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Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 19:42
by rodp
Sorry for the heading but wanted to attract attention
The question I have is, I need to drill five holes on a 4.5" pcd, how far apart do the holes need to be. I have it at 2-3/8" (may have been 5/8, not got it here) apart but when scribing it they don't quite match up.
Can anyone work it out or run it through autocad ? It would be a great help. The fraction it's out wouldn't really matter but I like it smack on if possible.
All answers greatly appreciated, even the daft ones if the make me laugh.
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 20:32
by rodp
Well, I'm quite surprised no-one's jumped in with the answer
I thought I was the only one on here with age related fading faculties ...................seems not
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 20:42
by phoenix
Rod,
I make it 2.827"
Circumference of the 4.5" circle is 4.5 x 3.14159 = 14.137"
Distance between holes is 14.137/5 = 2.827"
Cheers
Bruce
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 21:01
by chas
If it's wrong for straight line measurements, blame the website, not me.
Load of rubbish crappy useless web calculator now removed to avoid confusion
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 21:09
by phoenix
Well,
It looks like my maths is still s**t!!
Honest guv, if it was a 4.5" diameter pipe and you wanted 5 holes drilled around the circumference at equal distances, then the distance between the holes would be 2.827"
Cheers
Bruce
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 21:12
by chas
It is Bruce, but that's on the arc.
The link gives it in a straight line, I hope.
Quick edit;
By saying "it is", I meant it is the figure you mention, not, yes your maths is shit
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 21:45
by terry1001
chas wrote:It is Bruce, but that's on the arc.
The link gives it in a straight line, I hope.
Quick edit;
By saying "it is", I meant it is the figure you mention, not, yes your maths is shit
I think you're both wrong, I calculate the c-c distance to be 2.645", (I hope I'm right)
Chas, in your diagram angles B and C should be equal at 54 degrees (54 + 54 + 72 = 180)
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 21:55
by chas
Just worked it out without that silly calculator thing and you're right.
I put in side B, side C and the angle of A (light coloured figures) so where the hell those other figures came from is anyones guess.
Possible irregular versus Isosceles calculator
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 22:20
by chas
The correct calculator, I think.
Re: Clever person needed, dumb asses need not apply
Posted: 18 Jun 2013, 22:35
by Gloop
67.18mm
