Aps frame material size

[johnneilson]

If going 4130 be careful of weld technique and the filler rod used.

This material was developed for the aircraft industry many years ago when oxy/acet was common.

Today we weld with much different techniques and filler materials. Plan on doing the torch normalizing after welding.

J

[bak189]

Your "over building".......DOM Mild Steel with .085 to.090 wall ....1 to 1 1/4 is all that is needed....We build road racing sidecars that due to extreme cornering get a lot more stress on the chassis....your just going in a straight line (hopefully)......We have never had any problems using the above.........less material costs.........
No BS stress relieving.......Using a in-line-flusher do bronze torch welding (if you can find someone who knows how to do this type of welding)......Use the KISS system...(Keep it simple stupid)....Good luck on your project

[manta22]

 If you need proper filler rods for welding 4130N, check with Aircraft Spruce.Also, these may be helpful:

http://www.millerwelds.com/resources/articles/Best-Practices-for-GTA-Welding-of-4130-Chrome-Moly-Tubing

http://www.lincolnelectric.com/en-us/support/welding-how-to/pages/chrome-moly-detail.aspx

Regards, Neil  Tucson, AZ

[maj]

Who is your frame guy  Dale ?
i like the dom idea too, put your money into better body shape  or more reliable power rather than exotic materials

 

[zooterincm]

I just made my first run with a special construction bike. the bulk of my frane is 1x2  .062 mild steel. mig welded and in some places brazed. The thing that sticks in my mind is that when an space frame 4130 aircraft crashes you find a bunch of tubes that have all failed at the welds. If you have to make a repair on the lake, mild steel will be your friend. Yes, KISS

[grumm441]

Hey Owen
What motor are you looking to use
G

[Greaseballracing]

Thanks again everyone. So general opinions are mild steel dom tube, good point zooterincm at least I can mig a mild steel frame if something does go wrong. Grumm441 I am running a late model 600cc triumph daytona engine with a turbo to put me in blown class.

[grumm441]

The thing is, unlike every other form of racing, it doesn't need to be light
G

[Greaseballracing]

Very true. Just put the templates in to be bent I have gone with mild steel 25.4x 3.96 mm tube so will be machining a new head stock through the week. Thanks again for the help

[Koncretekid]

Thanks again everyone. So general opinions are mild steel dom tube, good point zooterincm at least I can mig a mild steel frame if something does go wrong. Grumm441 I am running a late model 600cc triumph daytona engine with a turbo to put me in blown class.

Greaseball,
Sorry I'm a little late to respond on this thread, but I wanted to chime in; I've had experience with both 1" x .062"wall 1020 CREW (which broke) as well as chrome moly (which hasn't - - yet!).  Don't let chrome moly scare you away.  As Neil has stated, thin walled normalized Chrome moly tubing does not require pre or post heating, can be welded by oxy-acetylene or TIG, and is at least 25% stronger than mild steel.  The important thing is to either know how to weld or to use a welder who does, but that applies to whatever tubing you choose.  

The design of your chassis is just as important as the material.  I doubt that many on this forum have built a bike with a 10' wheelbase and 200 hp.  You're going to be in 200 mph territory (if I had 200 hp, my bike would be capable of about 236 mph) and your chassis is twice as long as a standard bike which means stresses are going to be doubled as well. Consider showing your design to a structural engineer for ideas, but don't expect any engineer to sign off - - because they probably won't (can't because of their code of ethics which prevents them from designing in a field in which they are not qualified.)  But they may be able to give you some valuable pointers.

Tom

[Greaseballracing]

Thanks Tom, sorry for my late reply I ended up with mild steel 25.4x3.96 and am currently working on the frame. I have a reasonable amount of experience in mig welding (currently work on cell towers and do a lot of fabricating to mount antennas and ancillary equipment) if I can figure out posting pictures from my phone I'll show where I'm at. But your input is very appreciated, especially given the speed I am looking at running. So thanks again. Owen

[Greaseballracing]

Ok try that hopefull there is a photo on here now.

[Sumner]

Very nice  .  Lots of triangulation, should be strong.  Keep posting pictures as you fill it in,

Sumner

[bak189]

Hey, I build a sidecar not 10 feet....but 8 feet....with 250hp (turbo)......not 200mph....but it did go 187mph.....(with 2 people on board)....Mild-steel 1.250x.085 Bronze-Welded (Brazing to you none informed...).......raced it on the salt for 10 years......Now in the National Motorcycle Museum........
It is not broken or cracked and still rolls just fine.....................................................................
PS. Your frame looks great....maybe a little "over built"

[Greaseballracing]

Thanks guys, I'll keep the photos up as it moves forward sumner.
Bak189 that thing sounds like it was fun... And durable. I am generally pretty good at over engineering things, but have gone a bit hard with this one just because of the target speeds. Would much prefer to over engineer this than under engineer it. Mtabike, thanks heaps man