It would have to be a strip as thick as the half hole to have the same strength!

Holes don't add strength. A hole is a circular absence of material, it is impossible for an absence of something to add strength. A circle is a naturally strong shape, but a circle is the strip of material that surrounds a hole.

A swaged hole can add rigidity to a thin panel, not from the hole but from the swage adding depth to something that would otherwise be a very 2 dimensional.

@Russ, I could do with a couple of swaged holes in something I'm making at the moment, any chance you could put a couple in the post for me!

First things first,
Hi there, Old-Nail.

Back to the discussion, or the 'argifying', depending on your point of view...

An arch form is useful when the construction materials available are strong in compression but weak in tension, which is why most arch bridges are constructed from stone, cast iron, bricks or mass concrete.

< http://en.wikipedia.org/wiki/Arch >

Any holes formed in the structure of an aircraft are there solely to reduce the dead weight of the craft and their effect on increasing the stresses in the part from which material has been removed must always be considered very carefully.
Invariably, material will only be removed close to the neutral axis of a section, bearing in mind that's where stresses are usually lower.

< http://rgl.faa.gov/Regulatory_and_Guida ... er%201.pdf >

In the case of a vehicle chassis, torsion in the main rails is also applied to its crossmembers, so drilling or laser cutting fancy patterns in the latter isn't the best of ideas.

ken

Hi Ken. It's argufying, by the way, tut tut man your standards are slipping.
Just kidding mate, I think the key is in the direction the stress is applied then yes?



But a hole - is a circle, which is therefore a naturally strong shape? Why can't it work in the same way that a sheet of metal is less rigid than a corrugated one? Why aren't H vans smooth if it makes no difference?

Yeah that'd be luck.

I'm not really interested in whether the holes make the car stronger or weaker than before. although the answer is they make it weaker. A nice set of swaged holes looks the bollocks. I don't even need holes where I'm putting them, but it's basically one of those things I've always wanted and I've saved my pennies up and bought one and by jingo I'm going to use it wherever I can. In fact I'm going to order some more in different sizes now. First thing to be done is the bonnet and front bumper of my 2cv. Then the AX grasstrack car and then anything I can find that I can wang a hole in.

It makes holes look like this:







Joolz, you could make one of these tools easily, but I'd be more than willing to send you some holes. Postage should be fairly cheap...

I fully expect that aliens will either land, (or possibly the government will admit to them already having done so) and turn our accepted knowledge of stuff like this on it's head. For example why must a vessel have integral strength? Couldn't the interior be pressurised to give even the lightest material external rigidity?

Perhaps that's why I like this forum. For every member that seeks, another just likes holes.

Holes are important. We've all sucked a Polo mint and relished the flavour. But compared with other mints. which have no hole. there was always something lacking i.e. the hole.

So a few years ago Polo tried selling just the holes - I still have a pack which are guaranteed to increase in value - a sure fire 20th century antique investment. The holes have just the same flavour without the wasted space in packaging.

And they represent pure strength with no swages.

So there you go - they are extra strong mints then.

As a spotty teanager Polo was.....

POLO - Pants Off Legs Open


Just thought I would share that with you all on a Friday evening and shatter any illusion that Old Nail thought the level of conversation had been much above the gutter in his absence/absibthe !