Kapex kickback

wonderbuck

Member
Joined
Mar 4, 2013
Messages
54
I'm having a lot of issues with cutoffs catching and getting thrown about both into the saw and doing damage as well as ricocheting out. Yes I am keeping the saw head down and I have a tenyru blade on there. I'm kinda getting fed up with this, any suggestions?
 
I also have this Kapex issue more frequently than I would like.  Never happened with my previous SCMS.  My suggestion: always wear eye protection!
 
Have you adjusted the depth of cut of the blade, since I did mine I have not had one kickback. You just need to adjust the depth of cut down about 2-3mm using the bolt at the RHS of the machine.
 
Ed Bray said:
Have you adjusted the depth of cut of the blade, since I did mine I have not had one kickback. You just need to adjust the depth of cut down about 2-3mm using the bolt at the RHS of the machine.

Thanks for that tip, going to try that tonight. I've been a compound miter saw user for 20 years, multiple different brands and never had a kickback until I got my Kapex. Now it seems like I'm getting them every few cuts.
 
I haven't had any kickbacks either since I adjusted mine.  The blade height was just a little too high from the factory.  The saw is a pleasure to use now.  I don't cringe at the end of cuts now.  ;)
 
BeardMan said:
This thread should be on the first/main page on the Festool FOG and Festool USA site:

http://festoolownersgroup.com/festool-tools-accessories/kapex-%27depth-of-cut%27-adjustment/

Properly adjusted Kapex can cut !!! WITHOUT !!! any kickback !

I'm wondering WHY! Festool pass it for mass selling without any adjustment!

[member=191]Rick Christopherson[/member]  Since this issue has come up a number of times lately, I wonder if it would be feasible to add instructions for this adjustment to the Kapex Supplemental Manual.

In this particular case, since the OP has stated that he has a different brand blade on his unit, the issue may not be with improper adjustment from the factory but may be due to the fact that the Tenryu blade may differ slightly in diameter from the Festool ones.  I'm just guessing--I don't have that blade to compare.

 
Since I learned to let the blade completely stop before lifting the head, I have not had a single kick back or thrown cutoff.
 
The leading cause for kickback is because the throat opening needs to be wide enough to accommodate the very broad range of miter and bevel settings of the saw. It's a tradeoff. In order to have the extra range of angles, the opening needs to be very wide.

The best solution is to add fence faces that can be withdrawn when you need to make steeper cuts, but can stay close for straight cuts.

The kickback is a rotational type, because a small offcut will be pulled backward from the blade windage, but the tip of the fence won't let the far end follow. So the piece begins to rotate into the blade, and catch even harder than just simple windage.
 
I think as [member=3891]WarnerConstCo.[/member] mentioned, we're talking about two different conditions.

I've always considered a kickback to be the pinching of the blade when cutting large/construction type materials. As you're cutting the 4x4, the internal stresses of the lumber start to be relieved and the width of the sawcut can change which sometimes results in the blade being pinched by the two sides of the lumber. This results in a violent reaction of the blade as it wants to move upward in a rapid motion. When cutting 2x/4x material I always look to see if there are any twists/warps/crookedness in the cutting area because this is a good indicator that you will probably have an issue. 

Throwing offcuts is a different matter. I had a few offcut projectiles before I adjusted the depth of my blade. The pictures below make it easy to see the issues invloved.

[attachthumb=1]

This is how I originally received my Kapex, note that some parts of the blade teeth are above the insert. This is what catches the offcut and launches it.

[attachthumb=2]

This is the blade after it was adjusted. Only a small part of the gullet is visible above the insert and this will not launch offcuts.
 

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Cheese said:
I think as [member=3891]WarnerConstCo.[/member] mentioned, we're talking about two different conditions.

I've always considered a kickback to be the pinching of the blade when cutting large/construction type materials. As you're cutting the 4x4, the internal stresses of the lumber start to be relieved and the width of the sawcut can change which sometimes results in the blade being pinched by the two sides of the lumber. This results in a violent reaction of the blade as it wants to move upward in a rapid motion. When cutting 2x/4x material I always look to see if there are any twists/warps/crookedness in the cutting area because this is a good indicator that you will probably have an issue. 

Throwing offcuts is a different matter. I had a few offcut projectiles before I adjusted the depth of my blade. The pictures below make it easy to see the issues invloved.

[attachthumb=1]

This is how I originally received my Kapex, note that some parts of the blade teeth are above the insert. This is what catches the offcut and launches it.

[attachthumb=2]

This is the blade after it was adjusted. Only a small part of the gullet is visible above the insert and this will not launch offcuts.

Cheese,

you're absolutely right!

The second picture explain it all,this is how it's supposed to be,properly adjusted blade depth.

Thanks for posting pictures.
 
Does this adjustment really keep the kapex from launching small off cuts ? This is one of main criticisms of the saw. Just asking al those who have done it.
 
glass1 said:
Does this adjustment really keep the kapex from launching small off cuts ? This is one of main criticisms of the saw. Just asking al those who have done it.

Yes, it did for me, not had an offcut come flying out since, and I don't always wait for the blade to stop either, although I try to.
 
I've adjusted the cut depth and that has seemed to taken care of the problem. Thanks for all the feedback.
 
I can fully see how the blade not been low enough will cause offcuts to get tossed about..
I don't see how the kapex can be more kickback prone than other saws though? surely it's down to user technique and maybe warped wood etc?
 
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