Mafell/Triton 'Duo Dowell' versus Festool Domino

[monster]

I think some people are misunderstanding the 'sloppy setting' on the Domino cutter.

The sloppy setting is only available in one plane - ie over the width of the domino, so there is never any slop in the fit regarding the thickness of the domino.

In practice it is often only necessary for one domino to be sited perfectly accurately in both its x and y axis, this will accurately locate the two pieces of material being joined. The subsequent dominos can then be quickly and easily sited via registering off the side of the workpiece using the fence on the domino cutter this will give an accurate location for the position of the domino in the thickness plane but in the width plane the 'sloppy setting' can be used so that there is no need to highly accurately find the position of the slot along this axis as the first accurately placed domino has already ensured accuracy in this axis.

Once the user accepts that there is no need to have every single domino fitted on the 'tight setting' and the integrity of the joints is not compromised by using the 'sloppy setting' - which remember is only sloppy regarding the width of the domino, the domino still being a tight fit on its thickness, you will then realise how brilliant this concept is as one of its beauties lies in the speed of operation that not having to accurately lay out each mortice brings.

 

[petermillard]

For context, I’ve had the Domino 500 since it was available, I own the Lamello Zeta P2, I’ve used the Mafell Duo-Doweller (3 month extended demo) and I’ve had (briefly) three of the Triton dowellers.

I did a video on the Festool/ Mafell/Lamello here. Long story short, the Domino is the most flexible / versatile of the hand-held jointing systems, as well as being the least costly (at the time).

I found the Mafell really hard to use - call me a weedy weakling, the plunge takes a crazy amount of effort - but it’s the best made of the three, and the rack & pinion fence is a delight. But as I found in my Loose tenon Basics video each face of a 5x30 domino has as much gluing area as a 6x30 dowel; dowels are cheap and plentiful but demand precision, whereas dominos don’t cost much more than two similarly sized dowels, but the Domino is a precision tool (Roy’s DF700 notwithstanding) that lets you work loosely.

I think Festool missed a trick by not letting the user switch off the Domino waggle - a Domino-shaped single-doweller that also worked for loose tenons would be an interesting confection - but perhaps that’s planned for a future revision.

As for the Triton, I had this scheduled to feature in my ‘Festool vs Cheap Tool’ series way back, but I bought three of them (and returned them all) without getting one that worked adequately, and FFX basically refused to sell me another.

I’m told that Triton have discreetly re-engineered their doweller and they’re better than they were, but I’m disinclined to try another, especially when a simple loose tenon jig has so much more flexibility.

HTH P

 

[MikeJhn]

I assume he is cutting dowel holes so he can attach a vertical panel.

So do I, but the motor is not inline with the fence or the work piece, can't work out where the drill face is, unless there is a bevel gear connection between the motor and the drill shank.

 

[petermillard]

Can someone explain what this chap is doing?

He’s getting the Triton branding visible in a staged PR photo. Edited to add that clearly neither the model nor the art director have a clue about how the tool works, or they do but don’t care. Brand is all…

 

[MikeJhn]

Never having used a Triton due-dowel or even seen one I was beginning to doubt myself.

 

[sometimewoodworker]

I think festool have got it all wrong with their sloppy settings on the domino. I might like say 0.5 to 1mm of slop to allow for any alignment but 6mm or 10mm is just ridiculous. my approach if needed is to just pare a sliver of each edge of teh domino. If I wanted more adjustment then use the biscuit jointer

I strongly disagree, the exact fit domino slots are only needed on one side of a joint and then one of the other side, to allow exact alignment. In my opinion, and others tests, using exact fit slots makes very little difference to the strength of the joint. In point of fact when I make wider dominoes, for the wide wiggle setting, I leave the ends with just the sharp corners trimmed at 45 degrees, this is because, if you actually do the calculations the rounded ends are a small percentage of the glue area of the domino.

 

[Spectric]

I have looked at those Triton machines and discounted them fairly quickly, based on a really cheap biscuit jointer and although at first glance they look like a solution there is sufficient movement in certain parts that is not conclusive to precision. Dowels need very tight tolerances because even a slight error can sum to something way off, just look at one of those asian knockoffs of the dowelmax which looks identical but there is a slight non symmetry in the drill block so alignment of the opposing workpieces means that joints either don't close or require excess clamping force.

The word not yet mentioned in these discussions is void, with a dowel it is a tight fit all round, with a sloppy domino albeit in just one plane you will end up with voids, if you introduce deliberate sloppyness to achieve alignment you must also be introducing weakness, whether this effects the final joint in it's given application is another question.

If we compare 8, 10, 12 and 14 mm domino's all at 100 mm length the glue area on the flat sides are all equal, just spaced further apart. The difference in glue area is that given by the radiused ends, the 8mm gives 2500mm^2 and a 14mm gives 4400mm^2 so once the slot is wider this surface area is no longer in contact for gluing and all these domino's are held in place by the same glue area.

The major contribution to shear strength is the actual volume of the domino, so a 14mm will have much more strength than an 8mm domino but in the sloppy mode both retained by the same area of glue, with a void in which to potentially move if the glue fails.

The actual joint strength has to be a balance of material removed to fit the domino versus amount of material left so just fitting the largest domino could result in a weaker joint, but an interesting question is what has the best shear strength, a single domino or four dowels? Any advanced users of Matlab out there could potentially model this!

 

[Hornbeam]

I strongly disagree, the exact fit domino slots are only needed on one side of a joint and then one of the other side, to allow exact alignment. In my opinion, and others tests, using exact fit slots makes very little difference to the strength of the joint. In point of fact when I make wider dominoes, for the wide wiggle setting, I leave the ends with just the sharp corners trimmed at 45 degrees, this is because, if you actually do the calculations the rounded ends are a small percentage of the glue area of the domino.

I think it depends upon the type of joint you are doing
A tight fitting joint or at least tight with a gap filling glue means that you are getting both the strength of teh glue and the shear strength of the domino
If edge jointing boards, there is very little shear and so slop is Ok and allows side to side adjustment
If I was replacing a slightly wider mortice and tenon and using 2 dominoes say in a cabinet door I would prefer both to be tightish fit. As said in a previous post do use the sloppy settings but then use a custom domino o2 split to make a wider overall loose tennon

 

[HOJ]

@Spectric I can see the Engineer coming out, personally I can't recall ever using the "sloppy" settings on any thing I've made using domino's from the 4mm to purpose made ginormous ones.

Any way I'm much happier using this to make proper holes!

 

[Spectric]

That looks like a chain morticer, you must be working with some large timbers such as green oak frames. Yes I just like precision and tight joints without voids or sloppy settings. Maybe had I come straight to the domino without the background in dowels then things would be different but if this had been a marriage then that festool 700 would have been divorced by now and not just keeping my lawnmower company.

 

[Hornbeam]

I have looked at those Triton machines and discounted them fairly quickly, based on a really cheap biscuit jointer and although at first glance they look like a solution there is sufficient movement in certain parts that is not conclusive to precision. Dowels need very tight tolerances because even a slight error can sum to something way off, just look at one of those asian knockoffs of the dowelmax which looks identical but there is a slight non symmetry in the drill block so alignment of the opposing workpieces means that joints either don't close or require excess clamping force.

The word not yet mentioned in these discussions is void, with a dowel it is a tight fit all round, with a sloppy domino albeit in just one plane you will end up with voids, if you introduce deliberate sloppyness to achieve alignment you must also be introducing weakness, whether this effects the final joint in it's given application is another question.

If we compare 8, 10, 12 and 14 mm domino's all at 100 mm length the glue area on the flat sides are all equal, just spaced further apart. The difference in glue area is that given by the radiused ends, the 8mm gives 2500mm^2 and a 14mm gives 4400mm^2 so once the slot is wider this surface area is no longer in contact for gluing and all these domino's are held in place by the same glue area.

The major contribution to shear strength is the actual volume of the domino, so a 14mm will have much more strength than an 8mm domino but in the sloppy mode both retained by the same area of glue, with a void in which to potentially move if the glue fails.

The actual joint strength has to be a balance of material removed to fit the domino versus amount of material left so just fitting the largest domino could result in a weaker joint, but an interesting question is what has the best shear strength, a single domino or four dowels? Any advanced users of Matlab out there could potentially model this!

If you look at an 8mm domino compared with 8mm dia dowels, the domino has 3 times the x section area but only twice the gluing area. If you introduce slop in the domino so that there is no effective glue strength on the radiused end then the effective glue area is the same as the dowel.

 

[Jameshow]

@Spectric I can see the Engineer coming out, personally I can't recall ever using the "sloppy" settings on any thing I've made using domino's from the 4mm to purpose made ginormous ones.

Any way I'm much happier using this to make proper holes!

View attachment 146245

Nice is that cheaper than a domino?!!

 

[sometimewoodworker]

The word not yet mentioned in these discussions is void, with a dowel it is a tight fit all round, with a sloppy domino albeit in just one plane you will end up with voids, if you introduce deliberate sloppyness to achieve alignment you must also be introducing weakness, whether this effects the final joint in it's given application is another question.

Theoretically you are, without doubt, correct.

From the information I have gleaned antique furniture has, for the most part, excellent visible joints (only the good looking will survive) however the non visible joinery is often rather sloppy by today’s standards and has voids.

Joints are constructed so that the force acting avoids putting strain on a joint where there is any perceived weakness. For example if I were building a room door I would not use the wiggle settings. however when constructing cabinets I use wiggle on most of one of the 2 pieces.

In all the joint testing I have seen none of it has tested the theory that the wiggle can cause failure due to the voids. Given that virtually all modern glues, (I exclude CA) with correct amounts, are stronger than the wood they are used in. I strongly suspect that any testing would prove that the voids make no significant difference in joint strength.

I would certainly be interested in looking at the data produced by such a test and would happily accept that my theory is mistaken. Possibly Matthias Wandel could be persuaded to do such a test using his pantorouter, I don’t think he has a Domino machine, but using actual Festool Dominos as the embossing on those allows for glue to be retained when inserting them

 

[Doug71]

In some situations if I think a bit of wiggle room is needed for the dominos I leave the tool on the tight setting and make a plunge a mill to the left of my line then another a mill to the right of my line, I find this is generally more than enough and saves switching settings on the tool.

 

[Nelsun]

and saves switching settings on the tool

and saves forgetting to switch settings on the tool. Fixed it for you

 

[Spectric]

there is no effective glue strength on the radiused end then the effective glue area is the same as the dowel

and now you may be using four or five dowels !

 

[Derek Cohen (Perth Oz)]

would a biscuit jointer be a better option-as long as you use the same face for reference then once centred they give you a little wiggle room . I really like the Festool domino but the cost rules it out . I’ve had the Dewalt biscuit jointer for over 20 years and although not used every day I’m still on the same blade .

I have the Domino DF500, however the biscuit joiner is better for mitres like this ...

A choice of tenon vs spline.

Regards from Perth

Derek

 

[Hornbeam]

and now you may be using four or five dowels !

If you introduce slop in the domino so that there is no effective glue strength on the radiused end then the effective glue area is the same as the dowel.

I think you are mis quoting me. My point was that is you introduce slop then there is no glue strength at the radiused ends because it is now a void. The surface area of the flat part of a domino is about the same as the total circumferential area of a dowell of similar diameter to the domino
Dowels, biscuits and dominos all work at strengthening a simple butt joint (any grain orientation) How well they perform will depend upon the joint geometry and the way the joint is stressed

 

[Spectric]

I think it works out at 2 dowels will equal roughly 1 domino of the same size and length as to total surface area, but there are so many variables that it becomes hard to work everything out.

For a given joint if you increase the size of the domino then upto a point you will get an increase in strength but beyond a certain point it will become weaker because you have removed so much material that not much is left. This applies to the number of dowels used in a given pattern, only beneficial upto a certain number but then it raises another question, are more smaller dowels / domino's stronger than fewer larger dowels / domino's ? Thinking along the lines of a load shared .

 

[HOJ]

the biscuit joiner is better for mitres

I also use biscuits, made an Oak staircase last year with 130mm square newels, solid timber wasn't going to work as it would have been air dried and liable to move all over the place so I used ex 42mm KD boards and boxed them with mitred joints and biscuits for alignment, oh and lots of glue:

Nice is that cheaper than a domino?!!

Probably, its a serious piece of hardware for the money they do go for.