TS75 Start Up Vibration ???

[bholt]

Have a many years old, but near new TS-75 that will now be used much more since my recent retirement. I inadvertently nicked the aluminum MFT3 table surround on a plunge start. Now, every time I start it there is a loud audible hum and vibration until it reaches the set rpm, then smooths out and cuts just fine. Vibration isn't that strong, but the accompanied hum is and this saw normally runs smooth as butter. Thought I might have damaged a tooth, so bought a new Festool replacement blade, but it didn't fix the problem.

The problem goes away as soon as saw reaches the set RPM and even if you have the saw spinning at a low speed (3-4) and and increase the speed setting using the dial you get the same momentary vibration/hum until it reaches the set rpm. So, it appears to have the problem under load spinning up. Since these saws can be used for cutting aluminum with proper blade I'm a little surprised nicking the table cause this problem.

Hoping maybe this isn't as serious as it might be like a bent shaft or bearings, but it certainly needs repair.

Any thoughts on this?

Butch

 

[sancho57]

Have you checked the blade for a chipped /broken tooth?

 

[Birdhunter]

Called Festool yet?

 

[RKA]

I think you're probably on the right track.  You've eliminated the blade, cut quality hasn't diminished and it does smooth out once it's at speed, so you probably didn't damage the arbor.  But your last comment about adjusting the blade speed and noticing the same issue you see at start up suggests you're onto something.  Something with the blade speed or sensor feedback mechanism to the motor possibly? 

The only thing I would suggest, when sending it in, talk to someone and explain what happened and this hum and vibration is different from the usual growling of the MMC electronics.  You just want to make sure it's not quickly dismissed as normal behavior and they take a closer look.

 

[bholt]

Thanks RKA. I'm on the same sheet as you. Call and discuss 1st. I'm not familiar with all the electronics and custom systems on this saw, but know the hum and temporary vibration is not good.  :-\

 

[Birdhunter]

When I had a really bad brake squeal on a Lexus, I recorded the sound using my iPhone. It helped convince the dealer to get serious about fixing the brakes.

You might want to do a video/sound recording of your saw.

 

[Rick Christopherson]

I haven't pulled a TS75 apart in years, but I think it has a friction pad at the blade arbor. Check that for damage if the blade spun against the arbor.

 

[Gregor]

I honestly fail to imagine a way how a TS 75 could be damaged by 'nicking' a MFT/3.

With the wrong (= too deep) setting a TS 75 should saw the MFT/3 in two, no question asked, basically regardless of the blade being used, as long as you miss the steel parts of the table. The blade might get damaged (in case you do it with a really wrong one) but the saw itself should walk away smiling.

You might want to do a video/sound recording of your saw.

This. Please give us more to think about.

I haven't pulled a TS75 apart in years, but I think it has a friction pad at the blade arbor. Check that for damage if the blade spun against the arbor.

How would that make a sound while spinning up?

 

[AlexR]

Might be motor electronic speed controller, it regulates speed/power under load to give constant smooth cutting speed. Its pretty much normal for ts55 and ts75 to grumble/rumble bit while coming up to speed. Sounds almost like saws missing gear cog inside but its normal.  See if you can try out another saw in a shop or friends you'll hear if difference.

 

[sancho57]

[member=72045]bholt[/member]

Another thought would be take you saw to a brick and mortar dealer, have them fire up a saw ans how it compares with yours...
May be nothing

 

[bholt]

Great suggestions all. I'll see about the sound bite and taking to a local woodcraft store for their opinion (bought it from one a dozen years ago in another state) might be good too.