Replies

1. 
   Lataxe | May 28, 2006 07:22pm | #1

   Josey,

   I should say firstly that my edged panels always start with already-veneered substrates, so I can't offer advice on sticking on your veneer.  Hopefully you already know how to do that.  :-)

   I do quite a few tabletops, shelves, panels and other components in which veneered blockboard or plywood is edged with solid timber, between 2 and 6 cm. wide. Here's my approach, which is mostly using machine tools.  (I'm sure there will be alternative methods):

   I cut the blockboard or plywood rectangles with a TS using a sliding carriage and one of those very pointy TS blades designed to eliminate breakout with veneered boards.  In the US, you might use a cross-cut box of some kind, as the standard mitre gauge will perhaps not have enough capacity or precision.  If the TS is properly set up, you should get perfectly square corners and dead straight edges on the panel.

   The edging is usually ripped off a plank that's initially been planed and thicknessed as required.  (You would say, "jointed and planed). The starting plank is also cut straight and square on the TS.

   To make good glue edges I also pass the solid edges through a drum sander edge-on, just to take out any saw marks and give a good glue surface.  The drum sander is alos good for making the edges exactly the same thickness as the panel, with 0.1mm accuracy.

   You could use a block plane or even hand sand any saw marks off the edges, making sure you don't create any dips or spoil the square profile of the edges.

   You have to hand sand or plane the ply or blockboard edges too, should they have saw marks, as they won't fit in a drum sander.  Again, it's just to take off any saw marks; if you've used that special veneer blade, the sawn edges are often smooth enough and don't need any sanding.

   The solid edging needs to be cut to length so it fits exactly around the inner panel.  I tend to favour a mitre joint at the corners; but you could use a butt joint (with narrow edging especially).   After cutting mitre joints on the TS slightly oversize (ie a tad too long) I trim them down with a Lion hand mitre cutter until they fit exactly around the panel.  You can omit the mitre trimmer if you're confident that your TS will cut reasonably accurate and clean mitres.

   The last stage is to biscuit around the edges, to help line up the edging on the panel; and (if the mitres are large enough) biscuit the mitre joint too.  You only need #0 biscuits with blockboard, as the solid timber edges glue to blockboard very well.  With chipboard (or even ply) I would use #20 biscuits and more of them, as the solid-to-panel edge joints might otherwise be rather weak.

   I glue the whole thing up with a large band clamp around the whole panel-and-edges assembly, with a few bar clamps across the short width to ensure there is no gap left between edging and panel away from the corners, where the band clamp exerts most pressure.

   If the biscuiting has been accurate, it needs only a light sand or planing/scraping to get rid of glue ooze and any small ledges at the joints.

   If there are any gaps between panel and edging, a good way to make it right is to use a router (or hand tool equivalent) to cut a shallow groove for banding/stringing.  The banding hides any gap and provides a nice transition from edging to panel.  You can use commercially made banding, although I like to make simple stuff out of a nicely figured wood, using the drum sander to size it exacly after ripping it off a thin plank.  I prefer quarter inch wide although eighth inch probably looks a bit more elegant.

   Hope this helps.  I can post you a photo, in due course, of a small cherry-veneered blockboard panel, edged with solid cherry and strung with maple, if this would be of any help...?

   One question: is not a 7mm thick top rather flimsy for such a large top?

   Lataxe

    

1. 
   Josey | May 28, 2006 08:14pm | #2

   Hello Lataxe,

   Thank you for your detailed response.

   The method I am following is from discussions with other furniture makers. Most of them use 5mm solid wood edging for this kind of project. basically one edges the plain chip board with about a 2mm wider edging so that when the board goes into the factory that does the veneering using high pressure machines, the 2mm is trimmed accurately and the veneer is applied so that it covers the solid wood edging.

   The reason for such a thin edge is to minimize the movement between the different timber (edge, veneer, & no movement from the chip board).

   My problem is the actual cutting/making of the 7mm solid wood edging. I have managed to slice the 7mm edging - a number of lengths) from a plank of solid wood, however the dilemma (perhaps because of my inexperience with the band saw - if that is the right machine to use) is that the 7mm veneer is not 7mm in all places which now obviously needs to be planed & thicknessed (I think).

   The question in my mind is  - Do I need to invest in a planer thicknesser to complete a project of this nature?

    

1. 
   Lataxe | May 29, 2006 12:16am | #3

   Josey,

   I'm a bit confused about the orientation and thickness of the edging for the chipboard now.  Is the chipboard 5.5cm thick and the edging 5.5 cm wide but 7mm thick?

   I doubt, also, if differential expansion of solid wood laid along the grain against chipboard would be a problem except in fairly extreme climates (which you might have of course).

    

   Anyway, in respect of your edge strips, the first thing you might consider (for future projects) is to tune up your bandsaw so that it cuts more evenly.  This FWW site has good advice on bandsaw tune ups and use - find it via the index from the home page.

   If your 7mm thick strips were more even from your saw, you could just sand or plane them to size.  However, if you want to thickness unevenly cut ones without practicing hand tool skills on a few dozen first, a planer of drum sander would be a lot easier, I can tell you from experience.

   A planer is more versatile for thicknessing all sizes of rough planks, including 7mm thick ones.  You would still need to sand off any planer marks to get a good glue surface. Some planers can be set more accurately, for thickness, than others.  Mine can manage about +/- 0.2 mm but some are only +/- 1mm or worse.

   If you want superfine accuracy and finish on thin, small pieces (like your 7mm edge strips) a drum sander does a better job.  The drum-sanded pieces are also ready to stick on straight out the machine.

   Of course, I am spoilt and have both machines. 

   If you had to choose one, the planer should be first choice, though.  It's more versatile. However, you could do without either machine, in respect of the edge strips, if you could just get a better cut from your bandsaw - although planers and drum sanders do make life easier.  How much money have you got for WW and how much WW will you be doing - this is the equation to balance.

   Lataxe

1. 
   Josey | May 29, 2006 10:55pm | #4

   Hi Lataxe

   The Desk top  is 1.6 metre in length and 1.0 metre wide with a thickness  of 5 cm wide - (from top surface to bottom surface of top). There are two side pieces which efectively form the legs but they are as wide (1m ) as the table top. The desk when completed would make the shape of the letter "n" or upside down "u" except with no round corners. 

   I have taken a 16millimetre and a 32 millimetre chip board and have glued them face to face to make a 48mm thick plain chip board. I have cut this board into 3 pieces to make up the desk top and the two side pieces (legs). The company that does the veneering suggested a 5mm to 7mm thick edging around these cut pieces which would then be veneered all the way on the flat surfaces right onto the 7mm edging. When this veneering is completed, then the board would look like solid wood.

   Now here is the good news. I took your advice and went out and bought a planer which I have already used and have perfect edging that is now about 5mm thick! Thank you for the advice as I now have machine that I can use to make light work of all the floor boards I have saved to use for a special project.

   Now the next step is to glue the edging on the sides of the  48mm chipboard. I plan to do this by applying the glue and using strips of masking tape along the length  to hold the edging until dry.

   The other puzzle I have is how to reinforce the joint where the verticle board (legs) meet the desk top. I have someone suggesting that I would have to use two metal plates from underneath on either side to secure this joint. I was planning to use a Festool Domino machine to do the joint but was advised that this would not be enough.

   Any suggestions on this?

   Thanks for all the help thus far, much appreciated.

   Best wishes

   Josey

1. 
   Lataxe | May 29, 2006 11:22pm | #5

   Josey,

   All is now clear, although your desk is going to be a Good Weight, I imagine!

   I doubt if there is any jointing technique for the legs-to top joint "as-is" that will be strong enough to resist the racking forces that could potentially be applied to the desk.  I fear you will have to reinforce the leg-to-top joints with some more beef. 

   The suggested metal brackets will possibly be the best solution in terms of strength-versus-size; that is, they will be the least obstrusive solution.

   One other approach might be to put larger wooden brackets, or even a thick batten, into the internal right angles between legs and top.  You could then put a form of solid wood facing on the front-facing edges of the desk designed to obscure this reinforcing at the corners.  You could also put a bendy-ply skin over the brackets or batten, veneered to match the rest of the desk.

   Another approach might be to put a stretcher or two of some kind between the legs, but towards the back face of the desk, with one strecher near floor level and the other higher up, or even up on the back edge of the top. 

   These strengthening solutions might not be in keeping with your design needs, though.  It sounds like you're after a simple modern style....?

   Incidentally, you'll need to make sure the glue used to stick the solid wood lipping to the chip board is of the right type.  Epoxy would be toughest but a normal glue like PVA might be OK.  I've never used chipboard myself, I confess. 

   Myself, I'd put a "belt" on the glue "braces" by pinning the lipping with 18 or 23 gauge pins about every 8 inches.  You might have to hide their heads with a bit of beaumontage, hard wax or dust/glue mix of the right colour.

   Hope these thoughts help.

   Lataxe

2. 
   Josey | May 30, 2006 10:43pm | #6

   Hi Lataxe,

   You are 100% correct, this desk is going to need at least 4 people to move it. My problem is that I have to match existing furniture.

   The wife suggested the thick batten, but the client would not want this. I guess I will have to stick to the metal brackets. My other concern is to transport this monster once it is completed. I was contemplating leaving the legs unassembled and only doing the assembly at the clients offices. This would mean screwing the brackets on during assembly. I feel this would also be good for the client if he ever wanted to move the desk as well.

   I have gone for the masking tape option and it seems to be working reasonably well with gluing the edging. Tomorrow the edged items go to the veneering factory and if they are happy with it I should get it back before the weekend to begin the attachment procedure and finishing. I am going to keep you informed and with post some pics for you to see.

   Thank you so much for your advice.

   Best of health to you,

   Josey

3. 
   Lataxe | May 31, 2006 12:41am | #7

   Josey,

   You're right to think about making your desk knock-down I think, given its likely weight.  But this probably means that the join of the legs to top will have to be even stronger.  Those metal plates might be the only thing that keeps it all together. 

   On the other hand, if the sections are 5cm thick that does provide plenty of meat for inserting super-strong reinforcement of some sort. 

   One solution might be to use an internal spline of metal down into the leg sections, in addition to right angle metal brackets in the corners.  You could route a deep, long stopped mortise of, say, 12mm wide and 5cm deep in the leg tops; then insert an aluminium plate to stick up into a matching-but shallower mortise routed in the underside of the top.

   I'd love to see a pic of the finished article.  I've neve rmade a thoroughly modern piece as I haven't the artistic ability to know what will be an elegant and timeless design and what will be a merely fashionable item that will look ridiculous in 2 years.

   I suspect that the answer is "simplicy of form", "beautiful surface" and "natural  proportions", which sounds like your desk.

   EDIT: Another thought: could you use bed bolts to join the legs to top?  They're very strong and Lee Valley make some for workbenches that are as beefy as billy bull without his pyjamas on.

   The bolt holes would need to be covered in a way to keep the clean look, I suppose.

   Lataxe

   Edited 5/31/2006 2:10 pm ET by Lataxe