Traditional wood joinery evolved for a reason, and while modern tools and techniques can help render the furniture-making process more consistent and reduce prices, I am seeing more and more newer mass-produced solid wood furniture being poorly built, resulting in an inevitable expiration date. Buyer beware.
Wood moves. It expands and contracts as a function of wood humidity. It does so much more across the grain as with the grain, and at predictable rates. This undeniable truth has been perhaps the greatest single factor influencing how furniture was constructed for thousands of years- until now. It is one of the reasons why doors are normally made of rails, styles, and panels instead of just panels; so they do not seasonally expand or contract out of their frames. It is why bread board ends on harvest tables are pinned and glued only in the centre and then have sliding mortises and tenons on the ends. Run you fingers along where the bread board end meets the solid wood table top and you will notice that it is invariably ever so slightly wider or narrower than the remainder of the table. I can assure you that the day it was sanded, it was flush.
As a furniture maker, I always look at how mass produced furniture is built when I visit retail furniture stores. Over the
past few years I have noticed how pocket screws are becoming increasingly misused in otherwise good quality solid wood furniture, attaching large solid wood panels perpendicularly to adjacent parts. These screws are usually evident from the underside (table aprons and bread board ends to table tops) or the back (bed head and foot boards). Using computerized cutting machinery (CNC), manufacturers are able to very cheaply and precisely cut all the parts within a thousandths of an inch, and then quickly align and screw the composite parts together without a thought of what will happen should wood humidity change once it leaves the factory floor. Maybe this is being driven by consumers’ single minded quest for the lowest price and the pressure from large scale off-shore manufacturers who, because of exceptionally low local labour and material prices, can manufacturer and then ship half way across the world cheaper than a comparable factory with comparable equipment can in North America. Maybe it is supported by our modern building techniques and climate controlled homes that – so long as the power is ON – create for relatively stable humidity environments. But, over time, or should humidity change due to a basement flood, open window, etc, it all may come apart rather dramatically and irreparably.
For example, white ash expands by a rate of 0.00222 inches radially per inch per 1% increase in moisture (averaging quarter and flat sawn values). Now that may seem insignificant, but let us consider a standard 40″ wide solid ash harvest table that is pinned in the centre. If we assume 19″ between the centre and final end screw on the bread board, and 4% increase in humidity (not an uncommon occurrence), that results in 0.00222 x 19″ x 4% = 0.17″, or a little over an 1/8th of an inch, or over 1/4″ over the entire width. If the table top cannot move freely, then it will eventually either rip out the screws or, more likely, as the wood ages and elasticity decreases, that 1/4″ will appear as a crack, or maybe a number of smaller splits in the wood. If we do the same calculations for silver maple, a common North American furniture wood, a version of which is also labelled “brown maple”, the same conditions result in a 0.135″ change, about 1/8″ (9/64″). Less, but still greater than zero. I recently saw a 12′ soft maple (likely red or silver maple) table in a Vaughan, ON furniture store with the table top boards running across the width, and the perpendicular apron was attached by pocket screws along the entire length. Using the above math, a 4% wood humidity change would result in almost an inch of wood movement across the entire length. The table would not survive a hot summer season blackout, I fear, and is unlikely to become an heirloom piece despite the rather hefty price tag.
We all love great deals and low prices, but buyers need to be aware of what they are purchasing. If they wish to invest in something that will last generations, they need to perhaps have a look under or behind the surface.