Broken domino bits, I'm getting frustrated

I must have jixed myself posing on this thread.  Broke 2 5mm bits today. Was using oak. One of the tips twisted off no scoring or nothing. I will post a pic of it tomorrow.
 
mattdh said:
I must have jixed myself posing on this thread.  Broke 2 5mm bits today. Was using oak. One of the tips twisted off no scoring or nothing. I will post a pic of it tomorrow.

Hate to say it. It is either bad technique or REALLY bad parts. I have had my 700 XL for over 6 months and never came close to snapping a bit with my Seneca adapter.

I hope you figure it out, but in the meantime, slow the plunge down!!

Cheers. Bryan.
 
i just had this happened to me last night, after like countless mortises.

Just some 3/4 oak ply.. plunging was slow and steady and then the last plunge gives that weird sound, and then after some examining, i was shocked to see a piece of metal lodged inside the mortise.

So call festool support? or you think lee valley will just replace it on the spot, 'cause i'm right in the middle of a project.
 
The 5mm bit mystery has yet surfaced...

I have also broken off two 5mm bits over the years, never another sized bit.
By the time I broke them off I was already a "skilled" plunger with hundreds of holes under my belt.

If it was another size bit I would be thinking, bad luck/operator error but I do keep a spare 5mm bit in the kit. ;)
 
I had SOMEHOW (likely user error) messed up the gears in my Domino 500, and that was the cause of my three broken 5mm bits. The larger bits were ok, but the cutting was obviously rough. I went through the whole deal of trying different feeding speeds, being sure I had the machine held correctly, always had a dust extractor on, and so on... On the advice of a nice gentleman on the Festool Roadshow truck, I sent it in for inspection. It came back repaired and cutting smoothly - no charge, even though it was significantly out of warranty...
Pg 8 of the supplemental manual: "Rotate the (mortice width) dial ONLY when the motor is running." To me, that is counter-intuitive (and I believe the opposite is true for the Domino 700) - so I'm pretty sure I did that, not having noticed the prohibition. It might be worth sending the Domino 500 in for a checkup. Mine now works, I think, better than new. I found it frustrating to use early-on, and probably damaged the gears in there pretty early. After repair, it's the tool I expected it to be.
 
If it is not a manufacturing defect, then the likely cause of breaking the bit is user error: do not move or retract the DJ UNTIL the motor has come to a complete stop. If the rotating/oscillating bit touches the mortise wall (likely the top) as you withdraw the tool, it could break. This isn't as much a problem with the larger bit.

You can withdraw the tool without waiting for the motor to stop IF you are sure you can do it without tilting the tool downwards or upwards (it poses a risk even if it is tilted lightly)

Yes, it is inconvenient but it will stop the small bit from breaking. Wood hardness should not be a concern as I have used the small bit on hard maple, tigerwood, oak and whatnot with no breakage issues.

Chuck
 
I'm down 3 more 5mm bits since the last time i posted about this. its the only size i have broke. i totally chalk it up to bad technique- when i throw on the 5mm bit i just get so excited i just start jamming it in to everything i can with out a care in the world. i dont care how slow and steady you think I'm not going- i have solved my problem- i use every  size but 5mm
 
My $.02 is that it is important to hold the domino in close contact to the wood into which the domino mortice is being drilled. This means holding the domino perfectly still. -- That means that I focus 90% of my attention in that area.  It is sooo easy to tip or tilt the domino at the beginning and end of my domino drilling  operation, which can put a lot of pressure on the tip of the domino cutter.

Hope this will help,

Joe
 
Here's a thought...when I first started using the Domino, I found that if I didn't concentrate, I would kinda lift the back end of the tool while plunging and I could hear it in the motor.  Also, if I'm not careful, I tend to jerk-plunge, rather than slow and smooth plunge.  That said, bamboo is hard and abrasive and seems it would require and very slow and smooth plunge.
 
Some great advice here. The slow, level and well seated plunge cut is certainly what the LV folks insist upon at their seminars. That said, the images do show voids in the bits so there may indeed be a bad lot out there. In the interest of productivity, I will order some replacement bits when my director of finance (my wife) approves Project Domino.  ;)

The discussion of the type of wood reminded me that bamboo is very high in silica, especially in the outer layers. Indeed, if you have a drum sander and a thickness planer, it is recommended that you use the drum sander for adjusting the thickness, as it will quickly dull the cutters on a thickness planer.

 
The domino certainly has its share of learning curves and there has been some great advice here.  But breaking router bits, drill bits, domino bits is part of the woodworking world and usage experience.  Logically larger bits can withstand more lateral pressure. 

Peter
 
I've gone through several 5mm Domino bits in around 5 years of owning the tool. Mine gets used almost daily, mainly for cabinet boxes in veneer core ply. For the most part I've been satisfied with the lifespan of the bits, obviously they simply dull after awhile. About 2 years ago I'd say there seemed to be a bad batch, I recall breaking 2 in a week and 4 total within a month or so. I don't doubt that another bad batch could be out there.
By the way I tried a CMT brand one during that phase and it was terrible. Seemed dull to start with and broke within a couple weeks. I would never buy another.
 
I've made hundreds and hundreds and hundreds of little adjustable French cleats out of baltic ply with the tiniest, most fragile bit of the bunch in a 700 using the Seneca adaptor and I have never had a single one break on me. I honestly don't see how the dense, fibrous material could *not* have something to do with the less-than-satisfactory experiences reported here.
 

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