Does your T15 drill "Clunk?"

[Iwood75]

Today, I went again to my dealer to return the CXS and "handle" the T15 and C15 to decide which would replace it. The T seemed better balanced. However, it made a disconcerting clunking noise when the switch is first engaged and again when released. The C did not. Is the clunking noise a normal sound for the T15?

Because of the T's noise and ssuming that I will get used to the C's configuration, I came home with the C15. Now, I've discovered that the C does not have a lock position (or at least this one doesn't) when the switch is halfway between forward and reverse. When midway, it still runs slowly forward. Does this signal a soon to be broken switch? And please don't remind me that I can return it, etc. I've already made 3 one-hour trips just to get this far. And what's with the bit "wiggle" when using the Centrotec chuck?

 

[Brice Burrell]

Did you have the keyless chuck (without a bit) on the T15 when you were getting the sound?  The keyless chuck will make some noise at start and stop with no bit in the chuck. 

There is some runout or wobble in the Centrotec bits.  Since you already had the CXS you should have an idea if your new one is defective or not. 

Someone correct me if I'm wrong here, but, I think there is no definitive lockout on the Festool triggers.  If you try to squeeze enough you can override the lockout.  I'm not completely sure since I have no use for a lockout feature.   

 

[peter halle]

if I remember correctly the center portion is not a lock out - just no man's land.  If the trigger is depressed it might go one way or another.

Peter

 

[ScotF]

That's correct.  No lockout on the switch.  I have never had a need for it so never really worried me one way or the other.  I agree with Brice that the sound could have come from the chuck.  That happens on a different manufacturer's drill I have...

Scot 

 

[BravoRomeo]

My CXS has a center detent position on the direction switch that positively locks the power off. My C15 does not have a center detent position, and if you leave the reverse switch mid-way, it sort of prevents use, but you can still get some movement. I think the center-off is unique to the CXS.

 

[Iwood75]

I tried the T15 only with the Centrotec chuck and no chuck. The sound definitely emanates from inside the drill. It sounds like what I call "gear lash." Like loose fitting gears that clunk against one another at start and again when the drill stops. Do your T15s make this sound? Or, is it safe to assume that this drill has an abnormality and have the dealer order in another one for me? My concern is that my 30 day period is running out.

And strangely, that particular T15 does have a definite mid-position lockout. Only the light turns on when it's centered.

Thanks for helping me resolve this issue.   Joel

 

[Brice Burrell]

The clunk dosen't sound right to me.  I suppose there is a chance it is caught between gears. 

 

[Rick Christopherson]

As was mentioned, there is no center position lockout. What seems like a lockout feature is actually just a tab on the forward/reverse button to prevent you from changing direction while the trigger is being pulled. It's been too many years since I played with the controller, so I can't remember what happens when the controller senses the change in direction while the motor is in motion. Either it ignores it, or it error's out and shuts down.

Secondly, there is no forward/reverse switch. There is a hall effect sensor embedded inside the controller and the button simply moves a tiny magnet toward or away from this sensor. The button is the green piece sitting by itself in the center of the picture below.

The clunking sound is most likely just the shaft locking pins (green pieces in the image below) moving into and out of the locked position. These three pins lock the output shaft for changing bits. They also prevent the motor from being manually turned by the chuck, which would result in it becoming a generator and backfeeding an electrical signal into the controller's output transistors. There is no perceptible lash in the geartrain. It is a 3-stage planetary set, and you could never notice the lash of any single gear.

 

[AlexThePalex]

The clunking sound is normal with the T15, it's the electronic brake kicking in. Probably those green pins Rick mentions above.

 

[jmbfestool]

I only get the clunking sound when I have the Jacob chuck in any other chuck centrotec or right angle etc dont make the clunking.   It only happens at low speeds so when starting and stopping.

 

[sean_hogan]

Mines is exact same as JMB checked it today, only with Jacob chuck

 

[Rick Christopherson]

Mines is exact same as JMB checked it today, only with Jacob chuck

This is due to the inertia of the relatively heavy jacobs chuck. (Technically it is not a jacob's chuck, but only my father would lecture me on that point.  [tongue])

Due to inertia, at start-up, the rest of the gear train will rotate a small portion of a revolution before the locking pins are driven to their free position. At shut down, the reverse happens, as the pins get shifted to their locked position.

It is complicated to explain, but the light pink, 3-lobe piece is only loosely coupled to the 6-pin hub to its right. The two of them will have a 1/12 (revolution) lash angle, which is what cases the green pins to either be in their locked or unlocked positions. The top green pin is in the unlocked position, and the bottom green pin is in its locked position. In their locked position, they jam against the outer casing of the gearbox.

 

[Iwood75]

Concerned that the clunking sound warned of an impending problem, I had disregarded the T.  However, thanks to your really helpful replies and to you Rick for your illuminating technical explanation, I'm no longer worried.  Maybe I won't even hear it after a while.

So, I've spoken with Brian at Capital Building Supply and he advised me to give the C15 a good workout this weekend. He predicts that once I get accustomed to the C configuration, I'll prefer it.  If however, I still prefer the more familiar (to me) T style, we'll swap next week. 

Thanks again to all.  Joel 

 

[Iwood75]

An update:

Well, I exchanged the C15 for the T15 and it WAS the right move!  I find, the "T" style to be much better balanced – which also makes it feel lighter – than the "C."  Today, I used it for about 4 hours – pre-drilling and driving around 180 screws into hard maple... and the fuel gauge still reads 2/3 of life left.

AND, my new T15 does NOT "clunk."  [thumbs up] 

Thanks to all for your very helpful input into my decision making process. You came through for me again.

Joel