Broken domino bits, I'm getting frustrated

[aff]

The same thing happened to me. Both the 5mm and 6mm bits broke while using the domino on maple. I was not pushing hard on the tool and I was using it with a strong Fein vac. I called the 800 number on the tool and basically I was dismissed as pushing the tool too hard, thanks for your call!

I will try the the CMT bits, if they too break, this will be a serious blow to the domino. There is no rival to the domino right now but I can do most what it does, albeit slower, with a router jig.

Festool should make a stronger bit, they can and should.

 

[Administrator_JSVN]

I looked at your photo again. I know you said that you didn't hit anything metallic, but it sure looks like some scoring around the bit.

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[festnoob]

I looked at your photo again. I know you said that you didn't hit anything metallic, but it sure looks like some scoring around the bit.

[attachimg=#]

That looks crazy...I've been using the same 5mm through several projects and never had that happen. Looks stripped!

 

[John Bates]

Once the bit has broken, obviously it will make contact with the broken piece. Of course there will be scoring, mine did the same. If the plunge rate was too fast, it's a learning curve, whether it's costly or not.

 

[Brice Burrell]

Shane, I suppose it's possible the scoring could be from hitting the broken off piece as the plunge continued.  Ha, John beat me me to it.

 

[PeterK]

Well if this bamboo is some type of layered compressed stuff and from China, I wouldn't be surprised at all that there may be "foreign" objects used as filler. Have found the most amazing crap used as filler in Chinese plywood.

Sure looks like the bit hit some hardened metal to cause that type of gouging scoring of the bit. Never seen that before.

I have broken 2 5mm bits used in plywood. Both times it was the carbide tip snapping off but no other visible damage. I believe in my case it was the changing density of the material while plunging as I could easily feel the cutter grabbing at times. Had great success in normal hardwoods of constant density.

 

[iamnothim]

Sorry but I'm having a hard time believing that Bamboo did this damage.
Also.  The score lines are evenly spaced and perpendicular to the bit and they get proportionally deeper as they reach the end of the bit.

 

[iamnothim]

Here's a blowup of both images set side by side with the contrast enhanced.
I'm just say'n ....  But...they don't look like the same bit-tips to me.

 

[grbmds]

Does it sound like metal against metal when in use? Those look like they are made by something metal rubbing against the bit, like against some part of the Domino. Again I ask if you have talked with Festool service. I would do that and send them the picture.

 

[jacko9]

I have had some pretty bad plywood coming in from China with overlaps and lots of lose filler.  I would take a close look at the bamboo for foreign objects embedded.

Jack

 

[grbmds]

Have you worked with bamboo before? If so, what does it do to other cutting tools like saw blades, other router bits, etc.? Have you tried the a new bit on another type of wood repetitively to see if the same problem exists? I definitely would consult Festool Service. Even though my experience with Festools has not been a perfect situation, I have not found a true quality problem. I'd find it hard to believe it was the bits. I have not used my Domino that much but have cut a 1/2 dozen or so test cuts in preparation for some drawers I'm going to make. The bit didn't show any wear at all.

 

[Stephen B]

I have had some pretty bad plywood coming in from China with overlaps and lots of lose filler.  I would take a close look at the bamboo for foreign objects embedded.

Jack

[size=11pt]
Yes, my money is still on the quality and abrasiveness of bamboo based product.

I also agree with Shane regarding hard woods. The majority of my domino experience to date has been with projects using Australian Mountain Ash, which is very hard and strong. Most was naturally cured and/or recycled. To give you an idea, new plantation Kiln dryed Ash is usually rated at minimum of F17. I have also used my domino in RedGum which is tougher still.

Edit.  Who actually makes the Festool Domino Bitts, is it CMT?

 

[NYC Tiny Shop]

My  [2cents] [2cents]

Bamboo is very hard. I would be afraid of breaking a bit, also. I would be plunging extremely slow while probably pulling back repeatedly to prevent heating up the bit.  These bits are not diamond cutters. They are somewhat fragile and need to be treated with care. That said, I'm surprised with how well mine have held up this past year.
BTW, those CMT bits look pretty good.  I didn't see 12mm or 14mm ones.

 

[endgrain]

The scoring on the bits is from the cutter rubbing on the broken tip after it broke off (I kept plunging trying to finish the mortise). I am sure there was no scoring on it prior to me using it that day since I checked the bit before the day's first plunge.

After doing some more reading on the bit, it looks like it's not a solid carbide bit as I assumed and only the tip is carbide. I've stacked the body portion to the broken tip and to me it looks like it's breaking right where the carbide bit joins the body.

[attachthumb=1]

The bamboo too is very fibrous and the glue in between the layers and the knots, maybe the bit is catching on one of them and getting twisted off.

[attachthumb=2]

Thanks for all the quick replies too. On the bright side, I'm glad the broken bit didn't end up on my eye (or eye protection)  [unsure]. On a related note, my 5mm CMT bit arrived today but I don't know it will do any better. I can see a line where the carbide portion joins the body.

[attachthumb=3]

The only consolation, if it breaks, is I'm only out 21 bucks instead of 33, but for now, I'm done with my bamboo project (I finished it off with the 4mm bits).

 

[jtwood]

I saw a chart, I believe on here someplace, that had a recommendation for how long to take to plunge when cutting for the domino.  Basically, what I took from it, is 1 (one) second per bit size.  In other words, for a 5mm bit, take 5 seconds to make the full plunge.  For an 8mm bit, take 8 seconds, etc.

I've made plunges that way in hard maple without problem, but not in anything as hard as bamboo.

One other thing occurs to me:  most bamboo products are laminated.  I wonder if the glue used in some of them could cause a problem?

Steve

 

[John Bates]

CMT's part number for 14mm is 380.141.11.

 

[iamnothim]

The scoring on the bits is from the cutter rubbing on the broken tip after it broke off (I kept plunging trying to finish the mortise). I am sure there was no scoring on it prior to me using it that day since I checked the bit before the day's first plunge.

After doing some more reading on the bit, it looks like it's not a solid carbide bit as I assumed and only the tip is carbide. I've stacked the body portion to the broken tip and to me it looks like it's breaking right where the carbide bit joins the body.

[attachthumb=1]

The bamboo too is very fibrous and the glue in between the layers and the knots, maybe the bit is catching on one of them and getting twisted off.

[attachthumb=2]

Thanks for all the quick replies too. On the bright side, I'm glad the broken bit didn't end up on my eye (or eye protection)  [unsure]. On a related note, my 5mm CMT bit arrived today but I don't know it will do any better. I can see a line where the carbide portion joins the body.

[attachthumb=3]

The only consolation, if it breaks, is I'm only out 21 bucks instead of 33, but for now, I'm done with my bamboo project (I finished it off with the 4mm bits).

Excellent photos.  If the carbide tip broke at the weld, I think you have a case for a defective bit.

 

[kenkrawford]

I don't mean to hijack this thread but I was browsing the boards and happened to see this post.  
I just bought a Domino 500 2 days ago and had just finished cutting 15 mortises (not all at the same time) when my bit broke.  The material I was working on was spruce so I think that probably discredits the "bamboo too hard" theory.  Note that my bit also is scored on the shaft.  I believe this is due to the tip being trapped in the mortise and contacting the shaft.
I'm going to call Festool tomorrow and see what they say.  Needless to say I'm a bit disappointed with my new tool.

 

[jacko9]

Ken,

Keep us posted as you find a solution to the broken bits.

Jack

 

[mattdh]

to me- they all look like they are breaking off in about the same place. any chance of a bad batch? is it just 5mm bits having this problem?