Leadwood Desk
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custard
Established Member
phil.p":1cj4tlh9 said:
You're right Phil, but that's only part of the reason.
IMO with any waney edged, slab top piece it's important that it's the top that's the "hero" of the overall design. If other components start competing for your attention then that can't be good. I've made quite a few of these and the base/legs have ranged from Asian influenced floating tops to industrial trestles to traditional aprons and tapered legs, but in all cases I've tried to strike that balance of something that compliments the top without in any way competing with it. This is the last one I made, a Bubinga top with scorched and iron stained Oak legs.
I'd previously done a few of these with iron stained Oak legs to get that jet black colour, but this was the first time I'd added scorching to bring some texture into the equation. I was worried that it might steal some limelight away from the top, but it seemed to work out okay. I'll be doing this again in 2017 with a big and dramatically figured Elm slab, I might push things a bit further on that and have scorched, iron stained Oak legs but add a bit of splay. Maybe that'll end up being a bridge too far, difficult to say until it's actually made and you've lived with it in the workshop for a bit.
The second reason for choosing Beech was that when oiled it's a pretty close colour and texture match to the Leadwood sap, so it's nice to pick that up and echo it elsewhere in the design.
And the third reason for choosing Beech may sound a bit arty farty but here goes, the Leadwood itself seems to have quite a detached and clinical personality, like Walnut or African Blackwood it's at the cool end of the timber colour spectrum, and it's granite hardness and tight grain seemed to add to that air of precision and aloofness. Consequently I've modelled the base on a draughtsman's or architect's work table, they always seem to have splayed front legs and be made from Beech, and that also seems to key in to that idea of detached, cool, precision.
Hey, maybe I'm talking through my backside, but that's what led me to choose Beech!
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custard
Established Member
Checked how the roughly dimensioned Beech components had behaved themselves after resting for a few days and they were all bang on.
So time to take them all down to finished dimensions plus a 0.5mm allowance in width and thickness for final hand planing and sanding.
It's always important to have your components square and true. But with Domino joinery it's doubly important. On traditional mortice and tenon joinery you often end up fitting each joint individually, with a bit of scribing and tinkering to get the fit you want. Tight shoulders all around for first class work, tight shoulders on all show faces and maybe an occasional minute gap hidden round the back for second class work. But with Dominos you tend not to fit each joint individually, you could, but for some reason most makers (myself included) tend to go straight to glue up. I guess that's how you get the time savings that motivated you to buy a Domino in the first place!
But here's the rub, to get away with that, all the components have to be absolutely square and true. Because you reference directly from the components in Domino joinery, it's therefore the accuracy of your initial machining that will determine the accuracy of the finished piece.
I have met a couple of new Domino users who were a bit disappointed with the results they were getting, one of the major explanations is if their equipment or technique wasn't capable of producing really precise components in the first place. So your planer knives, planer fence, and cross cut fence all have to be absolutely dead on accurate. Furthermore, as is the case with all cabinet making, you then have to keep checking throughout the build for square, flatness and general truth in the components. Wood may move, so you have to be able to identify when that happens and immediately correct it with a few strokes of a hand plane.
So time to take them all down to finished dimensions plus a 0.5mm allowance in width and thickness for final hand planing and sanding.
It's always important to have your components square and true. But with Domino joinery it's doubly important. On traditional mortice and tenon joinery you often end up fitting each joint individually, with a bit of scribing and tinkering to get the fit you want. Tight shoulders all around for first class work, tight shoulders on all show faces and maybe an occasional minute gap hidden round the back for second class work. But with Dominos you tend not to fit each joint individually, you could, but for some reason most makers (myself included) tend to go straight to glue up. I guess that's how you get the time savings that motivated you to buy a Domino in the first place!
But here's the rub, to get away with that, all the components have to be absolutely square and true. Because you reference directly from the components in Domino joinery, it's therefore the accuracy of your initial machining that will determine the accuracy of the finished piece.
I have met a couple of new Domino users who were a bit disappointed with the results they were getting, one of the major explanations is if their equipment or technique wasn't capable of producing really precise components in the first place. So your planer knives, planer fence, and cross cut fence all have to be absolutely dead on accurate. Furthermore, as is the case with all cabinet making, you then have to keep checking throughout the build for square, flatness and general truth in the components. Wood may move, so you have to be able to identify when that happens and immediately correct it with a few strokes of a hand plane.
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I am going to buy a piece of Walnut to make a waney edged occasional table and the finished surface dimensions will be 600 * 1200 mm what thickness would you suggest. I haven't decided on the wood for the legs but the iron stained Oak sounds interesting, how is it done?
Really good to see a professional mapping out his work and showing how it's done, a big thank you =D>
Really good to see a professional mapping out his work and showing how it's done, a big thank you =D>
custard
Established Member
PeteHB":2hwwlunq said:
Structurally you'd actually be fine with any thickness over about 15mm, someone could stand on that without it breaking. But to draw attention to the wane and fit with that "live edge" aesthetic you really need 40mm+. However, once you go over about 50 or 60mm drying becomes a bit hit or miss, so on really thick pieces you either have to be dead sure they've been thoroughly air dried or properly kilned, or you have to leave them in stick (in an environment similar to it's final destination) for months and months, maybe a year or more. So I'd suggest you look out for something in the range 40-50mm.
If you search this forum you'll find more information on how to iron stain Oak or indeed any timber. The key things that are rarely mentioned on internet recipes are firstly to load the surface with additional tannin (even Oak and Chestnut rarely have sufficient surface tannin to guarantee a uniform jet black), and secondly to add a drop of washing up liquid to break surface tension and ensure both the tannin and the iron solution get deep into the pores.
Good luck!
custard
Established Member
With the components all machined it's time to mark out for the joinery. But first it makes sense to check that no mistakes were made during machining. The rod comes in handy for this as you can lay out all the components directly on the plan (which is where you got the cutting list dimensions from in the first place) and check for accuracy. This provides a far better guarantee than just running a tape measure over the wood.
This approach never seems to get enough emphasis in the books or on Youtube videos, this need for checking after each process. You never stop checking with furniture making, the calibration of machinery, the accuracy of components, the precision of joinery. Everyone's heard the phrase "measure twice, cut once", but what's not so widely appreciated is the mindset which this expression comes from, where you never move on from any process until you've personally checked it and verified the results. That makes it all sound a bit paranoid and stressful, it's not really like that, but when I watch really accomplished craftsmen and women at work there's no doubt that they're quietly checking after each stage.
Next job is to mark up for the Domino joinery.
It's worth saying a couple of words about the whole subject of marking up, as again it's just not covered that well in the books (actually, I think David Charlesworth does go into it in quite a bit of detail). A lot of mistakes happen when your joinery marking is ambivalent or unclear, so early on in your woodworking career you need to develop a series of shorthand marks that gives you all the information you need.
Personally I always start by marking the tops of legs, starting from the back left and working around clockwise, "A", "B", "C", and "D". Now, this is a terrible system so I'd recommend you come up with something better! If you draw an "A" with a rounded top then it's easy to confuse it with a "D", and all those letters apart from an "A" are easy to get disorientated if you look at them from any angle apart from straight on. I only stick with this because over forty years I've ironed out it's inherent problems. If you're starting from fresh then I'd recommend you invent your own, superior system and stick with it. The time will come, when you're tapering the inside faces of legs or laying out mortices, when a notational system will save your bacon!
Dominos require yet more marking out symbols. If you're using multiple dominos in a single joint the chances are you'll have some that are on the "tight" setting and some on the "sloppy" setting, so i use a squiggly line to signify "sloppy" and a circle to signify "tight".
Here's a couple of examples on this job,
If there's any doubt about the orientation of the mortice then I also add a red line with a lumber crayon to make it crystal clear which way around that domino mortice should be cut.
Once again, the rod is very useful for laying out your joinery markings, it gives you an absolute reference that you can use to check that all your marks are in the right place before you spin up the domino machine (or reach for a chisel).
I don't recommend buying loads of superfluous layout tools, but for Domino joinery where you frequently have to carry a line around a corner then I find a saddle square speeds up the job and removes one possible source of error,
This approach never seems to get enough emphasis in the books or on Youtube videos, this need for checking after each process. You never stop checking with furniture making, the calibration of machinery, the accuracy of components, the precision of joinery. Everyone's heard the phrase "measure twice, cut once", but what's not so widely appreciated is the mindset which this expression comes from, where you never move on from any process until you've personally checked it and verified the results. That makes it all sound a bit paranoid and stressful, it's not really like that, but when I watch really accomplished craftsmen and women at work there's no doubt that they're quietly checking after each stage.
Next job is to mark up for the Domino joinery.
It's worth saying a couple of words about the whole subject of marking up, as again it's just not covered that well in the books (actually, I think David Charlesworth does go into it in quite a bit of detail). A lot of mistakes happen when your joinery marking is ambivalent or unclear, so early on in your woodworking career you need to develop a series of shorthand marks that gives you all the information you need.
Personally I always start by marking the tops of legs, starting from the back left and working around clockwise, "A", "B", "C", and "D". Now, this is a terrible system so I'd recommend you come up with something better! If you draw an "A" with a rounded top then it's easy to confuse it with a "D", and all those letters apart from an "A" are easy to get disorientated if you look at them from any angle apart from straight on. I only stick with this because over forty years I've ironed out it's inherent problems. If you're starting from fresh then I'd recommend you invent your own, superior system and stick with it. The time will come, when you're tapering the inside faces of legs or laying out mortices, when a notational system will save your bacon!
Dominos require yet more marking out symbols. If you're using multiple dominos in a single joint the chances are you'll have some that are on the "tight" setting and some on the "sloppy" setting, so i use a squiggly line to signify "sloppy" and a circle to signify "tight".
Here's a couple of examples on this job,
If there's any doubt about the orientation of the mortice then I also add a red line with a lumber crayon to make it crystal clear which way around that domino mortice should be cut.
Once again, the rod is very useful for laying out your joinery markings, it gives you an absolute reference that you can use to check that all your marks are in the right place before you spin up the domino machine (or reach for a chisel).
I don't recommend buying loads of superfluous layout tools, but for Domino joinery where you frequently have to carry a line around a corner then I find a saddle square speeds up the job and removes one possible source of error,
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Bodgers
Established Member
That is one incredible piece of wood. The surface you have on that is super too.
Are we allowed to know what kind of money is needed to get a board like that?
Sent from my MI 3W using Tapatalk
Are we allowed to know what kind of money is needed to get a board like that?
Sent from my MI 3W using Tapatalk
custard
Established Member
Bodgers":12jy9f8r said:
The Leadwood slab was about £600, maybe a bit less, I'd have to check. The Bubinga slab I posted earlier with the incredible waterfall rippled figure was about £800, but that was a mighty board that needed several feet trimming off the length. You can get dining table sized Elm, Sycamore and Oak slabs for anywhere from £100 to £400, Walnut at about £300 to £500, and at the other end of the scale I found some similarly sized slabs of flawless Nicaraguan Cocobolo that were an absolute steal at £3,000 given that they'd fetch three or four times that price if cut down and sold into the luthier trade. Basically there's good quality material at pretty much every price point if you put the time into tracking it down!
Random Orbital Bob
Established Member
Nice to see a professional furniture maker making furniture rather than teaching it! This is a lovely thread Custard, especially at Christmas for some reason 
custard
Established Member
With all the joinery marked up next job is to cut the domino mortices. Actually it's worth pointing out that in reality I've just done that and I'm now having a tea break! 30 mortices in 16 joints in under an hour, that's how a domino pays for itself and that's why it's worth putting the time into accurate procedures, so you can achieve those efficiencies with no errors. To hit the time scale on this job (which admittedly is very, very simple) it all has to be glued up and have the first coat of finish tonight before I finish.
Anyhow, I'm getting ahead of myself. It's worth mentioning the need to calibrate your Domino.
There's an etched line on the base plate of both the 500 and 700 machines that is pre-calibrated at the factory, you can bet your life that that line will accurately indicate the precise centre of the mortice. Unfortunately you rarely use that line, you're much more likely to use the centre line in the perspex window which will not have been calibrated when you get the machine. This is the perspex gauge line I'm talking about,
Actually it seems the factory set up is a bit more accurate on the 700 than on the 500 (I guess Festool have changed their assembly method for the larger machine) but it's still not guaranteed accurate, you have to do that yourself. There's plenty of advice on the web so I won't go through it here, but it's something that absolutely needs to be done along with calibrating the fold out paddles or the pins on the early 500 machines. Calibration of all these components is down to the user and in my experience you'll get a noticeable improvement in accuracy by doing it.
How accurate should it all be? It's difficult to quantify but the test I apply is that any flush joint should be seamless to the touch. Given that a step of 0.1mm (about four thou) is easily distinguishable to the touch, and even a one thou step is noticeable if perhaps not particularly objectionable, then you could reasonably conclude that even with the best calibrated machine and the most meticulous operational procedures you're going to be hard pressed to make every joint acceptable straight off the tool. That's pretty much been my experience, for first class work there'll still be some small remedial action required. The challenge is to make that remedial action as minimal as possible, just a swipe or two with a plane or a sanding block. And I'll also talk later about another trick than can remove the need for even these small remedial steps in flush joinery.
The first thing I try and do to crank up accuracy and precision is to use the sole plate flat against a known flat surface wherever possible. It's not that I never use the fold down fence, but I rarely use it. But to use a domino in this fashion requires shimming either the machine or the workpiece. To be honest I'm still searching for the perfect shim material. The ideal shim would be cheap, consistently and uniformly thick (which rules out plywood for example), could be easily cut with your existing tooling (without leaving rippled edges that would throw out precision), would be easily distinguishable between different thicknesses so you don't get mixed up, and would be available in 0.5mm thicks. I've ended up with a mix of MDF and different coloured hard plastic sheeting.
If anyone has got any better shim material suggestions then please share them.
Anyhow, tea break over so it's back to work. Just one additional photo, illustrating how easy it would be to confuse a pencil or scribe line with the natural grain markings of timber,
Anyhow, I'm getting ahead of myself. It's worth mentioning the need to calibrate your Domino.
There's an etched line on the base plate of both the 500 and 700 machines that is pre-calibrated at the factory, you can bet your life that that line will accurately indicate the precise centre of the mortice. Unfortunately you rarely use that line, you're much more likely to use the centre line in the perspex window which will not have been calibrated when you get the machine. This is the perspex gauge line I'm talking about,
Actually it seems the factory set up is a bit more accurate on the 700 than on the 500 (I guess Festool have changed their assembly method for the larger machine) but it's still not guaranteed accurate, you have to do that yourself. There's plenty of advice on the web so I won't go through it here, but it's something that absolutely needs to be done along with calibrating the fold out paddles or the pins on the early 500 machines. Calibration of all these components is down to the user and in my experience you'll get a noticeable improvement in accuracy by doing it.
How accurate should it all be? It's difficult to quantify but the test I apply is that any flush joint should be seamless to the touch. Given that a step of 0.1mm (about four thou) is easily distinguishable to the touch, and even a one thou step is noticeable if perhaps not particularly objectionable, then you could reasonably conclude that even with the best calibrated machine and the most meticulous operational procedures you're going to be hard pressed to make every joint acceptable straight off the tool. That's pretty much been my experience, for first class work there'll still be some small remedial action required. The challenge is to make that remedial action as minimal as possible, just a swipe or two with a plane or a sanding block. And I'll also talk later about another trick than can remove the need for even these small remedial steps in flush joinery.
The first thing I try and do to crank up accuracy and precision is to use the sole plate flat against a known flat surface wherever possible. It's not that I never use the fold down fence, but I rarely use it. But to use a domino in this fashion requires shimming either the machine or the workpiece. To be honest I'm still searching for the perfect shim material. The ideal shim would be cheap, consistently and uniformly thick (which rules out plywood for example), could be easily cut with your existing tooling (without leaving rippled edges that would throw out precision), would be easily distinguishable between different thicknesses so you don't get mixed up, and would be available in 0.5mm thicks. I've ended up with a mix of MDF and different coloured hard plastic sheeting.
If anyone has got any better shim material suggestions then please share them.
Anyhow, tea break over so it's back to work. Just one additional photo, illustrating how easy it would be to confuse a pencil or scribe line with the natural grain markings of timber,
Attachments
iNewbie
Established Member
custard":3mn2rpc8 said:
I wonder if offcuts of FR4, etc, Epoxy circuit board material would work.
http://www.gaatech.com/FR4-G10-GRP-Epox ... s/1818.htm
Just a thought.
AJB Temple
Finely figured
I might have to look into one of these domino tools!
custard
Established Member
AJB Temple":1m7fxccc said:
I hope I'm not sounding like a fanboy, Domino machine's are great, but they're not a silver bullet solution to all your jointing needs. They won't do haunches, they won't do those twin tusk tenons that are needed all the time in solid wood cabinetry, they're very limited in terms of mortice width, they need calibrating, if you want a rot proof tenon for exterior use you either have to make your own or buy Festool Sipo stock in long lengths, they struggle on angled sections unless you joint perpendicular to the surface, etc, etc.
But if you can design a project to fit within the domino's limitations, and you've sorted out how to work with the machine, then they're incredibly fast!
custard
Established Member
With all the joinery complete it's time to clean off all the pencil marks, workshop grime and machining marks. You can do that with a plane or by sanding. I base the decision on how the project will eventually be finished. If it's an oil finish then I'll use either, but if it's a thin film finish like shellac or varnish or lacquer then I'll only sand. The reason is that planing (or scraping) leaves small scallops and ridges in the surface, not visible to the eye but easily detectable by touch. The risk is that you can cut through a thin film finish on one of these ridges by subsequent sanding or burnishing or nib removal (or that the client will eventually rub through by polishing) and expose the bare wood beneath.
This job will be finished with Osmo so rather than working through three or four grades of sanding grit I'll just plane it clean with a finely set smoothing plane in half the time.
Not really relevant to domino joinery but it's worth pointing out that a bog standard Record with its original thin iron does a perfectly adequate job. If you're a shaving-o-holic these are the shavings you can get,
About 40mm wide, tapering out to nothing at the edges, no tear out, and the original iron will retain an edge long enough to do this job five or six times over at least. I'm not sure there's anything else I could ask from a smoothing plane?
Before gluing up I always do a dry assembly to check there are no problems.
Everything looks good. So there's just one job left to do before beginning the glue up, which is remove the arrises and round over all the edges.
It's surprising how a client's evaluation of furniture usually includes the tactile aspects, and it's surprising how High Street furniture (even very expensive High Street furniture) does a poor job on this. Every single part of my furniture will feel smooth and friendly, even the parts you wouldn't think of. I ease the edges of butt hinges and brass door catches, interior shelves, tops of drawer sides, any part in fact that it's remotely conceivable that someone might ever touch.
But with flush joinery that brings a problem, do you run rounds right along the edges of legs or stiles, when aprons and rails will be flush jointed into them?
The answer is yes you do, and furthermore you make use of a little known device that's known in some workshops as the bumcheek moulding! Basically it's whenever a round or bead is butted up against another round or bead. Here's what it looks like,
So I've fitted a 2mm or 2.5mm round over bit in a router table (Wealdens new "arris bits" are magic) and run all the long edges of every component through,
You could set up a cross cut slide on the router table to make the corresponding cut on the ends of the stretchers/stiles, but I prefer to just form them by hand with some 180 grit on a hard sanding pad (if you use a soft pad you'll dub over the corners which looks horrible).
The bumcheek moulding removes at a stroke the problem of making flush joinery perfectly "flush", as long as you're within 0.1mm or even 0.2mm the joint feels flush even if it isn't. This is key to taking full benefit from the speed potential that a domino machine affords. The other advantage is it adds a neat little shadow line which makes your joinery look really professional. I use it all the time in all sorts of applications,
Here's a Shaker style cabinet I made last month, you can just see how the face frame stile is jointed to the cabinet's side using this device. Thoroughly recommended!
This job will be finished with Osmo so rather than working through three or four grades of sanding grit I'll just plane it clean with a finely set smoothing plane in half the time.
Not really relevant to domino joinery but it's worth pointing out that a bog standard Record with its original thin iron does a perfectly adequate job. If you're a shaving-o-holic these are the shavings you can get,
About 40mm wide, tapering out to nothing at the edges, no tear out, and the original iron will retain an edge long enough to do this job five or six times over at least. I'm not sure there's anything else I could ask from a smoothing plane?
Before gluing up I always do a dry assembly to check there are no problems.
Everything looks good. So there's just one job left to do before beginning the glue up, which is remove the arrises and round over all the edges.
It's surprising how a client's evaluation of furniture usually includes the tactile aspects, and it's surprising how High Street furniture (even very expensive High Street furniture) does a poor job on this. Every single part of my furniture will feel smooth and friendly, even the parts you wouldn't think of. I ease the edges of butt hinges and brass door catches, interior shelves, tops of drawer sides, any part in fact that it's remotely conceivable that someone might ever touch.
But with flush joinery that brings a problem, do you run rounds right along the edges of legs or stiles, when aprons and rails will be flush jointed into them?
The answer is yes you do, and furthermore you make use of a little known device that's known in some workshops as the bumcheek moulding! Basically it's whenever a round or bead is butted up against another round or bead. Here's what it looks like,
So I've fitted a 2mm or 2.5mm round over bit in a router table (Wealdens new "arris bits" are magic) and run all the long edges of every component through,
You could set up a cross cut slide on the router table to make the corresponding cut on the ends of the stretchers/stiles, but I prefer to just form them by hand with some 180 grit on a hard sanding pad (if you use a soft pad you'll dub over the corners which looks horrible).
The bumcheek moulding removes at a stroke the problem of making flush joinery perfectly "flush", as long as you're within 0.1mm or even 0.2mm the joint feels flush even if it isn't. This is key to taking full benefit from the speed potential that a domino machine affords. The other advantage is it adds a neat little shadow line which makes your joinery look really professional. I use it all the time in all sorts of applications,
Here's a Shaker style cabinet I made last month, you can just see how the face frame stile is jointed to the cabinet's side using this device. Thoroughly recommended!
Attachments
custard
Established Member
On to the glue up, which in turn raises a few problems.
The first is a general question of what glue is best for domino joinery? In this particular case I don't have a choice, the timetable for this build means I have to use quick setting PVA. But under other circumstances I'd seriously consider a UF glue like Cascamite or Bordens. The reason is that even on an ultra simple project like this there are 30 mortice and tenon joints, if you were to try and do them all in one go with PVA you'd have to move like greased lightening to finish it within the glue's open time, where as with UF you could take your time. Especially as for the strongest possible joint you need to apply glue to both the mortice and to the tenon. Furthermore, even though PVA has a published open time, I'm convinced that it's actually pressure sensitive, so a partly assembled, tight domino joint, could actually grab and set hard before you've got the cramps on to close the joint fully. There's also the fact that many workshops routinely sand down the surface of the domino biscuits to make test assembly and disassembly easier, UF is gap filling but PVA is not.
But that's all theoretical, I need to get the first coat of finish on tonight, so I'll glue up the two end components with PVA, wait 45 minutes, then glue the cross stretchers in. With UF I wouldn't be able to take it out of cramps until tomorrow. The issue I'll have to take care over is squeeze out. I'm determined to apply glue to both the mortices and the tenons, so there'll definitely be some squeeze out. I'll scrub down around the joints with boiling water and a stiff toothbrush then pat it dry with kitchen roll, furthermore I'll repeat that three times! Is that a faff? You're dead right it is, but no where near as much faff as seeing my oil finish ruined by squeeze out and then having to scrape and sand it clean before re-oiling.
I keep meaning to try out that special Titebond PVA that fluoresces under black light. Has anyone ever given that a go?
The second problem is how to cramp up angled components?
On a really prestige job (so not this one!) I wouldn't hesitate to glue on specially shaped cramping blocks and then saw them off after the glue up and finally plane off the residue. But for this I need something fast, basically a shaped cramping block that can itself be cramped onto the component rather than be glued on.
In the past I've made these detachable cramping blocks up to specific angles from scrap, you can see one in this photo. But recently I saw these more versatile aluminium alternatives sold by Classic Hand Tools. They work great, but rather than buy more I think I'll just make some by turning a 50mm cylinder of hard timber, splitting it in half, slicing it into sections, and gluing the semi-circles onto sections of plywood with sandpaper glued on to the other side.
Anyhow, with both ends glued up (and carefully checked for squareness and even more importantly, for any twist) I'll drill out and countersink the stretchers to attach the top.
With the ends glued and done it's time to connect them via the four stretchers. I always make sure I do the final assembly of any piece on a flat surface so as not to introduce any twist or wind into the piece. Normally I'd use my saw horses and shim them level, but the Leadwood slab is currently sitting on them, so I built two simple bearer platforms on the floor and sighted them like winding sticks. It doesn't matter if one is slightly higher than the other, but it is critical that any wind is shimmed out.
Now, while that is curing I'll grab a bite to eat and then apply the first coat of Osmo.
The first is a general question of what glue is best for domino joinery? In this particular case I don't have a choice, the timetable for this build means I have to use quick setting PVA. But under other circumstances I'd seriously consider a UF glue like Cascamite or Bordens. The reason is that even on an ultra simple project like this there are 30 mortice and tenon joints, if you were to try and do them all in one go with PVA you'd have to move like greased lightening to finish it within the glue's open time, where as with UF you could take your time. Especially as for the strongest possible joint you need to apply glue to both the mortice and to the tenon. Furthermore, even though PVA has a published open time, I'm convinced that it's actually pressure sensitive, so a partly assembled, tight domino joint, could actually grab and set hard before you've got the cramps on to close the joint fully. There's also the fact that many workshops routinely sand down the surface of the domino biscuits to make test assembly and disassembly easier, UF is gap filling but PVA is not.
But that's all theoretical, I need to get the first coat of finish on tonight, so I'll glue up the two end components with PVA, wait 45 minutes, then glue the cross stretchers in. With UF I wouldn't be able to take it out of cramps until tomorrow. The issue I'll have to take care over is squeeze out. I'm determined to apply glue to both the mortices and the tenons, so there'll definitely be some squeeze out. I'll scrub down around the joints with boiling water and a stiff toothbrush then pat it dry with kitchen roll, furthermore I'll repeat that three times! Is that a faff? You're dead right it is, but no where near as much faff as seeing my oil finish ruined by squeeze out and then having to scrape and sand it clean before re-oiling.
I keep meaning to try out that special Titebond PVA that fluoresces under black light. Has anyone ever given that a go?
The second problem is how to cramp up angled components?
On a really prestige job (so not this one!) I wouldn't hesitate to glue on specially shaped cramping blocks and then saw them off after the glue up and finally plane off the residue. But for this I need something fast, basically a shaped cramping block that can itself be cramped onto the component rather than be glued on.
In the past I've made these detachable cramping blocks up to specific angles from scrap, you can see one in this photo. But recently I saw these more versatile aluminium alternatives sold by Classic Hand Tools. They work great, but rather than buy more I think I'll just make some by turning a 50mm cylinder of hard timber, splitting it in half, slicing it into sections, and gluing the semi-circles onto sections of plywood with sandpaper glued on to the other side.
Anyhow, with both ends glued up (and carefully checked for squareness and even more importantly, for any twist) I'll drill out and countersink the stretchers to attach the top.
With the ends glued and done it's time to connect them via the four stretchers. I always make sure I do the final assembly of any piece on a flat surface so as not to introduce any twist or wind into the piece. Normally I'd use my saw horses and shim them level, but the Leadwood slab is currently sitting on them, so I built two simple bearer platforms on the floor and sighted them like winding sticks. It doesn't matter if one is slightly higher than the other, but it is critical that any wind is shimmed out.
Now, while that is curing I'll grab a bite to eat and then apply the first coat of Osmo.
Attachments
custard
Established Member
I think what you really need is a 41 year old grumpy apprentice that has a lot to bring to the job Custard. Your workshop would have the cleanest windows it's ever had. So that's a start. Thanks for the build. It's fascinating it really is.
MattRoberts
Established Member
Love build threads! Thanks for going into the detail, really interesting. Love that wood!
A great material for shims is polypropylene, particularly in 500um or 800um thicknesses.
It's pretty much indestructible but can be cut easily with normal tools (sheet metal shears work particularly well).
It's pretty much indestructible but can be cut easily with normal tools (sheet metal shears work particularly well).
Wizard9999
Established Member
Top class thread Custard, like others I want to thank you for taking the time to post this, especially as you are taking the time to do so when you are also trying to get the piece made to a tight client deadline. =D> For you this may be a super simple project, but for me there are a whole range of things to take from it, and that is just on first reading. Trust me I will be reading it again in the future and I am sure it has a lot more to give me.
Once you have finished, if you do have a second I do have one immediate question. If I understand the sequence of events correctly components are machined, joint positions marked up and then domino mortices are cut. You then mention cleaning off the pencil marks, etc. either by planing, sanding or both. I guess this is the point at which your 0.5mm allowance comes in? Having gone to such an effort to ensure the perfect alignment of the components with your shimming, etc. how do you deal with the risk that the planing / sanding doesn't introduce inaccuracy?
Thanks again for your Christmas gift of a thread!
Terry.
Once you have finished, if you do have a second I do have one immediate question. If I understand the sequence of events correctly components are machined, joint positions marked up and then domino mortices are cut. You then mention cleaning off the pencil marks, etc. either by planing, sanding or both. I guess this is the point at which your 0.5mm allowance comes in? Having gone to such an effort to ensure the perfect alignment of the components with your shimming, etc. how do you deal with the risk that the planing / sanding doesn't introduce inaccuracy?
Thanks again for your Christmas gift of a thread!
Terry.
