Tuesday, 17 May 2011
I have just received these wonderful holdfasts, tenderly hand crafted by Richard T of UKWorkshop fame (who says they don't make anything in the Midlands any more eh!)
So the next thing I needed was a 3/4" Forstner bit to make the holes for them, but believe it or not, between my collection, the collection I inherited from my Dad, the odds and ends box and the stock in the shop there was not one 3/4 inch bit to be found!
Not to worry, a quick purchase order to the nice people at FAMAG and a big box of goodies arrives. I plumped for 19mm (3/4 inch = 19.049mm) so they are only half a gnats undersize and will slot neatly into our existing product range. If anyone ever needs imperial bits we can get them in in about a week - just drop me an email.
I suspect there may be others in a similar predicament so I have taken the libery of ordering a few more, listing them on the site and putting them on special offer.
Now comes the next question. My benchtop is about 50mm thick, and I've got a sheet of 12mm MDF and a sheet of 9mm ply winking at me and suggesting that they would love to be glued and screwed to the underside in a double sandwich taking it up to 82mm - nearly the full depth of the apron. The forstner will happily do 60mm on its own or up to 410mm with an extension, so either way putting the holes in is no problem.
Will the extra mass be worth it?
Will the holdfast holes wear better if they are in thicker material?
Have I got the time to do it, or will it become just another job on the list?
Whatever happens, I'll keep you posted.
Saturday, 14 May 2011
The interface between tool and user is a critical component of tool design and even subtle changes can have a marked effect on how the tool works.
Take this beautiful Thomas Turner tenon saw for example, the grip is reasonably vertical with a pronounced bulge in the back. To understand the reason for this we need to consider the 'hang' of the handle. A tool with a straight handle (like a gents saw or a carving knife) gives a great deal of control. Wafer thin slices of roast beef or finely executed joinery... In contrast a tool with a more vertical handle (like a steel framed bowsaw or a plane) is all about maximum transfer of power.
In this example we have a bit of both but the emphasis is on power. English backsaws can be steered left or right for the first few strokes, after that the kerf, gravity and the set (the amount by which the teeth protrude left and right from the saw plate) take over and do all of the steering for you. To begin the cut with this saw you would grip at the top with your thumb and extended forefinger and relax the rest of your hand to maximise your control.
With the workpiece secured in the vice so that the cut is plumb , all you have to do is feel for the zero moment when the back is directly over the teeth and gradually allow more of the saw's weight rest on the workpiece. With a new saw you have the advantage of being able to observe the reflection of the timber in the side of the saw plate too - if the reflection seems to carry on straight through you know the saw is plumb. With an old one you need to be more conscious of feeling for vertical, the weight of the saw is all in the heavy brass back, making it more 'tippy' so the point of balance should be relatively easy to feel for.
Once the kerf is established you can relax your thumb and forefinger and tighten up a touch with your little finger and the heel of your hand, this changes the grip from the top part of the handle to the bottom part - from control to power. By this stage there is no steering to do, the kerf is holding the spine perpendicular over the teeth, the spine is providing the weight to keep the teeth engaged and the set is ensuring that the left and right teeth are bearing equal measures of the work so the kerf stays straight. The faster you go on the push stroke, the more material you will remove with each pass, and as long as you don't grip too tightly and pull it off course, the cut will continue dead plumb and true.
Whether you are squeezing at the top for control or at the bottom for power, your grip should always be relaxed enough that you can feel the soft flesh of your fingers give a little each time you switch from pull to push, it really is a very light touch indeed.
With sharp teeth and a well balanced set I'd be happy to bet this saw will easily eat half inch oak at a rate of an eighth of an inch with each stroke. A new one with a much thinner plate and harder modern steel would possibly manage double that.
If you fancy having a go at fine tuning your own saw handle shape we have Atkinson Walker tenon and dovetail saws available in kit form with full instructions and downloadable templates. The Pax 1776 range were also designed to be adjusted to suit the individual user, the finish on the handles is just straightforward Danish oil (tung oil) so any alterations you make can be easily blended into the original finish.
Wednesday, 4 May 2011
There are 13.5 times as many people living in slums around the world as there are people in Britain. They live in houses made from little more than rubbish and ingenuity. Poor sanitation and lack of electricity promote disease and illiteracy and if they manage to evade those two ills they have a good chance of being injured by their own roof falling in. To still have a problem this fungible, on this scale, in this day and age is not a very impressive record for humanity.
The 300house project is the brainchild of Vijay Govindarajan and has developed from a thought he posted on the Harvard Business Review Blog into a well organised project gathering ideas from business, individuals, universities, governments and professionals.
The idea isn't new, post war prefabs were a response to a similar problem. The execution however is very different, using the internet to join up freely given ideas from around the globe to provide a complete solution. From governments finding ways to facilitate land ownership, banks to provide microfinance loans and blokes in sheds to come up with ingenious ideas like bean tin methane stoves or everlasting biological light bulbs.
So if you happen to wake up one morning with an idea for a universal multi-material joinery system but don't have the means or desire to make it a reality, here's a way that your idea could be shared and contribute to changing the lives of a whole lot of folk.