Square tubing. Much, much easier to work with.
Steve, with a decent notcher and bender, you can lose the "much, much" bit and downgrade to easier
, but in general I'd agree.
Square is cheaper and easier to attach brackets and sheet to, but round has a higher stiffness/weight ratio and is much "sexier", and is available in
more grades.
There is nothing wrong in combining the advantages of both with a mixture of square and round.
There you go!......more questions than answers
The other thing I would add is that welded joints are a lot stronger with round tube than square. Virtually all serious motorsport chassis use a lot
of round tubing. There must be a good reason for this.
With the right tools it isn't that hard to work with round given a bit of practise. I will use a combination of round and square on my project. In
fact I will use as much round as I can for weight savings and because I can get better grade round tubing.
Round tube is stiffer than square tube of the same weight.
Working with round tube is actually easier than with square tube, it just takes a little longer.
It’s much easier to position things on round tube.
Suspension brackets etc will get a better purchase on round tube.
If you’re interested, there’s a page on working with round tube on my site. 
Just in case someone comes directly to this thread, and hasn't read another thread on this forum which mentions square versus round tube, I thought I
should correct the gaff I made here:
Above is what I should have said. I previously stated "round tube is stiffer than square tube of the same nominal dimension".
[Edited on 24/2/03 by Rorty]
Rorty, That tube section is worth reading, I never realized there was software for printing out fishmouth templates, ive always bloody struggled hand finishing them!
Mr. Fluffy:
quote:
I never realized there was software for printing out fishmouth templates, ive always bloody struggled hand finishing them!
Just a thought but I had the problem with the front LOCOST wishbones of making the joints a good fit.
My solution was as follows:
1) Put 1" milling tool into chuck of lathe.
2) Put wishbone tube in jig in tool holder at correct angle to cutter.
3) Cut perfectly fitting joints.
Neat but not quick for one offs - any thoughts.
Cheers,
Phil.
quote:
Originally posted by philgregson
Just a thought but I had the problem with the front LOCOST wishbones of making the joints a good fit.
My solution was as follows:
1) Put 1" milling tool into chuck of lathe.
2) Put wishbone tube in jig in tool holder at correct angle to cutter.
3) Cut perfectly fitting joints.
Neat but not quick for one offs - any thoughts.
Cheers,
Phil.
It never ceases to amaze me how many totally unrelated people can come up with the same invention!
As you say, Alan, those milling notchers usually come with a V block vice on a compound slide. Most of the well-heeled race fabrication shops have
them.
Other types are: the belt sander (with compound slide), the plunging hole saw variety, the die-in-a-press type, and the rotary indexer with gas
axe/plasma profiler type.
Phil, for one offs, your setup sounds spot on. 
Phew, another good idea, Ive got the lathe already, just got to rig up a tube clamper to replace the toolpost....
Im going to end up using round tube for all of my chassis arent I? its inevitable, I can feel the pull of torsional stiffness and plain old sex appeal
is winning against ease of use of square...
Another point about square tube's alleged "ease of use.........try to join square tubes of the same size at compound angles.....very difficult and always a bodge.....with round it's just another fishmouth.....
Quite true Alan. I do agree, round tube does look better than square, but wouldn't be THE deciding factor for me. However, one of the best arguments
for round tube, is indeed, the square-tube-compound-joint!
I don't know how good others are at visualising. I see everything in round tube, and that's half the battle....getting your mind around it.
Mmmmm round tube! 
Just out of curiosity, how much would a half decent tube bender cost, and where do you get them from? I had a look around on the net, and could only
find computer controlled tube benders, great if you want to start an exhaust manifold manufacturing company, not so go if you haven't got bags and
bags of cash to spend on that kinda thing.
Just think, with a tube bender, you could make a lovely chassis like the Robin Hood 
!!
Kingr
Don't know what's available in the UK but I have a Pro-tools 105
http://www.pro-tools.com/mb105.htm
Which cost about $400 with a 1.5" x 6" CLR die...... IIRC.
There must be similar available in Britain I'm sure.
There should be dozens of places in the UK which would stock the average lever/ratchet type bender. I ordered one through a tool shop at the back of
the Quedam carpark in Yeovil years ago (can't remember the name of the shop or street).
I also used to order stuff from Frosts in Rochdale.
If you do find a supplier of benders or the bending dies in the UK, will you please let me know? I'm drawing up a home-made hydraulic bender for
people to use with the plans I sell. The bender is designed to fit standard dies....hopefully the UK ones will be suitable too!
[Edited on 25/1/03 by Rorty]
Well, there's a convenience, I live within spitting distance of Yeovil, so I'll have a look to see if they're still around sometime.
Kingr
I absolutely agree on the comments regarding square-tubing compound junctions. On my project there were only a few, and more than enough to convience myself to avoid square tubing wherever I can. And ditto the weight comment. 1" round compared to 1" square is lighter due to the shorter distance around, 3.14" vs. 4". Unless a panel is to be attached, I avoid them. And finally, yes, sex is involved, round is definitely more attractive.
Ive had my eye on one of these... :-
http://www.northerntooluk.com/product_detail.asp?c1=Metal+Fabrication&prodid=14420E
90 quid...
Not a complicated device, but it's what I'm thinking of getting:
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=15257&ts=35625
Ad says 6 dies, but lists only 5. Think they're missing 1.5"
ATB
Simon
Don't want to your dampen enthusiasm, but that type of bender is only useful for really heavy wall stuff IMO...you will find that 16g wall stuff will
collapse and kink....of course I don't know what you plan to bend, but they are really meant for heavy wall pipe....
Rorty explains it well...
http://www.rorty.vze.com/
in the tube work section.
I couldn't get MrFluffy's link to work, so can't comment.
Simon, as AlanB says, that is totally the wrong tool. It won't bend your tube, it will just fold it!
Only buy a bender if it's for TUBE, not PIPE, as there's a world of difference.
Thanks Alan.
quote:
Originally posted by Alan B
Don't want to your dampen enthusiasm, but that type of bender is only useful for really heavy wall stuff IMO...you will find that 16g wall stuff will collapse and kink....of course I don't know what you plan to bend, but they are really meant for heavy wall pipe....
I've heard of plumbers in the old days using lead shot for filling large dia pipes, but you'd need some pretty good gloves to handle pipe filled with
molten lead!
If you don't fancy bending round tube for your chassis, you could always use donuts. The bloke who spins my wheel halves also spins donuts for my
exhausts, which lets me create some really tight headers that conventional benders can't approach.
