Tuesday, 22 January 2013

The Chair Back Continued

Once each of the three bent laminations was ready and removed from the form the edges were jointed and then ripped to width to make them paralel.  This allows for a more accurate cleanup of the glue and which then allows for another round of jointing and ripping on the table saw.  This is done taking off as  little as possible.  Once done each of the three peices looks pretty much like this. 

One bent lamination jointed and ripped, ready for joining. 
With the three of them done I was able to mix and match for the best grain alignment and cleanest of joints.  Even though the form to make these was itself made form only one half of the curve there was a minor difference side to side which defined each of the three laminations with a definite left and right side .  Imperceptible to the touch of the back but a misalignment of 1/16th of an inch glares out when looking at curves that run parallel. 

All three bent laminations standing on top of each
other in their eventual configuration. 
When ripping the final width of the center lamination I also ripped the width and height of the insert square that will the the detail inthe centre of the chair back.  This is cut from a solid block of walnut which is thicker than the rest fo the parts to allow for final fitting when completed.  The imterior thickness of the block was reduced using a router so that only the middle 1/4 inch remained.  Then, pilot holes were drilled in the empty space and the outline of the tree was cut out with a fret saw. 

Rough shape after the fret saw. 
After roughing out the shape the edges and profiles were broken and refined with a set of small files.  This peice is almost finished and took quite a while to do but I think the results will be worth it when all is said and done. 

After refining with some small files. 

Tuesday, 15 January 2013

The Tree Table

So I have just started to work on a new project, it is a writing desk and chair set.  The set will be made of Canary wood and Walnut.  I have jumped right into this project and have many components in the works so I will just pick a few of the more interesting ones to write about. 

To give an idea of what I will be working towards here is a snapshot from sketchup of the piece and some of the parts cut to rough length. 

Sketchup Model

Note the beautiful grain and color in the quarter sawn canary wood.

The back of the seat will be built using a bent lamination process on the canary wood to create three 3.5" wide curved strips.  The middle strip will be cut apart to allow for the insertion of a block of walnut with a piercing of a tree inset within it.   

 First step was to build the bending form.  The desired width of the seat back is 17", I built the form 20" wide to allow for trimming.  The curve was drawn out on one peice of 1/2" MDF which was roughed out on the bandsaw.  The curve was then faired using a rasp and file untill both sides matched.  Once the first layer of MDF was accurate layers were added to each side and trimmed flush at the router table.  Eight layers were used to create a bending form 4" thick, just wide enough to bend the components for the seat.  

Using a bearing bit to flush trim the MDF form.

Once the form was ready and the plies of canary wood had been thickness planed to 1/8" they were covered with glue and clamped to the form.  A common problem with bending wood is spring back.  Regular carpenter's glue is used, and though in most applications an hour is sufficient, in bending to curves there are additional forces at work.  When a drop of glue sits out for an hour it may be dry to the touch but it can still be deformed with pressure and is not fully hardened.  However, if allowed to stay out for a full day the glue is considerably harder.  It will chip rather then bend or deform.  Using this logic my friend Dave always recommends leaving a curve in the form for a full day and then keeping pressure on the curve to help the glue fully harden in the proper form.  I am letting these three laminations sit in the form for two full days to be extra sure.  As they will need to be joined edge to edge I am trying to ensure they stay as consistent as possible. 

The form in use, bending six 1/8" plys.

Note the full width blocks to ensure equal pressure across the width of the curve.

New Members in the Chisel Family

So it has been a little while since I posted anything.  After the timber framing course things were pretty hectic through Christmas and afterwards.  A bunch of my family chipped in and gave me a pair of timber framing chisels for Christmas which is really exciting. 

I've been anxiously waiting their arrival, each day checking the status of their delivery on the USPS website.  My friend Jamie said it reminded of him of the Calvin and Hobbes comic strip where Calvin orders a propeller beanie in the mail and it takes 6 weeks to arrive.  It's worth checking because it is actually quite accurate.  


Today they finally arrived!!!  Thanks to my generous family I now have 1.5" and 2" Barr Quarton timber framing chisels in my arsenal.

The New Chisels, 1.5" on the left, 2" on the right

The Quartons measure 17.5" long but are no match for the Smith original that my brother made for me for Christmas.  The Smith original is 6" in width and has a new home on the wall in the shop where I will see it every day.  Thanks bro for one of the coolest Christmas presents ever!!! 

The Smith Original in its New Home
A small addendum on setting up the new chisels; To truly make a chisel sharp both the back and bevel need to be sharpened to a high degree.  The edge can only be as good as the worse of the two planes which intersect.  As a result when I get a new chisel I try to take the time to flatten the back, which, luckily only needs to be done once.  Often this means putting on a movie and lapping the back of a set of small chisels in an evening.  However, these chisels are much larger than my others and thus I knew it would take longer.  How much longer was a mystery I was going to have to find out the long way.  Over the past week I have had a couple of late nights and watched more movies than I normally care to.  It turns out I could have almost watched the entire Lord of the Rings trilogy (extended edition) in the time it took to fully lap the backs of these beauties.  I wound up putting a little more that five hours into each one. 
Before lapping the back.
The slurry produced in a few hours of lapping.
After lapping the back.