Roger Mills wrote:
In an earlier contribution to this discussion,
Mike Dodd wrote:

As an alternative approach, he suggested (I think the phrase was...) a
false tongue using a hard-wood fillet (using a circular/table saw to
cut a groove along each edge of the boards, and inserting (and presumably
glueing) a hard-wood insert to form the tongue.... ASCII art alert:-


I've no experience of biscuit joints - but the 'false tongue' approach would
work ok.

Don't use a table saw to cut the grooves though - use a router. It's pretty
dangerous using a table saw because you'd have to remove the guard - and not
very accurate because it's difficult to handle wooden planks edgeways on.

Thanks to all of the (constructive) replies, so far,

I'm favouring the loose/false tongue approach at this time, using a
router to run up/down each board. I *think* this will be stronger than
biscuits, and not significantly harder to achieve. One book that I have
that describes this for joining manufactured boards recommends 6mm ply
for the tongue, as the ply structure is stronger in bending than a
long-grained section of hardwood (answering, to some degree, Stuart Noble).

Answering Dave Plowman - I've considered several variations to your
theme, up to sourcing a load of veneer (that avenue quickly got
complicated), but the desk is not purely one of function, but also the
pleasure of hitting bits of wood wi' hammer. Despite the low cost, and
stability, and eminent suitability of MDF, I have a personal hatred of
the stuff.

That answers, Tim S, also - in fact, a (different) local timber yard
offers oak worktops at £200 for 3m lengths. There's a slight problem
that I need a total of 3.6m (although formed as 2x 1.8m desktops -
his&hers), but as said in the original post - I fancy dabbling with a
bit of woodwork at the same time (besides, the router hasn't paid for
itself, yet, since its only real use for fitting the kitchen worktops -
jointing, and sink/hob cutouts).

Answering Steve Firth - the timber is to be supplied cut at 2m lengths
(for 1.8m finish - I like having a bit to play with), so it won't be
block-work, but single-staves (is that the phrase - for running the
length of the desk?). Regarding the spindle-moulder, would love to have
one, but simply don't have the space for it. I have, however, been
pondering over similar cutters in Screwfix for the router.

Answering Natural Philosopher - I agree about the cross-braces - it's
how I've done the existing desk-tops, and would provide a key into the
existing support-strips on the walls. Veneered MDF/ply - I can source
veneered ply for around £60/sheet, but the timber is coming in not
*substantially* more than that, and I like having the option to form
edges easily (e.g. bull-nose the working edge and cable holes, and maybe
sweep one edge of the desk into an arc) - the existing desktops are made
this way from veneered block-board, and the faffing about with edging
mouldings is part of the reason for replacing them. I have seen
info/movies online for the use of real pieces to edge shaped
veneered/manufactured boards, and until yesterday this was the approach
I was favouring, however, the low price differential from real timber vs
board (~£80/desk vs £60) makes me more inclined to try the real-wood
approach.


Anyhow, if I cock it up, I can hopefully learn from the experience.

Regards,

Mike