Barn doors with the domino?

[Seijik]

Hi guys, I have a job coming up to make some barn doors, the doors are 4m high and 2.3m wide, and will be sliding doors.

I have a df 700, and am wondering if 2 maybe 3 14mm dominos will be strong enough for the joints? unsure what the wood will be yet, but the top and bottom rails will be 150mm x 60mm and the middle rails 150mm x45mm no diagonal bracing, as per the customers design.

the other doors he had made a few years back are traditional mortice and tenon, and pegged. so im wondering if i should go with the domino and draw bore the middle domino, or just use the domino to cut the mortice and round my tenons to suit and draw bore those?

I havent done anything this big with the domino yet so after a bit of advise on if it will be strong enough and have the same longevity as a traditional joint?!

any help will be much appreciated!

 

[greg mann]

I think 2 rows of three would be best for the top and bottom rails but since the doors are not being hung on hinges they won't be subject to the wracking forces of gravity. I assume they will be running on an overhead track?

 

[JeremyH.]

They'll be providing register maybe more than strength. With large pieces of wood, that's a lot of glued surface to surface. As some say, it'll be the wood, not the joint that breaks.

Here's a door that's just glued together. The center and outsides where ran through thickness sander, separately. The center was squared, and the outside was rough first, then cut to square after gluing.

 

[Doug S]

I am still experimenting with the limits of the df 700. I made myself a pair of boarded gates, each gate 6'x6' with 5"x3" top rail and stiles and 6"x2.5" mid and bottom rails. I did a traditional m+t on the top rail but put 12mm dominos in the mid and bottom rails, think 6 in each joint. Gates have been on 6 months now and have not moved yet and as said above there is a lot more chance of movement when gates are side hung as opposed to top hung.

Doug

 

[JeremyH.]

Right. M&T helps the most against parallel pressure. It's great for registering on small stuff, and in some cases increasing overall surface area that's glued between two pieces. However it can also make perpendicular pressure create an easier break, if the T itself has the majority of the surface area. Think about a cabinet door, if it's somewhat thin and has M&T, it's not that hard to break a style and rail joint with perpendicular pressure, right where the T enters the M, because there can be little surface of the T piece mating to the M piece. I think dominoes for R&S's on cabinets would be amazing if they're not too big, the time isn't crazy, and the overall expense isn't silly (I've never compared).

M&T does have an advantage in surface area gluing compared to how many dominoes someone might use, if it's done correctly with a considerable amount of wood to work with. However if the joint is tight enough I wouldn't put it past glue and dominoes being pretty darn strong. I think that's the trick, that the two surfaces fit together at a machined quality mating, to get a dominoed registered joint to be strong for large application, without having to use dozens of them.

But what kind of barn doors are you doing? If it's an application like the door in my photo, strength isn't the biggest concern, and glue is just fine to begin with (especially with that surface area, that door won't ever break). But it would've been easier to build with dominoes, probably. Clamping can be an art-form all to itself...

 

[jmbfestool]

I personally think it will be strong enough.

I think domino joints are equally as strong as M&T of equal size. Always try and stick as many dominos as possible.

You are limited to length with dominos. 
So I make the decision based on tenon length.  If the tenon needs to be longer than the domino XL can do I would then I go M&T.

Your doors are sliding so I wouldn't be to worried........

 

[Lbob131]

Will be a heavy door/s. Strong hangers  will be the most important  and securely attached.