My friend and I are gonna build a cage for my F4, He built several for his and other buddies gixxers. Anyways he said to get chrome moly in 3/4 to 1" but doesnt remember the wall diameter. So what have some of you guys used?

 

.156












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.098342

 

dont waste your time with chromoly. get some 1" steel tube with a .125 wall. WAAAYYYY cheaper. dont get cold rolled either. another waste of money.

 

chromoly will hold up better and is lighter, however it doesn't absorb impacts as well as steel since it's not as soft, if you do go chromoly make sure you use some soft washers in between the cage and your frame. Steel will have less chance of damaging your frame however the cage won't hold up to as many impacts. If the bike is going to see a lot of abuse go chromoly, in fact i'd go chromoly either way.

 

if youre going to use .156 wall, that cage is going to weigh 30 plus lbs. use steel, forget the choromoly. if you get a .120 wall steel cage, its going to be way lighter & will hold up to the same impact a chromoly cage will hold up to. i do this for a living, ive seen the diference & there really isnt one. go with whats cheaper. the only reason to go to chromoly with a .156 wall is if you have a 7' tube that is going to go under the bike- which is why it works for FI.

 

What about 1" Schedule 40 black pipe? I had some given to me. That should work for awhile right?

 

i think schedule 40 is the same as .120 wall, but im not 100% sure on this. it will work fine if it is. the material isnt what makes a cage work. its the design of the cage. obviously if you use aluminum the cage isnt going to work all that well, but if youre having trouble deciding on a hard metal, use whats cheapest. youre going to break it eventually anyways.

 

Considering that the tensil strength of chromoly is two to three times that of mild steel, i think you can get away with using less than .156 tubing, you can infact get away with using an even thinner walled tubbing while still maintaning more strenth hense the lighter weight. The only problem with chromoly is the fact that it's harder to work than regular steel which turns most people away from it along with the fact that it shouldn't be mig welded. Other downside is what i said the fact that it's more brittle, i would certainly run a slider so the steel didn't take the immediate impact. If not welded properly the welds tend to crack on chromoly under hard impacts.

 

thats why i say just use steel. the cage is going to take an impact, not the slider. the slider may stop it from going over, but the cage itself is what takes the impact. in order to truely get the benefits of chromoly, you have to heat the metal before welding it anyways, & who has an oven lying around that will fit a cage anyways. you cant go wrong with steel, or at least its very hard.

FI migs up their cages too, so i think you can mig chromoly, but i wouldnt know myself, never tried it.

i do have to agree with .156 being over kill too. i started making cages with it, but its not worth it. i make them with .120 wall, whether its steel or cm.

 

You can mig weld it however it's much much much better to tig it. If you mig chromoly the weld will be weaker than the surrounding metal and the weld will give before the metal, in that case you may as well run mild steel because you're only as strong as your weakest link. Other reason tig is stronger is becasue with mig you get a different heat range throughout the weld, to cold at the beginning and usually to hot towards the end of the bead, this leads to inconsistent strength throughout the weld. When you tig it you have the correct heat range throughout the weld which obviously leads to a stronger weld with less inconsistances. Also when dealing with tubing you don't really have to worry about heating it much, though it's obviously not a bad idea to remove any residual moisture, but you can get away without having to heat it much before you weld it. Sliders actually will help reduce the intial blow, the derlin is much more elastic than the moly and will absorb some of the intial jolt which is what you have to worry about with moly.

 

Also as far as preheating bigger items look into infared heat lamps, i picked up a set up for just over a grand that can take care of pretty much anything.

 

totally agree with everything you said on the above post. thats why i NEVER mig anything, plus it looks like ****. i dont ever heat it up, i just weld it with steel & it works for what im doing. you have to be building race cars & planes in order to get that much into it. if i ever get into that stuff, i will definitly check out the heat lamps, thats a good idea

 

remember the larger diameter of the pipe, the more resistant it is to bend
ie.. a 1.5 inch pipe is stonger than a thicker 1 inch diameter pipe ,
even thou the pipe is thinner it is stronger

 

1.05 X .125 wall HSS tubing is 1.23 pounds/foot. Call the metal supermarkets or whoever is local, should be about $1.00/foot for retail.

 

out here i pay $1.38/ft for 1 1/4" .120 wall. and $1.07/ft for 1" .120 wall.

 

Go with 1in electric weld 120' wall.

 

Why not just use some electrical conduit(sp)