Bigger Domino Machine

[woodguy7]

I am making that window, an oak entrance screen & oak internal door for a local contractor.  He is working on a large renovation for a drama group.  They must have got a lot of grant money from somewhere, that window alone is near 5k + vat.

I will take some pics when i make the screen + other door & post them here.  Will also try to get some pics when they are in situ.  Thanks for the comment, good to see you back.  Have you been away or is Daisy keeping you busy    (it is Daisy isn't it ?)

Woodguy.

 

[Mac]

Haha, yeah, Daisy's keeping me pretty busy, along with my other two!  [crying]

I'll look forward to more pictures, I like your work.
Cheers,
Rick

 

[fshanno]

I presume that when you say use shorter screws you are meaning that the screws will give way before the joints fail  [eek]

Sorry but i want a door to stay together & swinging even if 2 full sized adults are swinging on it.  I still think that anyone using this meathod to construct an entry door either does not have the equipment or the ability to do it the propper way.  Don't want to sound arrogant but that is how i feel about door construction.  I would gladly let 2 full sized adults swing on any door I have made & hung  [smile]

Woodguy.

How much load should a 1-3/4" entry door carry?  Depending on the width of the rail you can get 4 or 6 10mm dominoes in each joint.  Do you really think they would fail a reasonable test?

 

[woodguy7]

Hmm, hard to say.  I know there is generally not that sort of load on a door but i like to be on the safe side.  If you want to make a door that way then fine, do what you think is best but all i am saying is that i wouldn't.  I don't have all the answers to door construction but i have a good idea of what i think will work well.

Cheers, Woodguy.

 

[Notorious T.O.D.]

The door I made for my dad's front entry is 1 3/4" thick cherry with raised panels.  It is 48" wide and 96" tall...so there is no problem getting the furniture or caskets in and out...LOL.  I would estimate the weight of the door without any hardware at 150-175 pounds.  It hangs on four 4" ball bearing hinges and swings like butter...

Best,
Todd

 

[cje]

I've seen several domino strength tests, but can't remember where. I'm sure there was at least one here as well. Using google I ran into this one, new for me and with quite an impressive result. I bet it's sufficient for a door, but the setting time of 7 days for the glue might be too much time consuming for the average FOG member. Alas, being an ambitious-but-restrained-on-budget hobbyist Festoolian the domino is beyond my reach.

Best, CJ'60

 

[mouppe]

I would also be concerned at the effect over time of the door being opened and shut, especially with the odd bang here and there. Would this shake loose the domino and its glue joint? I am unsure how a strength test could measure this, but surely a loose tenon does not have the strength of a solid tenon.

 

[woodguy7]

but surely a loose tenon does not have the strength of a solid tenon.

Thank you, exactly what i I'm trying to say.

Woodguy

 

[jonny round boy]

but surely a loose tenon does not have the strength of a solid tenon.

Thank you, exactly what i I'm trying to say.

Woodguy

If your comparing a loose tennon and a solid tenon of the same same size, then I doubt very much there'd be a difference.

But in a door like the one illustrated, the tenons are much bigger than the biggest dominoes so will obviously be stronger.

 

[Notorious T.O.D.]

Yes, if the loose tenon is the same size as the solid tenon and the glue is actually stronger than the wood, which I think most would agree upon.  Then the loose tenon should be equally as strong as the solid tenon if both are well fitted and glued well.  Perhaps the loose tenon might beeven stronger as the length and glue area increases as the wood for the tenon can be selected for straight grain strength while the solid tenion might not have as straight of grain.

Best,
Todd

 

[mouppe]

Even if the glue is stronger than the wood, with a loose tenon you have two ends that need to be tight fitting, whereas with a solid tenon, you obviously only need to concentrate on one end. This is especially if you use the domino with the larger size mortise for one end.

 

[woodguy7]

The thing is, if using the Domino i understand that you can move sideways to make wider slots but the deepest you can get is something like 28mm.  Compare that with a full sized tenon of an average of 120mm & usually 16mm thick compared to 10mm.  And the fact the tenon can be wedged.

Woodguy.

 

[Tim Sproul]

But in a door like the one illustrated, the tenons are much bigger than the biggest dominoes so will obviously be stronger.

In general, wood joints have at least 2 members.  The strength of the joint depends on both (or all when more than 2) members.  Making one member of the joint larger than the other does not necessarily mean a stronger joint.  We can carry the example out to the ridiculous to illustrate.  If you mill the mortise so that only veneer thin walls are left, and so use a correspondingly huge tenon, that joint will likely fail during assembly, never mind during use of the door.

Sometimes, rather than making a large single joint, multiple smaller joints combine to be more effective and stronger.

 

[Rob-GB]

May I try to clear up a misunderstanding or misconception that appears, to me anyway, to be surfacing in this thread?

We all agree, I believe, that modern glues are generally stronger than the wood itself.

We therefore know that the longer the glueline the stronger the joint, hence the range of router and spindle/shaper cutters that are designed to do just that.

So multiple Dominoes = more glue line, therefore strength. Correct. [big grin]

Large traditional mortice and tenon (with haunching as required) = large glue line therefore strength. Correct. [big grin]

Same traditional mortice and tenon (with haunching as required) plus wedges = even larger glue line and (what is termed in the UK at least as) a mechanical fixing. The wedges create a bonded dovetail effect. Surely then, this is a stronger joint than the other two examples?  [scratch chin]

Yes making the tenon too fat will be detrimental, but, the rule of thumb used in any workshop I've been in, in the UK or Germany, is that the tenon is 1/3 the thickness of the timber. (a useful practice for determining the domino size best suited for the task, IMHO)
This then gets translated to the nearest size of morticer chisel and bit available, just above or below that determined size.
For really thick timbers where the tenon would be, say, over an inch thick, then the use of double tenons would probably come into practice. There is a science of sorts that has been worked out over decades of carpenters and joiners trying to find the best solution to each new task they undertook, those that worked got passed on, then the theory became practice.  ;D
When it comes to the Domino, I guess we are walking that same path those early carpenters did, the questions, "will this work?" or "what if we did..." you can just imagine the debates in the local inn over a mug of mead... [laughing]

Just my thoughts.

Rob.

 

[Nigel]

      Spot on Rob,

                        Another point is a long tenon adds strength across the stiles on a hoizontal plane,stops them cupping or flexing.I,m surprised nobody's mentioned a pegged mortice and tenon?Better than wedges I reckon.

 

[Rob-GB]

       Spot on Rob,

                         Another point is a long tenon adds strength across the stiles on a hoizontal plane,stops them cupping or flexing.I,m surprised nobody's mentioned a pegged mortice and tenon?Better than wedges I reckon.

I recently worked on some really old doors that were glued up with hide glue, the glue had long since failed but the tenons had been drawer bored pegged and wedged. I suspect the drawer bore was done due to the lack of sash cramps, I am not sure when iron ones were first introduced [scratch chin] but there were other methods employed.

The downside of relying on just pegging them is the relatively small area the peg acts on and the diameter of the peg used to provide strength.
On large timber frame, post and beam, projects, pegs of 3/4" and 1" are commonly used to drawer the joints tight but once the building is erected they have very little work left to do, some old buildings I have worked on the pegs are loose and no longer doing anything at all!

Back on topic..... A Domino of 1/2" thickness would get a lot of use, by me, in static joinery work such as door and window frames, handrails and lantern frames. As long as the machine was as easy to use as the current version. ;D

Rob.

 

[woodguy7]

Rob & Nigel

Both make excellent points.  I don't think pegs would be better that wedges for the exact reason Rob mentions.  I do use draw pegging when connecting newel posts the a stair stringer.  There is much more timber to hold the peg & it does work really well.  I always counter bore with a 16mm forstner bit first then drill a 12mm hole for the peg itself.  Punch the peg 10mm below the surface then plug the 16mm hole.  I think it looks better as i don't like to see end grain of the peg.  It is for this reason that i wont peg a door tenon as the cheek is only approx 15mm thick on a standard door.  Off course, in the old days they liked to have the peg showing but the wood shrinks different ways so when the thickness of the door reduces the peg wont as it is long grain.  But as Rob says, it will shrink in diameter & become slack.

Woodguy.

 

[Notorious T.O.D.]

Rob, would the extra .1" of a 1/2" Domino thickness really add that much more than the 10mm which is already available or is it a longer length (depth) or wider width that we would really like to see?

If we go by the rule of thirds, which is reasonable then a 1/2" Domino would be for material 1 1/2" or greater while the 10mm would be for 30mm or thicker.  I guess I am just asking is it the thickness that we need or greater width and depth?  And are we talking about something that would be only used by those building larger items with heavier timbers such as house doors, perhaps windows and maybe large tables?

Best,
Todd

 

[Tim Sproul]

My point was simply to remind folks that a wood joint must be balanced to have the greatest strength.

 

[Rob-GB]

Todd,
The Dominoes get wider and longer as thickness increases so it is the cumulative effect I was thinking about. Traditional tenons are worked out for size by the components being joined, it gets a bit technical though. I'll try and write up something with cad illustrations when I get back from holiday, and post it in a new thread. I still can't see even 1/2" dominoes being sufficient on entrance doors and the like, only time and a brave soul will prove otherwise.

Tim, 

My point was simply to remind folks that a wood joint must be balanced to have the greatest strength.

That you did, I felt we needed to look at the subject in more detail, I hope I have not offended you in any way. Threads can sometimes go off at tangents through misunderstandings.

What we have with the FOG is the chance to learn how solutions to construction problems are approached and overcome around the world, which to me is fascinating. In the UK we are or were lucky to have the apprenticeship system that was designed to give people a good grounding in the how and why of the job, based on a long history of woodworking skills and techniques, it seems to be lacking somewhat now judging by the last lot of apprentices I have worked with. [sad]  I was fortunate to have really good guys for my on site and shop training and a couple of good lecturers at college. In my day we were taught carpentry, joinery and wood machining; now it is all separate, crikey I sound like an old man [jawdrop] it was only 27 years ago!!

Best regards, Rob.