Good article on attaching table tops.  What I call "Wood Movement 101", or "You can't stop wood movement but you have to allow for it."   Something not all Asian furniture companies know or care about.

 

I like the opening line: Show me a woodworker who has glued or screwed a solid wood tabletop to its base, and I’ll show you a person who has learned a painful lesson in wood movement.

 

https://www.woodcraft.com/blog_entries/joinery-class-attaching-tabletops?utm_source=SocialOrganic&utm_medium=Social&utm_campaign=Dec22&utm_content=Article&fbclid=IwAR3Srybq2QCXcx9hZOKMbVVrvcWCt6GSKVEQ1FUzdeYh5-rSnTRliZk9GS4

69-JClass-AttachingTops_FINAL.pdf

Thanks for the article!

A trick I learned long ago, from Norm Abram...

 

Involved a series of blocks..

Imagine this at the tops of the leg aprons.....not only does this hold things square, but

By using the drill to mill a slot, you can screw a top down.   The slots allow for the top to expand and contract as it sees fit.   Be sure to add a thin washer under the head of the screw, to help allow the screw to slide.  

 

To drill a slot with a drill:   Drill a hole first..then rock the drill front to back a few times until a slot appears....I usually mark a line to follow, front to back, with a square..

Only 4 ways?   What to do where there are no stretchers just under the top?  What to do when there are no stretchers at all?   How about just gluing a center vertical rib down the centerline of the top matching the grain direction, then hinging legs off that rib?  How about array mortising each leg into the underside of the top?  

Over 40+ year teaching furniture design to creative college kids only rarely did students propose classic 4 legged tables with classic stretchers between them fastened to the hardwood top with the classic techniques shown above.  My personal favorite:  https://4dfurniture.blogspot.com/2016/05/simple-desk-design-tenon-array-joint.html.  It is only stretchers that try to hold the legs in position across the grain of the top that need a sliding connection to accommodate expansion/contraction.  I've had a few students leave a raised dovetail on the two end stretchers, then slide the top halves over those dovetails with a little extra room in the dovetail slot.  Glue the halves to each other once they meet. Don't put any glue on the dovetails.  No need for any corner braces or the hardware shown above.  Dovetail keeps the top flat.  

4D

I believe there is a video out there by Ishitani Furniture, about how he built a Trestle Table.....Might look that up?

Yep.  https://www.youtube.com/watch?v=T5byaGZjpnQ

Although he cut his dovetail slot from one side and had to fill it after inserting the rail.  To avoid that we did the top in two halves.  Mainly as our planer couldn't handle more than 18" of width. Then with a few dowels or later Domino floating tenons to make sure they aligned we would slide each half over the dovetailed rails to glue them together.   

4D

There are multiple ways to skin a cat on table mounting. Can’t say Ive seen much expansion on a top , but I’ve seen plenty of shrinkage…

Edited December 17, 20223 yr by BillyJack

In our college fab lab which doesn't have humidity control shrinking usually surprises the students during the fall semesters as winter approaches as the semester winds up and their project boards begin to shrink.  In the Spring semester expansion happens as winter moves into spring and humidity increases and the students suddenly find their projects showing symptoms such as sliding doors the start to bind, table tops that either buckle up or the frame below started to pop apart if the tops isn't mounted to allow for expansion.

4D

I always seem to be the outlier on this kind of thing.  I've made a dozen or so tables (no really big ones) and I just pocket screw the aprons into the top.  I've never had a problem.  The standard caution should include some insight about what conditions might necessitate the precautions.  Everything I've done still resides in the Phoenix area, which tends to a relatively stable humidity (compared to Florida!), so that makes it simple.  

Yep.  Living in a low humidity area lessens the need to worry about how furniture is put together. That'll be until the 1000 year flood happens and the humidity momentarily peaks at 95%.

I live in Kansas where we see all the seasons.  I lost a job once when a door sign design of mine, which I designed so it would be stable during humidity changes, got changed by the shop that made them. Mainly to lower the cost and reduce the labor needed to make them.  They were installed to add room numbers and patient names to the resident patient rooms of the Menninger Foundation.  Winter came and the furnaces were turned on.  Air dried out, the signs started to shrink in height.  The trapped plastic cover had no where to go so it bowed out until the adhesive keeping in in place failed.  Eventually the plastic covers started popping off the wall.  

Someone had to be sacrificed and since I had designed the signs I earned that honor.  The shop and my manager who had approved the fabrication change were too valuable to mention as responsible. 

I also had a chess board/table I made swell up and break apart when the basement of the townhouse I was living in flooded.  The men all escaped. 

4D