction. When you get your new one, compare how easily it bends in a circle compared with the old one. If the old one was wound tighter, it should be stiffer to bend around than the new one.

[lynnfrwd]

If you can twist more than a quarter of an inch, it needs to be replaced.

[unitedcases]

If you can twist more than a quarter of an inch, it needs to be replaced.
Sorry, just to clarify...If I grab both ends with a set of pliers or even my fingers and can twist it? Or just period, if I can twist it?

[lynnfrwd]

In your fingers. More than 1/4".

[bergerud]

It is a quarter of a turn. An old flex can twist with your fingers (clockwise in the same direction the machine twists it) as much as a whole turn. New, they twist less than a 1/4 of a turn.

[scootertrash]

If you can twist more than a quarter of an inch, it needs to be replaced.

Mine barely budges during the twist test.

About to do another carve and see if i can get two 'cool' carves in a row. I meant flexshaft being cooll, ALL my carves are cool LOL

/last carve is going to USMC NCO Academy in Hawaii - woot. Payment is some Marines sending me whatever they felt like throwing in a box. I can NOT wait to see what they send me
//Can it beat my 1960's US-made Israeli steel pot helmet? lol maybe! Marines are a creative lot

[bergerud]

I have a new one here that has not been used at all. With one end in a vise, I can get just (barely) get 1/4 of a twist on the other end with my fingers. If you cannot get 1/4 of a twist, it might support the theory that some are wound too tight. Make sure and compare to the new one when you get it.

[lynnfrwd]

It's supposed to be done held in your fingers. Let's not all force out flex shafts to twist.

[bergerud]

If you do not have a vise holding one end, you cannot tell how much it twists. There would be no reference. The other end you do twist with just your fingers. There is no forcing.

[scootertrash]

Final update:
After lubing and letting the flex shaft dry for two days, AND wiping down the spring, my flex shaft is now running just a little warm like it should. As a matter of fact, it is running gobs cooler than it ever did. I have no explanation for why it was always so danged hot but it's on the second or third carve since working on it and it's no longer hot.

Reckon I now have a spare flex shaft assembly.

[switcher67]

I keep a blower on my flex shaft and it never gets hot

[scootertrash]

A blower would have done me no good. It was crazy hot.