Advice - DIY Desks

[Mike Dodd]

I'm in the process of replacing one set of DIY'd desks (wall-to-wall computer desks) with a new, "better" pair.

I've previously seen (and was tempted by) pre-made oak desk-tops, formed by glueing several PSE boards together with a double row of biscuits. This seemed like a good idea, so I trotted down to the local timber merchants to price up oak, and other hardwoods, in order to do the same (cost of delivery of the pre-mades being the major factor, here, plus, I've fancied dabbling with a bit of woodwork for a while).

Now, whilst chatting to the guy at the timberyard, who suggested he used to do "a lot of this" in a previous life, he suggested that he would never use biscuits because... (at this point, his quiet nature, the sound of the timber yard, my age-induced deafness and nack of interrupting at inopportune times) meant I missed the whole explanation, but it centred around some argument of the strength of the glued joint being so much more than the strength of the wood...

Can anyone explain in a more clear way (to me) the rationale behind this?

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:-

########## ========= ####### +++++ ====== ########## =========

# : 1st board = : 2nd board

• : fillet

Which would require me to knock up a jig for doing this (or borrowing my dad's table-saw.... there's an idea)

...or... to use a rebate joint, glued...

############## ========= ############## ========= ####### ================= ####### =================

Which I could do easily enough with a router, I'm sure.

Now, the false tongue - I can understand, although is it not simply a "very long biscuit"?, so why's this preferable to a double-row of biscuits?

The rebate joint just... I dunno... doesn't feel right - it relies completely on the strength of the glue bond to provide the strong work-surface needed for a desk-top.

Any comments? (would be gratefully received - it's a lot of expensive wood that I'm about to start molesting, and this is my first experiment beyond pine/soft-wood)

Mike

[Ian]

Yes, what is it you are asking? No need for a lecture, speech, extracts of conversations with yourself or sentences interrupted by brackets.

Do you just want to know how to join pieces of wood?

[Mike Dodd]

Well... yes.

Although I explained my initial idea - to use biscuits, and questioned why that might be considered a bad idea.

Then presented one suggestion, which appeared to be an expansion of the first idea (false/loose tongue) - and questioned why that was considered better.

Then a third, easier suggestion, which doesn't sound right to me, but if others have had successful experience of this, then it's a good option.

Sorry for presenting too much info.

[Steve Firth]

Why not troll elsewhere, you arsewipe?

[Steve Firth]

Don't apologise to the Beale arsewipe. He's a known troll from other newsgroups and can't tell arse from elbow.

I'm not a great fan of glued block worktops. I have used them and I have made them in the past. But they're a lot of fiddling about to come up with something that (IMO) doesn't look that good and doesn't work well either. In general they're cheaper to buy than to make, Ikea offer suitable tops at a reasonable price. They're useless for the purpose that Ikea sell them for - kitchen worktops - because the glue they use isn't fully waterproof, but they do make decent (ish) desktops.

If making them yourself then IMO it's fairly academic whether you join them by simply glueing PSE, biscuit jointed, dowelled, or joined with a fillet or T&G as you suggest or think the bloke at the yard suggested.

It's possible to buy cutters for spindle moulders to create the tongue and groove or to machine a comb edge to increase the glued surface, a small spindle moulder will cost about £100.

A good quality oak worktop 3m x 950mm x 38mm will cost you about £250.

[Roger Mills]

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.

[stuart noble]

A hardwood tongue is cut cross grain, so you need a series of them for a long joint. Using a sawbench the ends of the tongue would be visible

[Dave Plowman (News)]

Look round the sheds etc for some end of range engineered solid oak flooring. Clamp and glue that together and to a MDF etc base. Edge with the same stuff planed to fit. You should be able to get it for about 15 quid a sq mtr. It probably wouldn't stand getting soaked in water - but will be fine for your job.

[The Natural Philosopher]

rebating is good BUT you meed to screw from underneath otherwise differential movement will split the joint apart.

The key to glue joins is to always have them in shear. That way they are strong. They are NOT strong in tension, and will often pull the top layer off the wood or fail in te glue itself.

Also, even a glued mortice and tenon join should not be relied upon: again differential expansion in changing humidity can split these apart eventually.

I have to say that when making *functional* stuff out of hardwoods, I tend to screw the ruddy things together hard.

For a simple table or desktop I'd probably set a router up to T & G the boards, and then make very soliid cross braces to go underneath. Or buy the block kitchen unit tops.

Or use veneered MDF or ply. Its actually very realistic if combined with real wood pieces.

[Tim S]

Mike Dodd coughed up some electrons that declared:

It's not very DIY but I got a couple of these:

they have solid wood tops, 25mm thick, I had the choice to mount the tops off-centre front-back giving a nice overhang on the front (less squidging of the vitals and somewhere to clamp stuff, eg a vice).

Trimmed one table down by 4cm lengthwise and a quick sand and a wipe of danish oil on the cut surface and you can't even tell it wasn't made that way. Both tables end to end fit my "lab" perfectly and are fantastic for computer and electronics related wibblings.

The frame is very solid - halfway good enough for light (ok very light) workshop use.

Just a lateral thought...

Cheers

Tim

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Ian" saying something like:

As if you'd know how.

[The Medway Handyman]

Not a good idea. The natural wood will expand/contract at a different rate to the MDF and cause the surface to bow badly.

BTDTGTTS. Not something I've ever done, but saw a whole bedroom full of home made wardrobe doors made like that. They had all bowed badly & beyond redemption.

[The Medway Handyman]

Biscuit joining is the modern version of the false tongue joint. Easier, faster & safer to cut. You can use a router but a biscuit joiner is far better. Even a cheap one works OK

've never, ever heard of, or had any problems with biscuit joins.

This bloke in the timber yard sounds like he was stuck in a 1950's time warp. His name wasn't Tanner OP was it?

[Mike Dodd]

The one advantage that I can see with a false tongue, over biscuits, is a larger surface area for the glue.

That's good, the missus bought me a cheap one many xmas's ago. Maybe time to dust off the box.

In fairness to the guy, he did sound pretty clued-up, and helpful. He also offered that if I was to bring my router in, that he'd show me how to set-up and keep a watchful eye over the proceedings. In honesty, though, if I'm going to f*k up a load of wood, I'd rather do it in the privacy of my own home. When I go to collect the wood, I may just bend his ear a bit more.

[Mike Dodd]

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 c*ck it up, I can hopefully learn from the experience.

Regards,

Mike

[The Medway Handyman]

Biscuits leave more of the edge timber available for glue. The idea is they hold the boards 'level' while the glue dries.

[stuart noble]

Not difficult at all, and hardly dangerous with the blade set so low. A router does have the advantage that you can stop the groove though

[Roger Mills]

Yes, I know it *can* be done - and I've done it myself - but a router is far safer and, as you say, can be stopped.

I don't think that we'd ought to be *recommending* people to run table saws with the guards removed!

[dennis]

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Have you looked at

[Dave Plowman (News)]

I've done it with great success. Of course if the conditions in the area are strange - high humidity etc - anything can happen.