Search the forums

Loading

plywood joinery

law3's picture

I've got to build some built-in bookcases.  Plan to use 3/4" stain grade hardwood plywood.  I have read some articles about plywood joinery that include:


Butt joints w/ biscuits.


Shallow dados w/ biscuits.


Biscuits w/ screws or nails.


Continuous tongue & groove w/ glue.


Continuous tongue & groove w/ glue & nails.


Any opinions out there?


 


law3

(post #96473, reply #1 of 11)

I Hate Draging out biscuit joiners and all the other crap at jobsites.  Rout a dadoe, spread some glue, couple of brads, let dry and be done w/ it

(post #96473, reply #2 of 11)

Which joint an you handle???


Dadoes, glue and pins make fer a pretty strong joint...


This case is all dadoes.. All of it.. No biscuts...


Cake and pie...



Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!!   What a Ride!

"Some days it's just not worth chewing through the restraints"

(post #96473, reply #3 of 11)

Build everything in sections


This will give you 1½" uprights


1 or 2 fixed shelves for strength


You can use screws because they are strong, quick and will be hidden between panels


drill holes for majority of shelves (adjustable)


glue clamp and pin-nail sections together


wide face pieces over uprights stop adjustable shelves from sliding out and are usually made from solid wood, decorated? routed? ogee edges? rounded?


Arches over sections?


Crown mouldings?


 

 

(post #96473, reply #4 of 11)

Dados for joints in shear / bisuits for joints in compression.

.

Phill Giles

The Unionville Woodwright

Unionville, Ontario

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 

Phill Giles

The Unionville Woodwright

(post #96473, reply #5 of 11)

all the options work, but you need to ask yourself what will work best for this project. not all boxes are the same. if you use dados will they have any exposed edges? if so that could be a problem. will all the joints be out of sight? then why waste time on time complicated joints.

my only rule is to use some type of joint. i have never been a big fan of building casework with butt joints. even if you do not need the strength of what ever joint, they will help with the assembly.

(post #96473, reply #6 of 11)

dude is right. Pick whichever joint works best, dados being at the top of the selection offered.If sides,back are not visible, pre-assemble back with glue and pin nailer,dado shelves, add face frame(glue only) and voila.

Expert since 10 am.

(post #96473, reply #7 of 11)

I personally like to dado the joints, with the horizontals going "into" the verticals, but that could be habit as much as anything else.


We built a run of cabinets, back in my cabinet shop days, using a dovetailed dado.  Cutter wear versus tolerences for fit & glue conflicts kept that from being a going concern.  Couldn't fault the strength of the connection when it worked.


My experience with biscuits is that they are good for attaching faceframes to in-place built cabinet carcasses.  For shop-built, I still prefer to blind pocket screw the end panels into the face frames.  But, that's likely habit, too (rather than some reasoned, rationated, approach).


Occupational hazard of my occupation not being around (sorry Bubba)
I may not be able to help you Occupational hazard of my occupation not being around (sorry Bubba)

(post #96473, reply #8 of 11)

I've done a lot of sliding dovetails.  Always router cut, no problem with fit.  Would certainly work in this situation, but more than a little over-kill.  I generally used them where I wanted the extreme strength they offer. 


The GC I last ran a cabinet shop for had never seen a biscuit or machine.  He thought it was too easy- cheating.  Compared to dadoing, extremely easy.  Don't think I've ever seen one fail in a bookshelf situation, without racking the whole carcase that is.


PAHS Designer/Builder- Bury it!

PAHS works.  Bury it.

(post #96473, reply #9 of 11)

I've done a lot of sliding dovetails.  Always router cut, no problem with fit.


It's a good joint, no mistake.  Just harder to uniformly execute in a cabinet factory using under-managed help and an under-engineered industrial processes. 


(Your decreeed break-even point is 6-700 doors and 3-350 cabinet carcasses per day.  But you will not program in checking tooling on the machining centers or CNC routers--"wastes labor hours."  That gives you joints that are either too sloppy to be much good, or need hammering in, creating end-of-line QC rejects.  Ergo, use a wider-than-need-be dadu and count on narrow-crown stables toenailed in.  Bonuses for managment all around, yipee!)


Occupational hazard of my occupation not being around (sorry Bubba)
I may not be able to help you Occupational hazard of my occupation not being around (sorry Bubba)

(post #96473, reply #10 of 11)

My last employer (GC building upper end homes) wanted to double production in the same space, to avoid subbing so much out.  Wasn't going to happen, but I spent some time looking into machinery.  Set up a meeting with the principals and went over man-hours currently spent, efficiencies, maintenance, monthly cost for the proposed machinery.  Pointed out that we were already paying for the machine with labor, just didn't have it yet. 


Got asked what it cost.  I repeated the lease terms, including the $50 buyout after 5 yrs.  Wasn't good enough.  "How much does the !*+^&% thing cost?"  OK, $20k.  "Sheeeit, we can't afford that."  After I'd just finished explaining how we were already paying for it.  Oh well.


They aren't in business anymore.  Little chance I would have thought more of your shop.  At least I was able to do pretty much what I wanted.  We always showed a healthy profit and the clients loved us.  I still hear from some of them.  


PAHS Designer/Builder- Bury it!

PAHS works.  Bury it.

(post #96473, reply #11 of 11)

Little chance I would have thought more of your shop.


There's the reason I don't work there anymore.  Management was only successful because there is/was a core group of people who "fit" Dr. Demmings observation about how very few people wake up in the morning thinking "I'm going to do a bad day's work today."  That core group pretty much has to put in extra hours to get the job done.  Every day, and some Saturdays, too.  And they were having to carry the pointy-haired-boss-inspired antiwork, too.


Same sort of management inertia, too.  "That's too fancy for us" should not be in the vocabulary of the VP in charge of purchasing machinery & materials in a $25 million sales cabinet company.  (Well, not if they want to hit $26 . . . )


Occupational hazard of my occupation not being around (sorry Bubba)
I may not be able to help you Occupational hazard of my occupation not being around (sorry Bubba)