Domino Size and Strengh Question

[Archis]

Newbie Alert [big grin]

I've read everything I could find about sizing the dominoes but still need some advice on a light duty application.  I'm building a slat style shelf for my wife out of 2 x 1.25 Cherry.  It will consist of (2) 23 inch stiles and (7) 19 inch rails that will form a 23 x 23 shelf.  Since my machine came with a number 5 bit I'm planning on using a single number 5 domino for each joint.  The shelf will hold < 30 pounds in the form of 3 potted plants.  Will these joints be sufficient for this application?

Thanks in advance!

 

[semenza]

Hi,

Welcome to the FOG!  [smile]

So each shelf will be several seperate slats, each slat will have one Domino?

If I am picturing it right that would probably be fine.

Seth

 

[jacko9]

I don't see any issues with a single # 5 tenon.  You might want to consider purchasing the Domino Assortment with the cutter set for future work.

Jack

 

[Archis]

Thanks for the welcome and the advice. 

Once I get my credit card off of life support from the domino joiner purchase,  I will be getting that domino assortment and bit set [wink]

 

[Stone Message]

Hi Archis and welcome

My woodwork (and whole life) have changed because of the Domino machine. Your proposed idea will be fine, it is amazing just how strong a well made Domino joint can be.

Take Jack's advice and go for the assortment systainer (tell your wife that you have bought it as you give her the plant holder) it will open up so  many more opportunities.

I am just finishing off an article for a UK woodworking magazine that is about the way that the Domino has made jointing so much easier.

Peter

EDIT> name correction

 

[jacko9]

Thanks for the welcome and the advice. 

Once I get my credit card off of life support from the domino joiner purchase,  I will be getting that domino assortment and bit set [wink]

In the meanwhile enjoy your Domino joiner with the #5 cutter. 

I have found that building hardwood furniture that I use the #6 and #8 dominos a lot.  I now have the Domino XL with the domino assortment for that machine and I can't be happier with my M&T capabilities.

Happy building,

Jack

 

[Kevin Stricker]

I would go with a #8 or #10 for that application.  You generally want your tenon to be 1/3 of the thickness if your stock, 5/4 stock is approx 30mm thick.  A #5 is only 1/6th the thickness of your stock and the rails will only be supported by 15mm of tenon.

Sure it would probably work, but I would add a pocket screw or two (you could hide them between the slats).

 

[Svar]

I’m with Kevin here. I understand the excitement about the awesomeness of Domino machine, but sadly it does not defy the laws of mechanics. A 5 mm tenon is a 5 mm tenon regardless what you use to make the hole. Just put two dominos in each joint.

 

[Archis]

2 dominoes should be easy enough, but I would prefer just 1 #10.  My concern with doubling is that this will be my first project with the tool and doubling the dominoes doubles the possibility of alignment issues.  I could use pocket screws but my luck with the plugs have been so, so.  Also if I use pocket screws, I'll have to explain to my wife why this $$$$ tool couldn't do the job by itself.  Pocket screws aren't an option [wink]

Since I'm a novice, my concern for this project is shear failure.  Are there other types of failures I should consider?   

 

[KorDes]

I would use a 10mm domino. Your stock is clearly thick enough to accommodate 25mm deep mortices. It will have a lot more holding power than a 5mm domino which only goes in 15mm either side.

I would also take it a step further and make wider domino's to suit the #3 setting.

 

[Nick C]

I assume this will be a single shelf--basically a slatted table-top shape. I would use 8mm or 10mm dominos. A single domino at each joint. WIth 14 dominos supporting 30lbs, you will have more than enough shear strength. Way more than enough.

 

[jacko9]

I agree with using a #8 or #10 domino if he actually had one of those cutters.  However, if he wants to complete a project with the #5 cutter that he has now, one Domino should be enough for the application.  If he doesn't want to buy another cutter set yet and he's nervous, he could stack two # 5 Dominos per the attached sketch.

I used two #5 Domino's for the Blade joint on a nightstand.  On a similar smaller design, I used twin #4 Dominos for the blade joints.

Send me a PM if you want details on how I cut those joints.

Jack

 

[Archis]

I ran a test on my sample #5 joint.  The domino was way off center but was at least 1/3 from one edge of my stock.  I used titebond III and cured for about 36 hours.    Sorry the photos are a little out of order.  

The first photo shows a static load test of around 150 lbs.  The bow is the assembly, the joint faired just fine.  

The second photo is a close up of the test assembly.

The third shows the joint failure at a static load of around 220 lbs which was me gingerly stepping on the assembly.  It failed as I had one foot on the assembly and was trying to place my foot on the other side of the joint.

I would use #10s if I had them, but all in all I'm now comfortable a single #5 for this project.

 

[Stone Message]

Good test - some of us said that the 5mm would be okay for your application!

Peter

 

[ajones]

Archis if you pm me with your address I will post you a cutter either 8mm or 10, then you just need a small packet of dominos to complete your project.