Cheshirechappie
Established Member
So far as using triangles to divide a line, I certainly don't claim any originality - I learned it in Engineering Drawing lessons at school, and the method probably predates the invention of the ruler!
I do like the Sector though - wonderfully simple. I might just have to make one of those. Thanks, Alf!
There are a couple of old engineering tricks for adjusting firm-joint dividers, which tend to be a bit 'jerky' to adjust by hand pressure on their legs. If you want to close them up a smidgen, hold by one leg and knock the other on the edge of the bench - you get to know how hard to knock your particular pair, but it's usually a harder knock than you might think. If you want to open them up a gnat's, turn them upside down, hold by one leg, and knock the joint on the bench top. Again, how hard depends on the particular joint firmness of your pair. Fitters and turners used to adjust their dividers and callipers to a nicety by this method - adjusting by the odd 'thou' was quite easy with a bit of practice - we don't need that level of precision!
For woodworking, the engineer's type dividers with the slender legs can be quite flexible once they get bigger than about 4" or so. I prefer the older-type chunky ones, often fitted with a wing and lock. If the joint is as firm as it should be, the wing lock isn't really needed, but it is an extra insurance against knocks when it's lying in the bench tool-tray. Axminster do a good new one - bought it off them a couple of months ago, and was impressed. It comes with a pencil holder and a (rather useless) carbide scriber with a plastic stem, but the basic divider is solid and well-made. It's a woodwork only tool, though - the points are not hard enough to last when marking metals. Against that, the modern engineer's sort are hard enough to mark metals happily if you need to, and most new ones have a fine screw adjustment which some people prefer to the knocking method. They all work fine if you use them with suitable care and regard for their limitations.
I do like the Sector though - wonderfully simple. I might just have to make one of those. Thanks, Alf!
There are a couple of old engineering tricks for adjusting firm-joint dividers, which tend to be a bit 'jerky' to adjust by hand pressure on their legs. If you want to close them up a smidgen, hold by one leg and knock the other on the edge of the bench - you get to know how hard to knock your particular pair, but it's usually a harder knock than you might think. If you want to open them up a gnat's, turn them upside down, hold by one leg, and knock the joint on the bench top. Again, how hard depends on the particular joint firmness of your pair. Fitters and turners used to adjust their dividers and callipers to a nicety by this method - adjusting by the odd 'thou' was quite easy with a bit of practice - we don't need that level of precision!
For woodworking, the engineer's type dividers with the slender legs can be quite flexible once they get bigger than about 4" or so. I prefer the older-type chunky ones, often fitted with a wing and lock. If the joint is as firm as it should be, the wing lock isn't really needed, but it is an extra insurance against knocks when it's lying in the bench tool-tray. Axminster do a good new one - bought it off them a couple of months ago, and was impressed. It comes with a pencil holder and a (rather useless) carbide scriber with a plastic stem, but the basic divider is solid and well-made. It's a woodwork only tool, though - the points are not hard enough to last when marking metals. Against that, the modern engineer's sort are hard enough to mark metals happily if you need to, and most new ones have a fine screw adjustment which some people prefer to the knocking method. They all work fine if you use them with suitable care and regard for their limitations.
