Concertina gauge?

| Watching Paul Bradburn the other day and he used an interesting | little creature which (I think) he referred to as a concertina | gauge. Basically it's a little doohickey that rests on a surface | and can be stretched so that each end is on a desired point on that | surface. It then automatically divides the distance between the | two points into equal sub-lengths and you can mark them off | accordingly. This would be handy for decoration among other | things. I've done some searching in the UK but I can't locate one. | Any ideas?

Is this what you're looking for?

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Old carpenter's trick is to use a rule angled across the board. Determine how many divisions you want (2,3,4...). Place one end of rule at side of board, and angle ruler across so that that number of divisions is at the other edge.

An example is easier - I have a 6" board and want 8 divisions. I put the zero mark on the ruler at one edge of the board, angle the ruler across so the 8" ruler mark is at the other edge. Then mark the board where the 1", 2", 3" etc. ruler marks are.

Harder to explain than to do.

Regards.

In addition to woodworking stores, they are also sold in drafting supply and sewing stores.

FoggyTown

That's how I do it. I keep freaking people out with it..sometimes running into arguments/discussions that it doesn't work *VBG*

It is a bit counter-intuitive until you do the mental geometry, isn't it.

Except that it's much "harder to do" when the number of "divisions" you want is less than the width of the board. :)

That old "trick" is indeed neat, but here's something that takes parallax, and the math, out of another measuring problem ... very useful when you need to figure out the number of slats/spindles/boards/posts/etc of known size that need to be evenly spaced between two points/edges/aprons/legs/etc, which is something I keep running across when making furniture..

The older you get the more the PITA having to rebuild the wheel every time, hence the simple equation formulated into an Excel spreadsheet so I don't have to fiddle around remembering how I did it the last time ... of course, you have to have a computer or calculator handy (it works just fine with my Construction Master IV, when I get lucky with the keystroke sequence):

Use the 1/2" marks intead of the 1" marks. Or 1/4" if necessary.

Let me think. I can do what I want using any old ruler OR by buying a shiny new toy to play with. Hmmmmm . . .

FoggyTown

it works fine, as long as the sides are parallel and long enough to accomodate your diagonal. of course, those requirements cover a lot of ground.

Ahh ... but suddenly the 'elegance' of the trick starts disappearing ... and try that on a 5" x 5" square workpiece where you want 4 divisions. ;)

Admittedly, in many instances, you can double the width and go in 2" increments instead of 1" (providing the piece is long enough for the diagonal to fit on), but then the "old carpenters trick" starts to lose, as above, its elegant simplicity.

Not ragging on you ... but every tool/trick has it's limitations. ;)

The devil is always in the details and while most problems have a "common sense" solution, that solution is usually wrong in that it ignores some extraneous factors that are, in fact, critical.

Regards.

Common Sense is the least common of human attributes.

S. Clemens

That takes a Hmmmmmm ???? Toys Rule!