It is currently 28 Mar 2024, 13:05
StevieB wrote:Given this works due to the arms being the exact length for 90 degrees, presumably one arm (the one that goes into a corner) being twice the length of the other two arms would give 45 degrees and 2/3rds would give 60 degrees?
Steve Maskery wrote:...... The stock must be straight.......
Cabinetman wrote:I thought I’d knock up a cheap and cheerful one this afternoon, easy to get all the arms the same length by screwing it together and then making the long bits same length as the short bit when it’s turned round each time, got that bit right. But it wasn’t right, turned the small arm to stick out one way and it wasn’t quite 90° turned it the other way and it was slightly more than 90°
I drilled the hole in the centre of the width of the rail by eye, normally my eye is pretty spot-on. But I must’ve been such a small amount out and it’s thrown the whole thing straight in the bin!
So there is a lesson for anybody else wanting to do it, absolute accuracy on centring the hole gentlemen and possibly ladies. Ian
Mike G wrote:Steve Maskery wrote:...... The stock must be straight.......
I beg to demur. So long as the points and the pivot are all in exactly the right place, the stuff in between can be any old shape (so long as they stay out of the way of whatever is being measured).
Mike G wrote:I've said it before, but it's worth repeating......the best way to make one of these is to make the short arm first, fix it in place on the long arm, and use the point on the short arm to mark the ends of the long arm. No measuring.
Andyp wrote:Take a stick. cut a little more than one third of it off. Make a hole in the long piece roughly in the middle. Make a hole roughly in the end of the short piece. Attach the two pieces together with a nut and bolt. The short piece because it was more than one third of the original stick will be longer, when swivelled, than each end of the long stick. Cut the points of the short piece and one end of the long at the same time. Now swivel the short piece to the other end of the long piece and use that as a pattern to cut the other point of the long piece. Et voila.
TrimTheKing wrote:Mike G wrote:I've said it before, but it's worth repeating......the best way to make one of these is to make the short arm first, fix it in place on the long arm, and use the point on the short arm to mark the ends of the long arm. No measuring.
That’s what he’s already said he did Mike,......
spb wrote:Andyp wrote:Take a stick. cut a little more than one third of it off. Make a hole in the long piece roughly in the middle. Make a hole roughly in the end of the short piece. Attach the two pieces together with a nut and bolt. The short piece because it was more than one third of the original stick will be longer, when swivelled, than each end of the long stick. Cut the points of the short piece and one end of the long at the same time. Now swivel the short piece to the other end of the long piece and use that as a pattern to cut the other point of the long piece. Et voila.
The only change I'd make would be to cut the first end as you describe, but then use the point of the short piece to draw an arc across the other end of the long piece. Then take a straightedge from the point you just cut on the long piece, through the centre of the pivot, and mark the intersection with the arc you drew. Cut your last point exactly there.
Alternatively, mark a straight line along the length of the long piece before cutting anything, and be sure to drill your pivot hole and cut both points along it. Either way, the important thing is that the centre of the pivot and the two points are all in a perfect straight line.
As an aside, if the pivot is offset from the line between the two points, you'll still have a device that will measure an exact angle; it just won't be 90 degrees.
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