Domino design flaw???

[talltree]

I noticed on my first job that the fence vertical adjustment does not cinch down tightly. I backed the holding screw out and adjusted the lever to allow greater tightness. It worked fine on softwoods, but today I tried it on birch and boy did it slip, and not just once! I've had to re-attach the lever several times now.

I called Festool tech support and we talked about it. He was aware of the problem and will be sending out me a new part - #33 on the parts list.  Here, as I see it, is the problem. There are two little "feet" on part 33. They have serrations, or ridges, on the bottom which press against the fence to hold it in position. The vibration from the bit, especially in hard woods, causes the feet to slip, letting the fence move.

It seems to me that this is a serious design flaw which should be corrected. When one is cutting a row of mortises it is impossible to know when the fence is slipping without continually checking the gauge on the opposite side from the lever. I hope the new part works because this tool is a dandy and I sure would be disappointed to have to go back to dowels and bisquits.

Does anyone know of a work-around to effectively lock the fence in place?

 

[Tony M]

Oh no! not another problem. I have had mine for two weeks and haven't put it through the paces yet. Still monkeying with the Kapex :'( . Really makes my head spin!

 

[Dan Clermont]

I noticed on my first job that the fence vertical adjustment does not cinch down tightly. I backed the holding screw out and adjusted the lever to allow greater tightness. It worked fine on softwoods, but today I tried it on birch and boy did it slip, and not just once! I've had to re-attach the lever several times now.

I called Festool tech support and we talked about it. He was aware of the problem and will be sending out me a new part - #33 on the parts list.  Here, as I see it, is the problem. There are two little "feet" on part 33. They have serrations, or ridges, on the bottom which press against the fence to hold it in position. The vibration from the bit, especially in hard woods, causes the feet to slip, letting the fence move.

It seems to me that this is a serious design flaw which should be corrected. When one is cutting a row of mortises it is impossible to know when the fence is slipping without continually checking the gauge on the opposite side from the lever. I hope the new part works because this tool is a dandy and I sure would be disappointed to have to go back to dowels and bisquits.

Does anyone know of a work-around to effectively lock the fence in place?

Hi Talltree

I've cut about 500 mortises so far and haven't had mine slip. Sounds like they have ran into this issue before and hopefully the parts will resolve the problem

Dan Clermont

 

[talltree]

Tony,

I think you'll like the Domino a lot. Just a head's up. The fence vertical setting slips sometimes, especially when using the largest bit in hardwoods. After I started this thread I went back through the previous domino posts and found that others have experienced the problem. I'm hoping that there are some known work-arounds for the problem.

Do you like the Kapex? I finally settled on a little Makita 6-1/4" cutoff saw which is lightweight and very accurate, and very good for toting around.

 

[Tony M]

talltree, Kapex is an awesome saw, well thought out features. Alot bugs working in there right now, as long as the company takes care of this stuff when it goes over the 30 day thing, and hooks up the saw owners with the new updated mods it will be ok. Maybe I should have waited till next year :

 

[Les]

I've heard others talk about the fence moving. This past week I cut 100 mortises for 10x50mm dominoes. After adjusting my technique, there wasn't any slippage. I was cutting 1 1/4" cherry and the joint was w/n less than a couple thousands once I changed my technique. Will start sanding the counter-top tomorrow and I'm sure it will be flat.

 

[Hastings]

The incidents of fence slipping seemed more prevalent after the Domino was first introduced. The advice given was not to over tighten the locking lever. I have had my Domino since they first came out and use it mostly for hardwoods and have not experienced a problem with the fence moving; however, I am careful with that locking lever.

Could it be that consistent over tightening leads to excessive wear, which in turn contributes to the slippage, which leads to over tightening and so on?? Adjusting your lever to gain extra purchase may also have hurt rather than helped.

When you replace the part, you might want to be a little "ginger" with the locking lever.

Hastings

 

[Brice Burrell]

I happen to agree with Hastings. The Domino has failsafe features built into the locking mechs to prevent rockheads, some people from over tightening and damaging the tool. I've not have a problem with my fence moving.

Design flaw to one man is a good design to another, go figure.  ;D

 

[talltree]

Hastings and Brice, et al,

Thank you for your feedback. I promise to get back to you all when I have tried the new part.

As for overtightening, it certainly has been tightened a lot lately. I use the very largest tenons in my work. There is certainly a lot of stress on the fence. However, it was the factory setting that first slipped, and it slipped easily. Perhaps a mechanism which is this finicky needs to be redesigned. If they want to continue to sell Dominoes at $800 a pop, then they will look at the problem. As a woodworker I need to have confidence that I can run a row of mortises without the fence wandering.

I don't think that design engineers are intimidated when someone says "design flaw" in a public forum. These forums are a part of the everyday life of a corporation. If the issue raised has merit, then it will be attended to.

 

[Les]

As for overtightening, it certainly has been tightened a lot lately. I use the very largest tenons in my work. There is certainly a lot of stress on the fence. However, it was the factory setting that first slipped, and it slipped easily. Perhaps a mechanism which is this finicky needs to be redesigned.

Not sure why there would be a lot of stress on the fence. As I stated previously, I cut 100 mortises for 10mm dominos without the fence moving. One thing I learned while doing this was to not feed by grasping close to the cord. This works as a lever and can move the mortise.

When I first started cutting the 1 1/4" cherry countertop I started in the middle of the board. Just to check I put the first two boards together with the dominos and found I had a significant step. Probably around .010". Also had a the tool catch when retracting in from the mortise on 3 mortises. I had held the domino by the back and had feed as I had normally done with the 5mm mortises. Stepped back and thought now what am I doing wrong? Not what is wrong with tool. I had gotten flush joins before.

I placed the domino against the piece and started checking to see if the tool would rock when I held it at the cord end. It did. Moved my hand up to the two finger notches behind the switch and wasn't able to get any rock with out forcing.

Next, why did the tool catch? Simple enough I was retracting the tool as soon as it bottomed out. Started letting the chips clear for a second when at full depth and no more catching.

Bottom line is shown below.

First pic shows step on first 2 pieces joined.

Second shows no steps on the rest of the joints after changing technique.

Third shows 10 mortises per board, 10 boards total.

Pictures of the top are before sanding. This was how flat and flush it was out of the clamps.

As far as a design flaw, I guess I wouldn't agree that it's a design flaw since not many people are having the same problem. I realize you have a real problem but hopefully it will be solved with a non-flawed locking lever.

 

[Dave Ronyak]

I had a problem with varying height of the mortises the second time I used my Domino.  The problem was due to my poor technique and not the
Domino machine.  Mine was one of the first units put into consumers' hands.  I have made ~500 mortises without any problems, the most recent being addition of a mitred perimeter edge of 5/4 stock around a 3/4" plywood center panel.  Each piece of edging had multiple domino mortises along its length and 2 mortises side-by-side at each mitre.  My keys to success with my Domino machine have been to carefully adjust the fence and snug its clamp lever (don't overtighten it), placement of one of my hands on the grip handle on top of the fence, and placement of my other hand on the thin part of the motor housing and carefully pushing the unit straight in while firmly holding the unit in position with the hand on the top handle on the fence.  Festool's factory trainer recommends gripping the motor housing very near the cord end and simply pushing it it to cut the mortise.  This hand position arguably helps to reduce any tendency to push the motor off axis.  You also need to be careful regarding what surface you are referencing from.  Festool generally recommends referencing off the top surface of your stock and the bottom surface of the Domino fence.  If there is a fault in your particular Domino unit, I am confident that Festool will resolve it to your satisfaction.

Dave R.

 

[Les]

Dave,

Whatever works best for the individual. ;D We will agree to disagree on where to hold when feeding. ;D

 

[Dave Ronyak]

Les,

We completely agree on using whatever works for oneself.  I should have explained that the hand I use to plunge the Domino machine is not even gripping the barrel housing of the motor.  I try to simply push it axially along the plunge guide rods built into the Domino while firmly holding the unit in position with my other hand on the top handle (the one on the fence).  I should also have stated that for that mitred edging, I elongated the mortises nearest the mitre to enable rotating the edging into position relative to the center plywood panel. 

Dave R.

 

[talltree]

Dave and Les,

What great feedback! I truly appreciate it and will put it to use on my current and my next projects.

As for work style, I suppose I have a combination of careful and not-so-careful technique. I usually try to balance a tool correctly, such as random orbital sanders or drills, but didn't think for a moment that the way I held the Domino could cause the fence to slip. This is a good forum.

I noticed that the wear was uneven on the part which Festool is replacing. It could have been a bad casting. I'll keep in touch.

 

[talltree]

OK, I installed the new part and have begun the testing. I find that adjusting the angle of the fence/table to 90 degrees and placing it on top of the board gives greater accuracy in drilling the tenons.

The adjusting lever is loose when turned counter clockwise, and is pretty snug when tightened. I don't see how it can be overtightened actually, since it can only be turned about 180 degrees in the tightening process. But I have to repeat that the fence always moves no matter whether I tighten it "mildly", "snugly", or "very snugly".

I drilled nine mortises on a poplar 5/4 S4S board. I repeated this process four times. I held the domino near the end of the barrel with the cord laying loose against the last two fingers of my hand. I held it firmly but gently so that I did not place pressure inappropriately. The only pressure I placed was with my other hand which was pressing down on the fence/table to hold it firmly against the top of the board. In each case I drilled slowly and patiently. In each case the fence moved a little bit by the time I had reached the end of the board. Four times.

Here is an interesting observation. If I tighten only mildly, when I press up on the bottom of the fence/table, the fence/table moves up fairly easily. If I tighten snugly, it no longer moves easily, but moves up with firm pressure. If I tighten very snuggly, it will move up with very firm pressure. At this point I degreased all the sliding parts with lacquer thinner.

With this in mind I set the knob on "very snug" and mortised 4 rows. This time the fence/table did not move. 

I have some conclusions.
  1)  The mechanical action of "snugging" works better the tighter you snug it.
  2)  The fence/table moves because the contact surfaces are very smooth and slick. It it were me I would address this issue so that there is no chance of movement whatsoever once the lever is tightened.
  3)  The tool may have left the factory with a slight coat of oil on the contact surfaces.

Poplar is a moderately soft wood. I will get back to you when I use a harder wood.

What do you think?
Will

 

[Les]

Hey Will,

Sounds like you found a possible problem and solution at  the same time.

I just joined some oak 3/4 x 5 1/2 for some slab doors. I was using the 5mm tool and got terrrible results. Thought I had done things correctly but as they say "after further review" I saw one of problems and deceided I also had a problem with the feed rate.

I cut the mortise using the pin and the rest of the mortises using the out riggers set to 100mm. I didn't have the outrigger tight on one side. The clamp was bottomed out without tightening. This caused one board to be ok and the other was weird. Both the spacing and height were off. The other problem was I was feeding too quickly into the stock at the start of  the cut. I slowed way down on the entry and then got mortises the same height from the face within < .oo5.

Seems the smaller 5mm tool has more flex causing the bit to wander upon entery into the stock. I didn't have to be as careful when using the 10mm bit.

The domino is a very accurate but somewhat touchy tool. Everything is right then the tool makes great mortises.

I don't have to tighten my fence any more than snug to keep it from moving. If you continue to have a problem with it moving, call Festool service and they will fix it. Hard to give it up, but you'll be glad you did if you can't fix it yourself.

 

[Mike Goetzke]

I noticed on my first job that the fence vertical adjustment does not cinch down tightly. I backed the holding screw out and adjusted the lever to allow greater tightness. It worked fine on softwoods, but today I tried it on birch and boy did it slip, and not just once! I've had to re-attach the lever several times now.

I called Festool tech support and we talked about it. He was aware of the problem and will be sending out me a new part - #33 on the parts list.  Here, as I see it, is the problem. There are two little "feet" on part 33. They have serrations, or ridges, on the bottom which press against the fence to hold it in position. The vibration from the bit, especially in hard woods, causes the feet to slip, letting the fence move.

It seems to me that this is a serious design flaw which should be corrected. When one is cutting a row of mortises it is impossible to know when the fence is slipping without continually checking the gauge on the opposite side from the lever. I hope the new part works because this tool is a dandy and I sure would be disappointed to have to go back to dowels and bisquits.

Does anyone know of a work-around to effectively lock the fence in place?

TallTree - I played around with my new Domino jointer a few days ago. I tightened the fence lever with about as much force that I applied to my previous P-C plate jointer. I machined 10 mortises (5 in each) in my test pieces. The fit was terrible. I measured the distance from the reference surface to the top of the slot and the distance became progresively larger. The last was 0.040" off from the first. I torqued it pretty good the next test and only got a few thousands variance between measurements. I saw on another board that the problem is related to the surface the the two-footed clamp goes against is too smooth and that newer Dominos will have a rougher surface area for the clamp foot to mate against.

 

[talltree]

Mike,

This sounds a little simplistic but the one thing I did that seemed to solve the problem was this: I separated the fence from the body and used lacquer thinner to clean the contact surfaces of both parts. To separate, take off the little plastic caps on top of the fence (it's easy - just tap them gently with a hammer and they slide out) I can't remember if I removed the pressure foot first.

I think there was a light coat of oil on the surfaces. I just used it for 90 mortises in poplar using the largest tenons and it didn't budge. I snug the pressure foot down pretty tight.

When this tool is firing on all cylinders it is an awesome device. As Les said, the tool is a bit finicky.

 

[Brice Burrell]

Another option is to scuff up the mating surfaces with sandpaper for a bit more friction.

 

[gkeas]

The first few times I used my Domino, I had issues with the alignment of the joints.  I was concerned that I needed to send it back, but I let it ride, pending further info.

Subsequently, I read a post about the feed rate for plunging the joiner in different materials, and realized that I was going WAY TOO SLOW, in all instances.  I've since increased my plunge speed, and my joints are now FLAWLESS.  Every one has  been perfect since reading this post.  I can look it up if anyone wants me too.

Also, 3/4" stock is too narrow to reference the fence if you're joining from the work surface.  20mm is minimum, so raise the stock if necessary.  (this was another goof I made a few times).

Hope this helps.