Catastophic Failure - Festool Kapex 120

[Rockne]

I was using my Kapex 120 EB today.  I went to make a basic cut on a 1/2" x 4" piece of oak when both of the following happened (I'm not sure in which order): the clear plastic blade guard cracked in several places and the saw "kicked" and did not come anywhere near completing the cut.

At first, I thought that it might have been some sort of user error, but the wood was still being held down by the hold down (singular) and was flat against both the table and the fence.  There was nothing wrong with the workpiece either. 

My revised hypothesis is that the blade guard itself failed - released quickly and activated a stop in the machine which explains why the cut was barely just begun. 

Has anyone had this happen before?  Has anyone replaced a cracked blade guard?  If my hypothesis is correct, this seems like a pretty major issue that Festool needs to resolve promptly with a recall and replacement of the blade guards. 

Edit to add: This was the first cut of the day - There were not prior cuts where a piece of wood may have gotten caught in the mechanism.  The cut did not eve make it through the depth of the wood - so only about 1/4" of the top half of the wood was cut. 

 

[squall_line]

A recall would only be indicated if this was happening to a number of users regularly.  This is the first time I've read of this particular failure mode myself.

How old is the saw?  How has it been stored?  Any loose nuts or bolts on the floor from the guard letting go?

 

[Mortiser]

I note you said, "...still being held down by the hold downs." Did you have your work clamped on both sides of the saw blade?
If so, that likely caused your kickback. You never want to clamp the wood on both sides of the blade. Many boards have tension in them from built-in twisting or warping and you release that tension when you start your cut. The relieved tension in the wood has to have somewhere to escape. If locked down on both sides of the kerf, the wood can bind against the blade and will cause a kickback. You'll want to replace the guard and hopefully there is no other damage to the saw.
Sorry you had the problem. Hopefully you can get your Kapex up and running again soon and not experience any other issues. The Kapex is a great saw, just be careful to use proper and safe techniques.
Good luck!

 

[Rockne]

I note you said, "...still being held down by the hold downs." Did you have your work clamped on both sides of the saw blade?
If so, that likely caused your kickback. You never want to clamp the wood on both sides of the blade. Many boards have tension in them from built-in twisting or warping and you release that tension when you start your cut. The relieved tension in the wood has to have somewhere to escape. If locked down on both sides of the kerf, the wood can bind against the blade and will cause a kickback. You'll want to replace the guard and hopefully there is no other damage to the saw.
Sorry you had the problem. Hopefully you can get your Kapex up and running again soon and not experience any other issues. The Kapex is a great saw, just be careful to use proper and safe techniques.
Good luck!

No, that's just a typo.  It was being held down on just one side.  Also, the cut didn't make it even a full 1/2 way through the board (it basically cut a little more than a nick in the board, which is why my first reaction was that there was something in the board), so relieved tension could not be an issue because it never even got that far.

 

[Rockne]

A recall would only be indicated if this was happening to a number of users regularly.  This is the first time I've read of this particular failure mode myself.

How old is the saw?  How has it been stored?  Any loose nuts or bolts on the floor from the guard letting go?

Purchased in Feb 2015.  Saw has run mostly flawlessly (I say "mostly" because I don't remember any issues, but couldn't swear that there hasn't ever been one - unlike my Domino).  Nothing loose.  The saw has never left it's original place (i.e. it's not a work saw - my guess is that many people have used their saws more in a single week than I have during the entire life of my saw).

It really looks like the clear plastic failed.  This may be subject to bias on my part, because I've always thought that the plastic was suspect (It's like the dust collector adapter for the OF1400 . . . it seems extremely brittle and I have broken at least two of those). 

 

[ChuckM]

Not sure if this helps in anyway:
https://www.festoolownersgroup.com/...ing-cut/?PHPSESSID=3qd76d86iv0sc350v61d4hnur4

 

[Rockne]

Not sure if this helps in anyway:
https://www.festoolownersgroup.com/...ing-cut/?PHPSESSID=3qd76d86iv0sc350v61d4hnur4

Thank you, but the part that broke on my saw is the large clear plastic guard - the part that rotates/retracts as you activate/lower the saw blade.

 

[jeh]

I was using my Kapex 120 EB today.  I went to make a basic cut on a 1/2" x 4" piece of oak when both of the following happened (I'm not sure in which order): the clear plastic blade guard cracked in several places and the saw "kicked" and did not come anywhere near completing the cut.

At first, I thought that it might have been some sort of user error, but the wood was still being held down by the hold down (singular) and was flat against both the table and the fence.  There was nothing wrong with the workpiece either. 

My revised hypothesis is that the blade guard itself failed - released quickly and activated a stop in the machine which explains why the cut was barely just begun. 

Has anyone had this happen before?  Has anyone replaced a cracked blade guard?  If my hypothesis is correct, this seems like a pretty major issue that Festool needs to resolve promptly with a recall and replacement of the blade guards. 

Edit to add: This was the first cut of the day - There were not prior cuts where a piece of wood may have gotten caught in the mechanism.  The cut did not eve make it through the depth of the wood - so only about 1/4" of the top half of the wood was cut.

I have had my first one since 2011 I think (whenever they were first sold in the US). No problems other the burnout a good majority of them suffer from. I replaced the part and was back in the game immediately. You just had a case of bad luck.

 

[Birdhunter]

Is there a possibility that the blade guard got pushed against the blade during or before the cut?

 

[peter halle]

I might suggest that you contact Festool directly about your issue.

Peter

 

[harry_]

As someone that has actually removed the blade guard before, I can assure you that there is nothing there to shut down the saw upon its failure.

There are only a few thing that will stop a Kapex:
Release of the trigger
Thermal overload
or an outright failure of some other internal component.

Since you are out of warranty, the cheapest fix is to call festool ad order a new guard and replace it yourself. All you have to do is pull the blade and remove the 3 screws on the arbor shaft cover. Be careful as there is a sliver of spring steel in there acting as a bushing for the guard. You can take a look at EKAT for the exploded diagram. Also the guard return spring can be a bit of a bugger. but all in all it is a relatively easy DIY repair.

I would remove the blade and make sure the saw otherwise functions normally and go from there.

 

[mino]

...
Release of the trigger
...

This.

When I shredded the blade guard on my Makita chopsaw (LS1040), the saw stopped very fast indeed - the shock from the noise meant I reflexively released the trigger, the motor break kicked-off and the blade stopped still stuck "inside" what was left of the blade guard.

Turned out - in my case - the blade guard came loose, "interacted" with the blade, which in turn made mincemeat out of it. It was in like 20 pieces all over the shop, biggest piece still stuck under the saw. Only a small 3" part was still connected with the guard pivot ...

Thankfuly no flying piece of plastic hit me in the eye. That is when I learned to wear glasses even working with "blade-protected" tools ... eh.

Nothing against Makita, it was a pure operator error - I have apparently not secured the guard "fixing" nut after a blade change the day earlier.

After that, I tested a bit, and with te LS1040 the same can happen when a major side-force is inadvertently applied to the guard - it can force the guard to come in contact with the blade and bad things happen then.

Point being, AFTER an incident like this the shock will make people forget what they did immediately before #&@# hit that fan. The reason I reliably know the cause is the screw securing the guard on my saw was very very loose. I completely missed the guard "falling" into the blade during the cut - it happened too fast.

Had I somehow pushed the guard into the blade instead, I would probably not remember that happening ..

I would advise to review the mechanism, screws, etc. and try to see what might have caused -or allowed- the blade to contact with the guard. This includes testing how much side-force you would need to apply to make that happen on your saw. Not have a Kapex, but I was surprised how little was needed with my Makita. I my case I found that a hand moving around and hitting the guard would do the trick ..

 

[Birdhunter]

I had the plastic blade guard on my SawStop essentially explode. My fault. The guard has two pieces that articulate. I apparently let the left side plastic contact the blade when I lowered the guard down to the wood. When I hit the start button, plastic pieces went everywhere. I always put on my safety glasses when I walk into the shop. One of the pieces cut my arm and one hit my cheek.

Now, I check the guard every time I lower it. One explosion is enough!

 

[mino]

Thinking about this more, I would say the KAPEX guard is WAY BETTER than the one on my Makita /and most other saws/ which are transparent.

To be transparent, a non-reinforced polycarbonate is used - which is fragile in turn. On the LS1040 the interaction with the blade shattered the guard into tens of sharp pieces which were sent flying around the shop. So in my case the blade clearly won the encounter.  Better than pieces of blade flying, but not by much ... My saw worked - unlike yours - but because it no longer had a guard attached. Eh.

The KAPEX guard is from a non-transparent material which would be way tougher. That it "only" fractured on contact with the blade is a testament. Would say it did its job here in stopping the blade while staying mostly in-place.

 

[Rockne]

I would advise to review the mechanism, screws, etc. and try to see what might have caused -or allowed- the blade to contact with the guard. This includes testing how much side-force you would need to apply to make that happen on your saw.

So far as I can tell, there was no contact between the clear blade guard and the blade itself.  The blade guard is still in one piece (though it is cracked, it is still in one piece).  The cracking has caused it to need to be "squeezed" in order to be rotated inside the body of the saw (which was not the case when I began my cut). 

 

[Rockne]

Is there a possibility that the blade guard got pushed against the blade during or before the cut?

If that's the case there is no evidence of that happening - no evidence of the blade ever touching the guard.

 

[squall_line]

I would ask for pictures to help assess what may have happened, but if you are truly concerned that there is an issue with the unit, it would be best to contact Festool USA directly and talk to them about options to inspect and repair it, as Peter suggested.

 

[Rockhigh]

Hello All,

Something very similar happened to me on my 2021 REB, I started the saw and it came up to speed and went to make started to lower it to make a cut and boom. The plastic shroud broke apart and spring went flying. Nothing was stuck in blade. Blade did not even com in contact with the wood ?
[attachimg=2]

 

[squall_line]

Hello All,

Something very similar happened to me on my 2021 REB, I started the saw and it came up to speed and went to make started to lower it to make a cut and boom. The plastic shroud broke apart and spring went flying. Nothing was stuck in blade. Blade did not even com in contact with the wood ?
[attachimg=2]

With it being a 2021 model, have you contacted Festool about warranty coverage?

 

[Rockhigh]

I sent it in to Festool and still waiting for it to be repaired, I just would like to know what happened. It kinda startled me lol.

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