cxs keyless chuck issues

[meikou]

I tend to use the key less chuck on the cxs as I don't have any festool specific bits apart from the bit holder it came with.

I was doing some pocket holes in situ doing our bathroom and I noticed that sometimes the chuck would just rotate instead of opening or closing when changing between drill bits and driver.

I bought it in Jan 13 and it hasn't had a lot of use and warranty isn't an issue but I wanted to find out if anyone here has had a similar thing before I go calling up festool usa?

 

[semenza]

Hi meikou,

Welcome to the FOG!  [smile]

    Not sure what is up with the chuck but I suggest that you call the service department.  You will speak with an actual tech and they are very good about getting things taken care of.   [thumbs up]

Seth

 

[Rick Christopherson]

I have not dissembled the CXS transmission like I have with the C-class and T-class transmissions, but I do not believe that they contain the shaft-locking feature that the bigger drills contain. So what you are experiencing is normal and expected.

The bigger drills have shaft-locking pins to prevent the output shaft from turning by hand. Part of the reason for these pins is to aid in the tightening of the chuck, but the unplublished reason is prevent you from destroying the EC-TEC control module by back-feeding power from the motor into the electronics package, because the motor will quite literally function as a 3-phase AC generator when (if) you spun the output shaft manually.

I've shown these locking pins in several different graphics, but they are the green-colored pins in the image below. They serve to create a one-way coupling so that the output shaft can be driven by the motor, but the motor can never be driven by the output shaft.

The CXS does not contain these because it does not incorporate the EC-TEC electronics that must be protected. To loosen or tighten the chuck, you must rely on the motor to drive the output shaft.

[attachimg=#]

 

[jmbfestool]

I'm curious to how them green pins actually stop the rotation?

Jmb

 

[Rick Christopherson]

I'm curious to how them green pins actually stop the rotation?

Jmb

hehehehe, JMB.....no matter how many times we agree on something, it still doesn't mean I will give you my magical elf knowledge.  [tongue] [poke] [popcorn]

Awww, OK, I give up. The pins get trapped between the pink yoke and the outer casing of the gearbox (not shown). When the motor is driving the output, the pins will be pushed into a position where they fall into a slight recess of the pink yoke. However, if the output shaft is driving the gearbox, then the green pins get pushed out of this recess, and then they bind against the outer casing of the gearbox. This binding is the click you hear when you release the trigger of the drill. The inertia of the keyless chuck will cause the output shaft to momentarily drive the gearbox forward.

By the way, there is a glitch in my graphic that I wasn't going to worry about, but because it is germane to this topic I will mention it. The very bottom green pin is not where it is supposed to be located. It is supposed to be on the other side and shouldn't even be visible in this view.

Edit: Oh, it may not be obvious at first, but the pink yoke is not round. It has little flat spots between the 3 lobes. You can actually see this flat spot under the very top green pin.

 

[AlexThePalex]

The bigger drills have shaft-locking pins to prevent the output shaft from turning by hand. Part of the reason for these pins is to aid in the tightening of the chuck, but the unplublished reason is prevent you from destroying the EC-TEC control module by back-feeding power from the motor into the electronics package, because the motor will quite literally function as a 3-phase AC generator when (if) you spun the output shaft manually.

I don't get this. They engineer a mechanical solution but they didn't think of putting a 10 cent diode in?

 

[Rick Christopherson]

The bigger drills have shaft-locking pins to prevent the output shaft from turning by hand. Part of the reason for these pins is to aid in the tightening of the chuck, but the unplublished reason is prevent you from destroying the EC-TEC control module by back-feeding power from the motor into the electronics package, because the motor will quite literally function as a 3-phase AC generator when (if) you spun the output shaft manually.

I don't get this. They engineer a mechanical solution but they didn't think of putting a 10 cent diode in?

The motor acts as a 3-phase AC generator. A diode cannot block both halves of the AC waveform. So no, you cannot prevent back feeding of power from the manually spun motor into the EC-TEC controller without also preventing the controller from giving power to the motor.

The only reason I know this is because I have torn the motors apart and I was playing around with it by spinning the motor's spur gear in my fingers. I fried the controller in the process.  [scared]

 

[jmbfestool]

I'm curious to how them green pins actually stop the rotation?

Jmb

hehehehe, JMB.....no matter how many times we agree on something, it still doesn't mean I will give you my magical elf knowledge.  [tongue] [poke] [popcorn]

Awww, OK, I give up. The pins get trapped between the pink yoke and the outer casing of the gearbox (not shown). When the motor is driving the output, the pins will be pushed into a position where they fall into a slight recess of the pink yoke. However, if the output shaft is driving the gearbox, then the green pins get pushed out of this recess, and then they bind against the outer casing of the gearbox. This binding is the click you hear when you release the trigger of the drill. The inertia of the keyless chuck will cause the output shaft to momentarily drive the gearbox forward.

By the way, there is a glitch in my graphic that I wasn't going to worry about, but because it is germane to this topic I will mention it. The very bottom green pin is not where it is supposed to be located. It is supposed to be on the other side and shouldn't even be visible in this view.

Edit: Oh, it may not be obvious at first, but the pink yoke is not round. It has little flat spots between the 3 lobes. You can actually see this flat spot under the very top green pin.

That's what was confusing me and I was going to bring up after.  Had an idea of how it works but couldn't see how the third pin would allow for the rotation because it was trapped.  Now I understand.  

Thank you

 

[meikou]

Well I figured I call them up but just wanted to see if anyone here had a similar issue. I've never had this type of thing occur with my black and yellow 18v drill.

I'll give them a bell tomorrow and post up what they say.