Plywood cabinet assembly: screws vs. dominoes

[Peter Kelly]

I am planning on building replacement bathroom cabinets from pre-finished maple plywood.
This will be my first build of conventional cabinets. They will be Euro style, using the LR32 system for hinge holes and shelf pin holes.
I've just watched (again) Greg Paolini's video of cabinet building, and Brett Shiveley's Festool video series on cabinets.

I have all the tools needed to do Domino or pocket-hole joints, and step bits for Confirmat screws; also I have an as-yet unused Milwaukee 23 gauge pin nailer I can use to tack the parts together.

It seems to me that for these cabinets, where all ends will be hidden, that dominoes are overkill and screws, such as Greg Paolini uses, would be more than adequate. I know confirmat screws are recommended for MDF, but are not bugle-head GRK screws fine for assembly of plywood cabinets (#8 x 2 inch?)

I haven't yet tried using the GRK screws without pre-drilling; I can try and see if that seems to produce a neat result.

Dominoes are handy to keep everything aligned when assembling and only take a minute or two to add. No glue really required if you're also using Confirmat type fasteners.

Unless you're planning on using Medite MR, I'd avoid MDF in a bathroom. 

 

[Packard]

I have a data-driven mindset.  I like to see numbers, pounds, etc. to support statements.  That is why I followed the advice from those studies. 

I have never seen any data on racking strength for pocket holes.  I do know that I can break apart face frames with two pocket holes in them fairly easily.  For racking strength, they depend upon the body of the screw.  That is why the confirmats, with their really thick shaft fared so well in the tests. 

The pocket hole screws I use (I do use them) are about the same thickness as drywall screws.  In my mind there is no reason that they should fare better than the drywall screws.  I will look on line to see if there are any actual tests done on that.

 

[Packard]

I could find data on pocket holes vs. dowels vs. tenons. 

As you might expect dowels were stronger than pocket holes and tenons were at the top of the heap.
https://woodgears.ca/joint_strength/pockethole.html

Dowels were about 50% stronger than pocket holes and mortise and tenons were 100% stronger. 

But sometimes stronger is not better.  Sometimes stronger is just stronger.  For face frames, I think stronger is not required.  Pocket holes are fine.  For other applications maybe not.

Surprising (to me) was the observation that glue did not improve the strength of pocket hole construction.  So if you are using pocket holes, glue may be a messy, but unnecessary step.

 

[ChuckM]

I could find data on pocket holes vs. dowels vs. tenons.  Snip.

I don't use pocket-hole joinery, only Dominoes and M&Ts. This from FW:

 

[Packard]

One of my first face frame projects featured full bridle joints for the face frames and in place of the stub tenons on the rails and stiles of the drawer fronts.  Insanely I cross pegged all the joints with a single square dowel in the center of each junction. 

A clear case of "stronger is stronger, but not necessarily better".  It also took way to long to build.

The poundages listed in that chart seem exceedingly large.  Most of the tests I've seen see failure under 400 pounds. 

Can you link us to the article?  It seems worth reading.

I do have a beadlock jig.  Slow to use but as easy as a dowel jig except you have to drill 10 holes per joint.  I built a screen door from 5/4 pine years ago.  It is not showing any weakness in the joints.  So entirely satisfactory.  But I've seen tutorials using pocket holes to build essentially the same thing.  So, typical of me, I probably over-built it.

A while back I tore apart a site built vanity in my 1953 built home.  It was built entirely with butt joints and hand-driven nails.  I would note that it was fully intact when I tore it out and it was a bear to break down.  I have newfound respect for nails.

 

[ChuckM]

Snip.
Can you link us to the article.  It seems worth reading.
Snip.

The joinery test is published in Fine Woodworking issue #203. The magazine doesn't provide the full article on its non-member website.

 

[squall_line]

A while back I tore apart a site built vanity in my 1953 built home.  It was built entirely with butt joints and hand-driven nails.  I would note that it was fully intact when I tore it out and it was a bear to break down.  I have newfound respect for nails.

The cabinets in my 1961 home all appear to be site-built, butt-and-nail.  I don't think they're going anywhere any time soon.

About a year ago, I removed a set of site-built built-in fixed-height bookshelves from a law office; all of the shelves were through-nailed to the uprights; 90 degrees on one side and toe-nailed from the other (because there was no direct access to the other side once it was in place).  It wasn't going to rack without significant persuasion.

There was an adjustable built-in shelf on the other side of the office with pilasters instead of nailed shelves, and we had to nail cross supports on the back to move it without it falling apart more than it already was.

 

[Stan Tillinghast]

Well, a lot of comments!
I had time this morning after applying a coat of Osmo to my mocked-up door panel pieces. BTW I'm making those doors with Sedge's method using stiles grooved the entire length. However, I find using 8x50 dominoes gives me a very strong door that will stay together while I switch out parts to look at different wood combinations.

I found Greg Paolini's Festool-sponsored video series on cabinet construction, which is newer than the earlier video I watched in which Greg used screws, with parts tacked in place with a brad nailer.
In the new video, naturally Greg used dominoes for everything!
No more dovetail drawer joints; face frame dominoes on, etc.

I suppose I will use dominoes, partly because it makes machining batches of parts and assembling them later easier. Also as a skill-builder.

I calculated the sheet goods needed for the three cabinets (2 30-inch with doors, one 24-inch with drawers) needed for each bathroom (counter for master and guest bath will be similar except 22 inch depth in the guest bath).

I've decided, as I think I indicated above, to start collecting supplies now as the supply chain issues will only get worse for a while. Some places are limiting orders for Blum hardware.

 

[ChuckM]

Snip.
Also as a skill-builder.
Snip.

Especially if you made a mistake on this plywood project, it wouldn't hurt as much.

I know indirectly a guy who sold his DF500 within a year of the purchase, claiming that the machine was difficult to use. The truth was that he hardly used it. Anyone who has used a dovetail jig, such as the Leigh, knows what lack of practice means. Once past the learning curve, no other joinery system can beat the Domino machine. It's an expensive machine that should be used in every suitable opportunity that's available. I use it to build boxes, trays, cabinets, tables, shelves, chairs, etc.

 

[semenza]

    I am not sure I see the need for face frames and cabinet boxes to be able to withstand however many bazillion pounds of force that may be required to break them apart on purpose. Yes, stronger is better but there is also ...... plenty strong enough.  And I am pretty sure any of the methods or combination of methods in this topic will make them strong enough.

    Choose the method that will be the easiest to build them using the tools you have.

Seth

 

[Packard]

Fasteners for cabinet boxes have two functions:

1.  Hold the joints together
2.  Prevent racking

Dominoes and dowels (with glue) do a good job on both.
Confirmats do a good job on both but are exposed.
Conventional screws (drywall or construction) do a good job of holding the joint together, but a poor job on racking
Pocket screw also do a good job on holding the joint together, but a poor job on racking.

Conventional screws are fast and cheap, but being exposed and lacking racking strength fall short for me.

Pocket screws are hidden and there is a place for them in cabinet construction.

Dados and glue.  The dadoes locate horizontal boards accurately but offer poor racking strength.  There are no exposed fasteners.  But they gain their strength from the total construction contributions.  As a standalone joint, it comes up short.

My preference is (lately) dowels.  They are fast and cheap and offer excellent racking strength.  For Euro cabinets they can be completely hidden.  For face frame, they can be quickly (with no required jigs) through doweled. 

Dominoes are less accessible (pricy equipment required) and the dominoes are far more expensive than dowels.

Beadlock requires expensive tenons (built or purchased) and are tedious to drill out (10 drillings per tenon) and probably have no place in cabinet construction.

 

[Crazyraceguy]

    I am not sure I see the need for face frames and cabinet boxes to be able to withstand however many bazillion pounds of force that may be required to break them apart on purpose. Yes, stronger is better but there is also ...... plenty strong enough.  And I am pretty sure any of the methods or combination of methods in this topic will make them strong enough.

    Choose the method that will be the easiest to build them using the tools you have.

Seth

Yeah, that's kind of what I got out of Packard's post above too.
The term "good enough" is often mocked or looked down upon as being marginal or barely adequate, but I think it applies here very well.
Base cabinets need to be strong enough to hold up the countertop and whatever you reasonably would put on it and uppers need to be strong enough t actually stay on the wall and the shelves not sag. Beyond that is overkill in terms of time and materials used.

My house was built in 1929 and still has most of the original kitchen cabinets. They are "built-ins" that were done on-site with solid wood, with the exception of the doors. I think they were replacements at some time though? One of them is rail/style frame with glass and the rest are 3/8" rabbet overlay plywood. The cabinets themselves are painted white as is that glass door's frame. The flat plywood doors are well aged clear lacquer. I assume that they were originally frame/panel and painted too?
Point being that they have been there over 90 years.....good enough.

 

[Packard]

I compulsively over-build everything.  But recently I made a bathroom medicine cabinet using the crudest of joinery.

I used butt joints on 3/4" thick poplar.  Glue and 15 gage nails from a nailgun.  Filler for the nail holes and paint. 

The door as regular rails and stiles with stub tenons. 

It is on the wall.  It seems very sturdy.  It went together quickly.  No regrets.  But I probably won't do that again. 

I am not fond of 18 gage nails for joining boards.  The nails seem to follow the grain and veer off to the side sometimes coming through the side of a panel.  The 15 gage nails don't do that.  Since I was filling the holes anyway and  painting, there was no reason to use the 18 gage nails.

 

[ChuckM]

Snip.
I am not fond of 18 gage nails for joining boards.  The nails seem to follow the grain and veer off to the side sometimes coming through the side of a panel.  The 15 gage nails don't do that.  Since I was filling the holes anyway and  painting, there was no reason to use the 18 gage nails.

Deflection and blowout - David Schmidt offers this useful guide on brad nails vs finish nails, as published in the Wood magazine.

 

[Crazyraceguy]

The same goes for narrow-crown staples, they need to be shot perpendicular to the edge.

 

[semenza]

I just want to add that I think testing for this type of thing can be used for comparison purposes and to weed out things that are simply "not good enough". But most common types (maybe excepting cheapo factory cabs.) of cabinet box and face frame joinery will all be strong enough.

Seth

 

[tsmi243]

weed out things that are simply "not good enough".

Amen.  Even the "junk" cabinets take some work to remove. 

I think maybe a good studfinder is the real key to quality cabinetmaking.

 

[4nthony]

I found Greg Paolini's Festool-sponsored video series on cabinet construction, which is newer than the earlier video I watched in which Greg used screws, with parts tacked in place with a brad nailer.
In the new video, naturally Greg used dominoes for everything!

Is that the "Mastering Built-In Furniture" series posted in the Popular Woodworking channel or is there another?

 

[fshanno]

Amen.  Even the "junk" cabinets take some work to remove. 

I think maybe a good studfinder is the real key to quality cabinetmaking.

Amen to that!  And for me finding the stud is not the issue.  Finding the CENTER of the stud is the issue.

 

[fshanno]

Time is not really an issue is it?  Once you've made this case you're done right?  You've already spent more time thinking about it than the time difference between the slowest and the fastest methods.

Since you have a Domino it seems like a no brainer.  A lot more fun.  Less mess.  Way cooler.  And you have to clamp pocket holes twice, once to make the pocket hole and again when you drive the screw.  You just have to leave the clamp on longer with a domino.

Any of the methods is strong enough for built in cases.  A nailed butt joint with no glue is strong enough.  4 or 5 dominos with glue in the mortises will do just fine. 

Now if you didn't have a Domino then pocket holes by all means.  First of all, every household should have a pocket hole jig.  It's like duck tape.