Through dowels vs blind dowels in plywood

[Cooler]

Has anyone ever used through dowels for constructing a cabinet box from 3/4" plywood?

In my mind it will be stronger than blind dowels and for face frame construction the fasteners will be hidden by an end panel or another cabinet or a wall.  

It would also be much faster with half the number of holes to drill.

And clamping will be easier with each dowel put in singly it will nor require much pressure.  

Any thoughts?

[fredhargis]

I have, sort of. I just built all my shop cabinets that way, but instead of dowel I used a Domino loose tenons. It worked really well, and did make the construction a lot faster. I'm not normally in a hurry...but in this case I was. I suspect that the dowels will work just as well, though it may take a few more of them to get as much glue surface. BTW, I built some of the drawer boxes that way as well...at least for the back joint. The fronts were drawer lock joints.

[rwe2156]

I just screw all my cabinet boxes together.  Never been an issue I don't usually even use glue.

I really like pocket screws for face frames. Face frames can also be attached to the box with pocket screws or as Fred said, Dominoes or dowels.

HUGE advantage of screws for both boxes and ff's is you don't have to clamp up and wait for glue to dry. This is BIG when you're doing a production run (time saving + you don't have to worry about running out of clamps.)

End panels can be addressed by applying a veneer, 1/4" ply or better yet, a panel that matches the doors.

[Phil Thien]

I’ve done blind but never through. The blind were strong I’d think the through would be even more-so.

[Cooler]

I used to use dadoes.  After reading the lab tests run by the RTA furniture association in Europe I stopped.  It provided the poorest racking strength of all the fasteners tested (including those crappy 1/4 turn metal dowel things).

Of course racking strength is not much of a factor in kitchen cabinets where the wall becomes a structural member.  

In order of strength (weakest to strongest for racking strength only) for a single plywood board attached at one end to another plywood board and similar results with particle board:

• Dados (failed before the test equipment could register any load)
  
• 1/4 turn metal dowels
  
• Drywall screws
  
• Confirmat screws (a close second to dowels)
  
• Wood dowels
  

The kitchen cabinet manufacturer's association made a similar test with similar results.  (Dados were at the bottom of the list).  Interestingly both associations' tests recommended against any fastener less than 2" from the corner of the board.  Apparently the fastener would split open the board if it were not supported on both sides by at least 2" of board.

Confirmat screws are large body screws that require special stepped drill bits.  They function as both a dowel and a screw.  They can be removed and inserted several times and still retain holding strength.  A handy alternative to clamping.

Confirmat screw:

[Phil Thien]

I used to use dadoes.  After reading the lab tests run by the RTA furniture association in Europe I stopped.  It provided the poorest racking strength of all the fasteners tested (including those crappy 1/4 turn metal dowel things).

Of course racking strength is not much of a factor in kitchen cabinets where the wall becomes a structural member.  

In order of strength (weakest to strongest for racking strength only) for a single plywood board attached at one end to another plywood board and similar results with particle board:

• Dados (failed before the test equipment could register any load)
  
• 1/4 turn metal dowels
  
• Drywall screws
  
• Confirmat screws (a close second to dowels)
  
• Wood dowels
  

The kitchen cabinet manufacturer's association made a similar test with similar results.  (Dados were at the bottom of the list).  Interestingly both associations' tests recommended against any fastener less than 2" from the corner of the board.  Apparently the fastener would split open the board if it were not supported on both sides by at least 2" of board.

Confirmat screws are large body screws that require special stepped drill bits.  They function as both a dowel and a screw.  They can be removed and inserted several times and still retain holding strength.  A handy alternative to clamping.

Confirmat screw:

Thanks for posting that.

I agree that with backs installed, and after ganging a few together, and screwing them to the wall, that racking is of extremely little concern.

OTOH, many of these tests might be performed on flat-pack cabinets, where they need to make sure the cabinet won't rack/split during assembly by inexperienced Ikea-type consumers?

So pretty critical that the thing doesn't split apart before the back is installed.

I'm installing some inexpensive commercial pre-assembled cabinets with my son-in-law now.  The cabinets are installed, actually, they're waiting for counters.

I did ask here whether we should install individually or gang rows of face frames first.  I'm not sure there was a consensus.  We quickly learned ganging them together by flushing/screwing the face frames provided the best opportunity at getting everything level.  That likely has to do with the inexpensive cabinets and wavy floor.  If I ever do my own kitchen, I will install on plywood frames.

I got points for scribing.  I gotta tell you that little Porter Cable single-handed belt sander makes scribing to old plaster walls very simple.

[jteneyck]

If you are talking about kitchen cabinets I would never even consider dowels unless I had a line boring machine, which I do not.  These kinds of cabinets are supported by the back and the faceframe, if used, as was said.  I use butt joints with biscuits for alignment, and glue and screws to hold the boxes together.  My own kitchen cabinets are Melamine boxes, a material many won't use "because it's cheap particle board that will fall apart in no time".  They are now almost 25 years old, and the boxes are still as solid and look as good as when I installed them.  I made the drawers out of Melamine, too, held together only with glue and biscuits, running on self closing slides (but not soft close) and they look just as good.  I'm in the process of replacing the doors and drawer fronts, but the boxes and drawers are staying put.   


I usually use mortises and loose tenons to put together faceframes and attach them with biscuits and glue using Norm's method, or pocket screws if they won't show.  

Dowels?  Sure, plenty strong, but that wouldn't justify their use to me for kitchen cabinets.  

John

[Cooler]

If you are talking about kitchen cabinets I would never even consider dowels unless I had a line boring machine, which I do not.  These kinds of cabinets are supported by the back and the faceframe, if used, as was said.  I use butt joints with biscuits for alignment, and glue and screws to hold the boxes together.  My own kitchen cabinets are Melamine boxes, a material many won't use "because it's cheap particle board that will fall apart in no time".  They are now almost 25 years old, and the boxes are still as solid and look as good as when I installed them.  I made the drawers out of Melamine, too, held together only with glue and biscuits, running on self closing slides (but not soft close) and they look just as good.  I'm in the process of replacing the doors and drawer fronts, but the boxes and drawers are staying put.   


I usually use mortises and loose tenons to put together faceframes and attach them with biscuits and glue using Norm's method, or pocket screws if they won't show.  

Dowels?  Sure, plenty strong, but that wouldn't justify their use to me for kitchen cabinets.  

John

I would not use the melamine clad particleboard, but for a different reason.  I've made bookshelves from that material and it held up well.  But the perception of melamine cabinets is that they are "cheap", though way better than the vinyl clad particle board that my current cabinets are made from.  

But I plan on selling the house in the next few years and everything I am doing in the house is with an eye towards that sale.  So I think plywood boxes and soft close hardware will be on the menu.  

It will also influence design, and as white is the most chosen finish for cabinets, that will be the color I will choose.  

I always use through dovetails for my drawers and that will not change.  

I will be using pre-finished panels for the first time and they won't take glue at all.  So I think dowels are a very reasonable choice.  

In any case I do like the confirmat screws, especially in particleboard.  They never split the board and they have good holding power.  But way more expensive than drywall screws.

[jteneyck]

I would not use the melamine clad particleboard, but for a different reason.  I've made bookshelves from that material and it held up well.  But the perception of melamine cabinets is that they are "cheap", though way better than the vinyl clad particle board that my current cabinets are made from.  

But I plan on selling the house in the next few years and everything I am doing in the house is with an eye towards that sale.  So I think plywood boxes and soft close hardware will be on the menu.  

It will also influence design, and as white is the most chosen finish for cabinets, that will be the color I will choose.  

I always use through dovetails for my drawers and that will not change.  

I will be using pre-finished panels for the first time and they won't take glue at all.  So I think dowels are a very reasonable choice.  

In any case I do like the confirmat screws, especially in particleboard.  They never split the board and they have good holding power.  But way more expensive than drywall screws.

If you use biscuits or Dominos you can glue prefinished plywood; no different than what I did with Melamine.  For a whole kitchen worth of cabinets you could buy a Domino.  It would be so much faster than using dowels, and you could sell it for likely 75% of what you pay for it afterwards if you can't justify keeping it.  

Through the whole process you should remember that kitchens and baths are the most often remodeled rooms in a house and the time most get changed is just before or after a home is sold.  Regardless of what you think looks good, people will rip out something that doesn't appeal to them and lower their offer so they have the money to do so.  Be careful how much love and money you lavish on this.  Of course, if you plan to stay for 10 years, have at it.  

Good luck.  I look forward to seeing pictures along the way.  Speaking of which, how's the bathroom tearout coming along?  

John

[Cooler]

If you use biscuits or Dominos you can glue prefinished plywood; no different than what I did with Melamine.  For a whole kitchen worth of cabinets you could buy a Domino.  It would be so much faster than using dowels, and you could sell it for likely 75% of what you pay for it afterwards if you can't justify keeping it.  

Through the whole process you should remember that kitchens and baths are the most often remodeled rooms in a house and the time most get changed is just before or after a home is sold.  Regardless of what you think looks good, people will rip out something that doesn't appeal to them and lower their offer so they have the money to do so.  Be careful how much love and money you lavish on this.  Of course, if you plan to stay for 10 years, have at it.  

Good luck.  I look forward to seeing pictures along the way.  Speaking of which, how's the bathroom tearout coming along?  

John

I have three projects going now.  New soffits; new flower boxes and the bathroom.

The soffits have to get done in the nice weather so it is taking precidence.  But I am shipping out about 75 pounds of tile each week.  I think about 4 more weekends and it will be done.  As soon as I hit the 75 pound mark I switch to one of the other projects.  

I'm never in a hurry.  I break jobs down to manageable "bites" and eventually I get them done.  I finished the half bath and I am pleased with that (except for the baseboard heat which I just painted and it looks distinctly out of place here.  I will make new baseboard covers shortly.  (Another small project.)  I will post some pics of that.