1939 forum posts
If anyone is after a cheap 60cm steel ruler there is some in Poundland for a quid. I know it's not he best but it's better than I had before.
|Peter Miller||03/08/2019 18:43:18|
11771 forum posts
I haven't seen it but from past experience, just place the edge up against a straight surface.
I got a beautiful 1 metre aluminium rule from Woolworths many years ago. Yes it is straight but three others were not when I tried them
|John Stainforth||04/08/2019 00:15:31|
|406 forum posts|
To check whether a straight edge is straight, just look down it. The eye is as good as a laser beam for judging that.
931 forum posts
Well said, that man. I once worked with a car designer who could look at a clay model and spot if it was out one side to the other, by as little as half a millimetre. "yeah sure", we scoffed and measured the model again on a Stiefelmayer measuring machine (accurate to 1/100th of a mil.) and he was spot on! The eye is astonishingly accurate.
BTW, to be pedantic it's a steel rule. A ruler runs a country.
1939 forum posts
It's difficult to tell if it's streight in the shop as its in a plastic sheath with a cable tie round the top so you can't slide it out. So far it's seems ok, a bit on the flexable side though but still better than what I had before. My other was hinged in the middle which made it stand off surfaces over 30cm and it made using cutting blades tricky.
|Martin Dance 1||04/08/2019 09:03:08|
|221 forum posts|
Simplest way to check the straightness of a rule or straightedge is to place it on a flat surface, a piece of white contiboard is ideal and using a sharp pencil draw a line along the edge(s).Then flip the rule/straightedge over and align the same edge with the pencil line at the ends of the rule/straightedge. Now draw a second line. It should coincide exactly with the first line, if not it's not straight.
|Geoff S||04/08/2019 10:24:36|
|4035 forum posts|
... and of course lasers aren't very good if you want to slice a straight line with a scalpel.
As John says, an eye along its length soon shows up any errors, as it does when checking the alignment of wing and tailplane on a build.
|Ray Wood 4||04/08/2019 16:13:29|
268 forum posts
Spent £40 on a 1 metre steel rule 30 years ago, best money I ever spent !!
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