Some time ago I built a flying model of Leonardo’s helicopter – so many people said it would never fly, but I had read that the original was based on a flying toy, and proceeded on that basis to make a toy using technology available in teh Renaissance period to make a flying model of Leonardo’s helicopter. And it worked (ok not very well, but it did work). You can see the results here…
You can buy commercial models, such as from Gakken in Japan, but I think it’s more interesting and fun to build your own at a fraction of the price 🙂
Cheers
Jerry
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Posted by Jerry on October 5th, 2007 — Posted in Journal, Woodwork
I wasn’t happy with the breadboard ends – there was too large a gap between the breadboard ends and the rest of the table top, and I wasn’t happy with the amount of play in the end dowels. So, as the saying goes “if it offends thee, cut it off…” Out with the circular saw guided by a board carefully lined up square and clamped to the table.
I then chiseled off the stubs and re-dressed the jarrah on the jointer. Next, I re-drilled the outer dowel holes so there was only about 3mm play to allow for expansion and reassembled the ends. Much closer fit, and better support from the breadboard supports for the (now slightly shorter) table top.
Then it was a quick trip to the hardware store to get some fiberglass resin – polyester resin and hardener, and set about filling the sap cavities – using two steps for the deeper ones.
After allowing it to set, I began sanding the top. The excessive vibration on the triton orbital sander attachment gave brief warning before the yellow sponge pad parted company with the balance weight and flew across the table shedding a yellow powder. Well, the instructions did say it was not recommended for use on varnished surfaces! Friction from the resin overheated the attachment in exactly the way that oil finishes don’t – and I paid the price. AUS$39 for a new sponge pad. I’ll still use it for the final finish, but the initial sanding will be by belt sander.
I’m beginning to see why bespoke tables are so expensive! But we’re nearly there now (with luck). More after the finishing is complete and the top ready to mount onto the frame.
Cheers
Jerry
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Posted by Jerry on October 2nd, 2007 — Posted in Journal, Woodwork
In the morning I set out and managed to get a nice board of jarrah – a red mahogany-like Australian hardwood. It’s not cheap – as befits a high quality low volume timber.
And the contrast is excellent. I read a pile of articles on making breadboard ends, but I suspect that these are not WIDE breadboard ends because they talk of holding them in with a couple of dowels. Jarrah is dense and heavy, as is the rest of the table top. So I cast around my workshop for some ideas an decided that some 25mm square jarrah left over from the aprons were long enough to run as supports the length of the table.
I held the boards in with three dowels glued , and ran a bead of glue for about 200mm in the centre, figuring that any expansion would take place towards the outer edges. I then drilled dowel holes in the end-grain of the table top and glued the dowels in, but the outside ones in the breadboard ends I rendered as slots to allow for the movement.
I’ve probably allowed too much here, and I’ll assess that tomorrow – I may recut these.
Anyhow the top is glued up and is starting to look like the finished table. Here is the current stage, just prior to the sanding and finishing – It’s starting to come together now as a visual statement
The table top is now biscuited, glued and clamped and the glue should be cured by morning 🙂
Having set up the router on the Triton Mark 3 saw bench, and set up the biscuit jointer attachment I set about cutting slots for the 28 biscuits that make up the top – four biscuits per join, across seven joins (eight boards).
Relaxing over lunch I thought I’d check out what other users have said about the biscuit jointer attachment, and was surprised to find several advising against the Triton version on the basis that they couldn’t joint long boards to make, for example, bench or table tops. So I thought I’d set the record straight – you can cut biscuit slots in large boards. In fact the sliding extension table makes it very easy to handle large boards, such as when jointing pairs of boards to make up a table top.
And here’s the proof!
To make the table top I biscuit jointed the boards in pairs, and glued and assembled them and clamped them for about 2 hours, then I took the board pairs and biscuited them, finally setting them onto the Torquata panel clamps for the final full width glue-up. I set the lower clamp legs across the table frame, then laid out the boards in sequence and ran a glue line along each length, inserted the biscuits and closed the seam. Then onto the next and so on until the whole table top was assembled. Then I added the clamp upper and the hardware and clamped the whole thing tight.
Tomorrow I’ll make the breadboard ends – hopefully out of Australian mahogany-like jarrah to match the table aprons.
Cheers
Jerry
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Posted by Jerry on September 30th, 2007 — Posted in Journal, Woodwork
Further progress on the table –
I had previously dry-assembled the frame components and then the following day disassembled it and finished each component, sanding progressively from 320 grit to 1500 grit on the legs and apron pieces. Then I finished each component with Rustins Plastic Coating – which is not as drastic as it sounds. In this case, plastic means pliable or flexible. And unlike most two-part acrylic finishes, this one is an alkyd lacquer – which has the best characteristics of oil and acrylic – it has the flexibility and deep lustre of oil, but the drying time of an acrylic. I was wary of it at first, but the trial pieces came up good with just one coat.
I gave the apron and legs one coat then sanded with 1500 grit, then finished with an Organoil wax/citrus oil polish and buffed it to a nice satin finish.
I then assembled and glued up the frame, setting it upside down in the car port. i clamped it with a ratchet tie-down, cross measured to ensure it was square, and checked that the legs were vertical in both planes with a square. Satisfied with that I left it to dry overnight.
The next day I cut and finished a cross piece from jarrah and glued and doweled it in position at the half-way mark using Triton PVA glue.
The ash dowels make a nice contrast with the red jarrah.
Next job was cutting the corner braces and fitting them – I pocket screwed them to the side aprons then drilled and used self-drilling hex screws into the legs – I had chamfered the inside corner of the leg for this purpose. And that completed the frame, making a firm yet light frame well able to bear the weight of the ribbon-gum top.
I re-checked the boards for the top and thicknessed a couple of them to ensure an even thickness across all the boards.
Then it was time for a clean-up of the workshop – offcuts and tools stowed and the floors and surfaces vacuumed before setting up for the next phase – making the table top.
I removed the top from the trusty Triton Mark 3 saw bench and put on the router top after ensuring the router was well centred in the router base. Then I attached the biscuit jointer attachment and removed the end-stop as I will want to position biscuits along the length of the two-metre boards. The biscuits function like loose tenons and provide additional face-face gluing surface as well as aligning the boards along one plane, leaving a little room for edge-edge slippage to ensure a good glue spread. I recommend the Triton system – a good Australian invention that just keeps getting better. Although I was a little dismayed that at the Working with Wood Show the triton folks were offering a $100 trade in on any Mark 3 table top. It looks like they are no longer maintaining their philosophy of continuous backward compatibility with earlier models. Mine was made in around 1985 and I have until now always been able to add components using adapters so my basic saw bench remained as versatile as the latest model. But no matter – I think I’ve got all the attachments I need for the moment 🙂 thanks to several years of Wood Show specials!
I then did a test cut on some some off-cuts to ensure that the height was adjusted correctly.
I like the safety mechanisms and dust extraction on the triton, as well as the fact that you cut both timbers at once to ensure perfect alignment every time, and finally, because the jointer is in the table, your hands are free to hold and stabilise the stock.
My task for tomorrow is to cut the biscuit slots for the top and assemble and glue up the top, then square off the ends, and prepare two boards for the breadboard ends. After that I shall attach the breadboard ends, fill the sap cavities with fibreglass resin and then will come the final finish – sanding flat, rounding the edges, and a couple of coats of Rustins Plastic Coating and a final wax. The top will be attached when the table is inside the house, using figure-eight table clips. So the end is in sight.
You will be able to get a complete narrative of the construction process by clicking on the Woodworking category of this blog.
