domino joint strength

[itri]

Dominos may not be the strongest joints  but they are good enough for furniture making.They will last for years if we use them properly.This discussion,actually makes me think  about the difference in gluing strength between hide glue and modern glue.Hide glue may not be the strongest glue but it's good enough for furniture making and when it comes to repair ,it's easier .And it's easier too if we have to repair a floating tenon joint instead of a regular tenon joint,in my opinion.

Sometimes i don't see the point when i see a woodworker who wants to built a simple furniture with "rock solid"joints ever made....well ,i think,if we don't see the joint and we want to make it fast,easy and strong enough ,the domino system is the right one.

Marty

 

[rdesigns]

Dominos may not be the strongest joints  but they are good enough for furniture making.They will last for years if we use them properly.This discussion,actually makes me think  about the difference in gluing strength between hide glue and modern glue.Hide glue may not be the strongest glue but it's good enough for furniture making and when it comes to repair ,it's easier .And it's easier too if we have to repair a floating tenon joint instead of a regular tenon joint,in my opinion.

Sometimes i don't see the point when i see a woodworker who wants to built a simple furniture with "rock solid"joints ever made....well ,i think,if we don't see the joint and we want to make it fast,easy and strong enough ,the domino system is the right one.

Marty

Good points--I suppose most woodworkers are like me to some extent; that is, I find that my projects are what I consider a balance between "best" vs "good enough."

Sometimes I do the best/strongest method because of the demands that will be imposed on the joints or materials, or just because I or the customer prefer that method.

Other times, I do what is "good enough"-- expedient for the sake of time- or material-savings. (I still use biscuits at times even though I have and love my Domino 500.) And I use the Domino in place of traditional M & T in most situations. (The frames of exterior frame-and-panel doors are an exception.)

 

[Tinker]

Dominos may not be the strongest joints  but they are good enough for furniture making.They will last for years if we use them properly.This discussion,actually makes me think  about the difference in gluing strength between hide glue and modern glue.Hide glue may not be the strongest glue but it's good enough for furniture making and when it comes to repair ,it's easier .And it's easier too if we have to repair a floating tenon joint instead of a regular tenon joint,in my opinion.

Sometimes i don't see the point when i see a woodworker who wants to built a simple furniture with "rock solid"joints ever made....well ,i think,if we don't see the joint and we want to make it fast,easy and strong enough ,the domino system is the right one.

Marty

Good points--I suppose most woodworkers are like me to some extent; that is, I find that my projects are what I consider a balance between "best" vs "good enough."

Sometimes I do the best/strongest method because of the demands that will be imposed on the joints or materials, or just because I or the customer prefer that method.

Other times, I do what is "good enough"-- expedient for the sake of time- or material-savings. (I still use biscuits at times even though I have and love my Domino 500.) And I use the Domino in place of traditional M & T in most situations. (The frames of exterior frame-and-panel doors are an exception.)

Not being an experienced door builder or having had the fun of playing with a domino, my question is: why do you not want to use the domino for exterior frame and panel doors?

I want to build such a door for my equipment barn.
Tinker

 

[Sazerac819]

Reviving this topic. 

Any domino failures that have happened recently with the festool branded dominos? 

I see so many videos on youtube where people are putting together very large doors and heavy load bearing structures such as patios.  I include a video of a build that is a wrap around patio structure on the second floor!

Some seem to be using a combination of festool dominos and also their home made dominos as seen here:


Here are some pictures of my current project.  I used the 14mm sipo festool dominos that I cut to 75 mm for 80 mm total tenon length (30 mm in the table and 50 mm in each leg) .

I have 2 dominos in each walnut leg and the 'waterfall' leg has 5 dominos. 

I'll be honest, when I dry-fitted the waterfall leg with the 5 dominos, I had a crazy hard time try to pull it back apart.  I required my wife sit on the end so I could slowly work it free again!

The table will not be heavy loading bearing, it will be along the wall in our dining area and used somewhat like a buffet table so just various food items and some dishes will be placed on the table on occasion. 

I do worry a little bit about my kids running/slamming into the legs and breaking the legs...  I guess we'll see. 

Cheers,
John

 

[grobkuschelig]

I have not had any failures where I used Dominoes up till now.
But I only used the Domino on a couple of projects, since it is a recent addition to my tool collection.

What I try to do is make my own dominos if I use wood that is different than what the standard dominoes are made out of.
I convinced myself that having dominoes out of the same species, there should not be any problems with differences in wood-movement/shrinkage...  [scratch chin]

 

[Holmz]

Was the failure in the domino, or the design, or the glue?

 

[pingvinlakrits]

I have never snapped a Domino. Not even one. I have done a couple of thousand Domino plunges and fittings since them machine came out. I have managed to break a few joints over the years - they have been either when using too thick a Domino in plywood/mdf or plunging to deep in one or both ends - or just being unlucky when putting something large together and accidentally dropping one side of a shelf before it has gone in all the way and the force has broken up the joint.

But never have I snapped a Tenon before the joint. Abiding by the Domino to material thickness ratio of 1:3 works well.

Same with wooden dowels and kitchen cabinets: it is almost scary how easy you can collapse a cabinet when you have removed the back and slam it. Flattening a kitchen in demolition takes no time.

But kitchens stay put for twentyfive years or more with heavy countertops and daily use. 

Some things don't need to be super strong, it just needs to stay together,  though it is nice when things don't discombobulate on their own volition.

I built an oak kitchen table for a family of four, with skinny legs*), extra tall since the guy who ordered it is very tall and wanted leg room. I Domino'ed the whole thing and made reinforcements where necessary since the legs are freestanding with an upper rim support on the table side. When his five year old daughter throws a tantrum she literally runs the table into the nearest wall [eek] and the legs occasionally catch something on the floor.

No problems, it is still slim and sturdy and not a wiggle in the joints two years of use and abuse later. 
I did corner brace the legs on the table side on the inside of the rim but I think that whatever the joint you need to look at the possible joint stress in daily/normal use and have some headroom on top of that but a lanky cabinet isn't meant to be tackled from the side - NFL/Oz rules style. 

*) the table, not the family.

 

[sancho57]

It's the glue that hold the joints together anyway, plus I never put 549 lbs on a joint that was domino'd.

 

[tjbnwi]

I know I've installed over 100,000 Domino's not a single failure in any way.

Tom

 

[johnmund]

Late reply on this thread, but thought I’d add my 2 cents.  I _love_ my domino 500.  I use it for small furniture mostly.  Chairs, end tables, drawers, cabinets.. it’s fantastic, revolutionary.  I got worried after reading some strength tests though and so did some testing of basic joints I use; 3/4 inch cherry using either a 8x50, 25mm deep each side, or a 8x40, 15/25mm with Festool beech tenons.  I slapped a couple joints together using my ‘fast’ glueing method which is basically glue liberally on the butt joints, glue on each end of tenon before inserting, but not in the mortises separately.  Clamp overnight.  I used 2 2ft pieces of 1x2 (3/4”x~1.5”) cherry. Result?  Hmmm.. well it’ll work fine for an end table or drawer, but had very little shear strength.  I was able to push the joints apart with not very much effort at all.  I took the ends of the right angle and just pushed them apart.  Surprisingly easy.  The tenons didn’t break, one side pulled out, splitting the wood around the joint.  Kind of surprising.  Made me seriously rethink all the places I’ve used them for structural joints.
Then I retested with more glue; I cut off the ends and recut mortises.  This time I was sure to squirt a good amount of glue in and then spread around the insides of the mortises as well as the tenons and butts.  The extra glue was night and day difference in the joint strength.  I literally can’t push it apart by hand.  I tried pushing apart the same as above and then pushing in with two hands and then pushing in with an end on the workbench.  That joint is as strong as any other part of the wood.  My thought is that just glueing the tenon isn’t strong because too much shears off when inserted into the mortise and not enough is left to bind the joint, allowing the pressure to break the bond and split the (now thinner) wood on either side of the mortise.  Liberally glueing made it as strong as any natural tenon joint I’ve ever made, or at least tried to pry apart.

 

[petar73]

I had my domino xl since 2015 and only used festool dominos once on site. I awaits make my dominos from the same material I am using with required width and fit and never had a problem.

 

[ChuckM]

There is no need to worry about wood movement in a cross-grain joint that is 2" or 3" wide. Proof? Most M&T joints work because they usually are under 4".

Festool dominoes are under 1", and people are welcome to make their own from a wood species of their choice -- but please not for wood movement reasons.