frame material, how thin is too thin?

[azarak]

Building a fun kart that will see a lot of off road/very little pavement driving. I have some 1" square tubing that I had intended to use but its only 16 guage steel. Frame will be pretty basic ladder,live axle,no suspension.
Any one think I should buy some thicker wall tubes, or will what I have be OK?
New to karts first frame build so I'm a little cautious.

 

[azarak]

anybody?

 

[itsid]

depends on the design of the kart.
a basic ladder frame has two members lengthwise.

warning that's just an idea/oppinion.. no science or wisdom involved
But I'd say lay one piece of tube onto two bricks (the desired length of your kart apart) and stand on it.
if it doesn't flex you should be good;
if it does you may very well run into problems without proper bracing.
if it breaks or bends.. well forget about it

Theory: small bumbs can easily equal 2-3Gs that means twice to three times your own weight has to be supported.

'sid

 

[ampedtech]

16ga = 0.0598 black pipe schedule 40 3/4" wall is 0.113"

Of course you could use the sq 1" x 16ga if in your design you reinforced the tube, but if you like your butt (hope that's not too racy) use 3/4" black pipe.

You may even consider using 1" black pipe. The wall on 1" is 0.113.

Black pipe because you don't want to weld on galvanizing and, it's cheep.

Home Depot 3/4" $15.22 for 10'

A lot of consideration should be given as to the max weight of a driver and the terrain your kart will on.

Further, round, (pipe) is better cause it handles stress (bumps, vibration and flexing) more uniformly compared to square. So less engineering (design) needs to be done.

You also need to consider attaching your chosen building material. If you plan to weld, 16ga might be a challenge as it is thin. Drilling holes and using bolts might also be difficult because even a 1/4*20 bolt through 2 walls of the sq has the ability to squash that tube.

I could go on and on. If you want me to I will.

 

[MidNightIllusions]

Depending on your design the 16 ga will be fine. That's all that some karts are made from. It's just the engineering behind it.

1" black pipe is over kill. It'll be a heavy slug. Need a 10 hp to move the pig lmao.

But you should draw an idea and let us have a look and maybe give you the best advice.

 

[bshinn]

Depends on the material. Is it mild steel, or 4130?

 

[azarak]

Its home depot 1" square, so no in the 4130.
I'm new to welding so I'm using square rather than round for this first project. It is thin yes, but so far I haven't blown through any joints.
I can tell it will need reinforcement and am planning on a "double decker" ladder frame.
I have tried to post pics and keep getting an "invalid file" when I paste from my photo bucket acct. If I figure out how I'll post progress so far.

 

[azarak]

[/URL][/IMG]

 

[azarak]

Well that didn't work............

 

[mckutzy]

Post the link of the photo.

 

[azarak]

[/URL][/IMG]

 

[azarak]

Finally!
I'll post a photo of progress so far in a few.
(Took the wife to moto go a couple of weeks ago, it was a blast! Sorry for the off topic photo)

 

[azarak]

The 16g tubing is proving to be too thin for my limited welding capabilities. I think I could reinforce the frame enough to last a while, but the idea I have for the front axle is going to be a weak link. Not to mention overly complicated to make "safe".
Scrapping this frame and searching for thicker walled tubing.
(Don't look too close at my welds!)

 

[rocketkart]

look's good. i hade made one like that with the same tubing and it held up me at 225 lbs. get you some of plugs for the tuping. http://www.ebay.com/itm/Square-Plas...509?pt=LH_DefaultDomain_0&hash=item3a819a1efd

 

[azarak]

thanks for the feedback rocketkart. i found some 1" 11g tubing that i think might be easier for me to learn on.
i'm no welder and only about half my beads look ok. also had a lot of issues mating the thicker bearing plates to the thin walled tube.
this is only my 2nd welding project and i just dont think i have the skill to do metal this thin.
first project was a cart for my welder (hobart handler 140), i used 1/8" angle and produced some pretty good welds so i think i will be better off with thicker wall tubes.
i'll cut this one up and keep the tubing for practice/other projects

 

[andrewmacc]

We're using 1"x.100" wall round tubing, it still has some bounce to it but it seems very sturdy. It's a little heavy for my liking for a gokart, but I come from a background where 1/4" was absolute minimum for anything.. so 16 gauge always concerns me but hey, I guess it works. It's a mix, you can use thin walled tubing and require more bracing, or thicker tubing and only brace where necessary.

I ran the calculator earlier and our exact specs of 1.050"x.100" come up as 1.0135lbs per foot, so even if you use 44 feet of tubing in your frame, the frame itself weighs 44.6lbs. I can live with that.

Although jealously I admit 16 gauge would only weigh 28.5lbs for an equivalent amount.