The maths behind cutting these bevels?

[Adam W.]

You told me to post a video of it and I can't be bothered to trawl google and find a good one. It's easy to find if you want to look for it yourself.

 

[mudman]

It’s a trick question I bet the answer is I want to keep it!

The answer is that it is twice the distance from the middle to one end. (Isaac Asimov)

 

[mudman]

OK, prove to me that geometry is mathematics.

I think you're either trolling or too pig-headed to admit you're wrong.
You have had several definitions posted here that define geometry as an a branch of mathematics. I think the onus is on you to prove it is not, not the other way around, so let's see it, what is your proof that refutes everything that has gone before here?
But, in true troll form, I predict you will either ignore the challenge or come back with some ridiculous pithy remark that has no greater rigour than a 'Because I said so'.

 

[mudman]

I just described an arc. It measured exactly 112mm. The arc came before the measurement, which wasn't necessary at all!
Arc with no measurement, no problem.
Measurement with no arc, meaningless.

What on earth are you blathering on about?

 

[johna.clements]

You told me to post a video of it and I can't be bothered to trawl google and find a good one. It's easy to find if you want to look for it yourself.

I will conclude that your method does not in fact exist. I described a method in words then posted a video which was on the first page of my search. Here is the video again that was on the first page of my search, I picked because it was one of the shortest and did not want to watch lots of video. But I think it describes the method quite well and if you learnt it in school the thumb nail would remind you.

We were taught this in maths back in the 70s.

 

[Tom K]

You told me to post a video of it and I can't be bothered to trawl google and find a good one. It's easy to find if you want to look for it yourself.

 

[johna.clements]

I think you're either trolling or too pig-headed to admit you're wrong.
You have had several definitions posted here that define geometry as an a branch of mathematics. I think the onus is on you to prove it is not, not the other way around, so let's see it, what is your proof that refutes everything that has gone before here?
But, in true troll form, I predict you will either ignore the challenge or come back with some ridiculous pithy remark that has no greater rigour than a 'Because I said so'.

I agree.

 

[Jacob]

I agree.

Lost the point really.
Which is that it's perfectly possible to do all manner of complicated designs and details graphically, without any recourse to mathematics, in fact with total ignorance thereof.
And it is the solution to the OPs dilemma, whereas maths is his problem
I'll do some photos when I have a chance - of how to divide a line precisely, with dividers, without the geometric constructions above. It's really useful to know, but not that difficult to work out for yourself.

 

[Tom K]

Lost the point really.
Which is that it's perfectly possible to do all manner of complicated designs and details graphically, without any recourse to mathematics, in fact with total ignorance thereof.
And it is the solution to the OPs dilemma, whereas maths is his problem
I'll do some photos when I have a chance - of how to divide a line precisely, with dividers, without the geometric constructions above. It's really useful to know, but not that difficult to work out for yourself.

I would normally set my dividers to an approx size, step off three times and adjust slightly depending if the final step overshot or undershot it seems to work well enough for most things.

 

[Jacob]

I would normally set my dividers to an approx size, step off three times and adjust slightly depending if the final step overshot or undershot it seems to work well enough for most things.

Exactly. But it's potentially very precise - dividing by 3 you adjust by 1/3 of the error, as near as you can judge. And again if a small error remains.

 

[Adam W.]

I think you're either trolling or too pig-headed to admit you're wrong.
You have had several definitions posted here that define geometry as an a branch of mathematics. I think the onus is on you to prove it is not, not the other way around, so let's see it, what is your proof that refutes everything that has gone before here?
But, in true troll form, I predict you will either ignore the challenge or come back with some ridiculous pithy remark that has no greater rigour than a 'Because I said so'.

Oh dear. You said it was a fact, surely that would be easy to prove.

I will conclude that your method does not in fact exist. I described a method in words then posted a video which was on the first page of my search. Here is the video again that was on the first page of my search, I picked because it was one of the shortest and did not want to watch lots of video. But I think it describes the method quite well and if you learnt it in school the thumb nail would remind you.

There you go.

It's not the best video, but it's what you want I guess.

Edit: I suppose I should explain why it's more accurate than your method, and it's because the dividers are fixed, whereas your method relies on you holding the ruler at a fixed position whilst moving the square and pencil at the same time. If your ruler sneaks off line, you create an error without noticing it.

And I should add that Mr mudman has lost the argument as soon as he started slinging insults. Poor show old chap.

 

[mudman]

And I should add that Mr mudman has lost the argument as soon as he started slinging insults. Poor show old chap.

And thus you prove my contention and lead me to believe that you are indeed, probably a bit of both. I could have gone further, if it wasn't that you obviously display an above average level of intelligence. However, your continued assertions are quite plainly ridiculous and so I can only conclude that you are doing it for effect and the desire to 'stir things up'. There is no arguing with people like yourself, so I will not try.

 

[johna.clements]

Oh dear. You said it was a fact, surely that would be easy to prove.

There you go.

It's not the best video, but it's what you want I guess.

Edit: I suppose I should explain why it's more accurate than your method, and it's because the dividers are fixed, whereas your method relies on you holding the ruler at a fixed position whilst moving the square and pencil at the same time. If your ruler sneaks off line, you create an error without noticing it.

And I should add that Mr mudman has lost the argument as soon as he started slinging insults. Poor show old chap.

I doubt that is more acurate. There are far more steps each with there own error.

 

[baldkev]

How was everyones day? I had a burger for lunch.... it was beef, onion and honey with a sprinkling of pepper, topped with a bit of crispy bacon and a slice gouda in a brioche bun ive got a george foreman on site for warm lunches
( we had them last night and i always make a spare for the next day )

I ( last week ) bought a bottle of baileys for xmas, its the first ive bought for a few years and its nearly gone , think I'll get a port next, another bottle i buy very occasionally. My favourite tipples are cider and lager normally

There you go, ive lightened the mood already you're welcome

 

[Jameshow]

How was everyones day? I had a burger for lunch.... it was beef, onion and honey with a sprinkling of pepper, topped with a bit of crispy bacon and a slice gouda in a brioche bun ive got a george foreman on site for warm lunches
( we had them last night and i always make a spare for the next day )

I ( last week ) bought a bottle of baileys for xmas, its the first ive bought for a few years and its nearly gone , think I'll get a port next, another bottle i buy very occasionally. My favourite tipples are cider and lager normally

There you go, ive lightened the mood already you're welcome

Did you sort your mortgage out btw?!

 

[baldkev]

Did you sort your mortgage out btw?!

We are going for 3 year fixed and i put a deposit on the digger, should get it in the next week or so

 

[J-G]

Hmmm... How often did the presenter refer to 'Maths' ? (I lost count) 'Congruence' is a geometric/mathematical term, and he used that a great deal as well.

I'll concede that he didn't use 'arithmetic' or 'numbers'

 

[Tom K]

Hmmm... How often did the presenter refer to 'Maths' ? (I lost count) 'Congruence' is a geometric/mathematical term, and he used that a great deal as well.

I'll concede that he didn't use 'arithmetic' or 'numbers'

Well the presenter is a teacher of maths so he is going to use those references. It’s entirely possible that the person who first discovered the method would have never heard the terms mathematics or geometry. It could be argued that as soon as there are numbers applied it becomes at least arithmetic and that even without measurement becoming involved the division of an object into 3 is at least that. I think the original posters problem didn’t need any more applied mathematical theory but more some simple measurement to find the parameters that needed to be fixed and the drawing of a cross section to gauge the preferred angles.

 

[J-G]

Well the presenter is a teacher of maths so he is going to use those references. It’s entirely possible that the person who first discovered the method would have never heard the terms mathematics or geometry. It could be argued that as soon as there are numbers applied it becomes at least arithmetic and that even without measurement becoming involved the division of an object into 3 is at least that. I think the original posters problem didn’t need any more applied mathematical theory but more some simple measurement to find the parameters that needed to be fixed and the drawing of a cross section to gauge the preferred angles.

My point was/is that Jacob & Adam insist that Geometry is not Maths but that video shows that 'Maths is everywhere'.

 

[Jacob]

.....I think the original posters problem didn’t need any more applied mathematical theory but more some simple measurement to find the parameters that needed to be fixed

Didn't even need measurements; could just hold the item against blank and draw directly from it.

and the drawing of a cross section to gauge the preferred angles.

Not needed, simpler and easier without.