type of alloy for subframe top mount?

[xa-mont]

hey guys,

Just after some advice of what alloy i should use for my rear subframe top mount? It needs to accept a bolt (so hold a thread) and will be welded to the cast alloy CBR subframe.

Cheers,
Trav

[latheboy]

What does it look like, ei: will it be folded?

The material needs to be 1.5 times thicker than the thread Ø

You could get it laser cut and folded in 3mm and have a clinch nut put in or use a nutsert for the thread.

[xa-mont]

it's probably going to be more of a billet type jobby, not a sheet. Just as a super quick scetch this is what it will look like.

http://i29.photobucket.com/albums/c287/xacoupe/T%20bike/bracket.jpg

I'll take a pic or 2 today of how it needs to attach to the subframe (in case there is a better/easier way to do it)

[xa-mont]

here's a more accurate depiction of how it will go.

http://i29.photobucket.com/albums/c287/xacoupe/T bike/bracketright.jpg
http://i29.photobucket.com/albums/c287/xacoupe/T bike/brackettop.jpg

[latheboy]

I'd use 5083 or 6061, but that it cause i have both materials in stock :)

[xa-mont]

how difficult would either of those 2 alloys be to chop up with simple tools (grinder/files/drills etc) and will either weld to the cast easier?

[latheboy]

Not hard but fuck that would be alot of work.

I don't remember welding 5083, i may have but not sure.
6061 will weld really nice, pushy frames are made from this.

And i'm gonna sounds really smart like with words here.

Welding 6061 is highly weldable, for example using tungsten inert gas welding (http://www.streetfighters.com.au/wiki/Tungsten_inert_gas_welding) (TIG) or metal inert gas welding (http://www.streetfighters.com.au/wiki/Metal_inert_gas_welding) (MIG). Typically, after welding, the properties near the weld are those of 6061-O, a loss of strength of around 80%. The material can be re-heat-treated to restore -T4 or -T6 temper for the whole piece. After welding, the material can naturally age and restore some of its strength as well. Nevertheless, the Alcoa Structural Handbook recommends the design strength of the material adjacent to the weld to be taken as 11,000 psi without proper heat treatment after the weld. Typical filler material is 4043 or 5356.

These are my words and not ripped off from another site cause i'm like smart and shit ;)

[latheboy]

Here, I just type all this up for you.

http://en.wikipedia.org/wiki/Aluminium_alloy

[xa-mont]

so what you're saying is that it would probably need some heat treatment after welding? or would it probably be fine with the lesser strength?

[xa-mont]

looking at the 6061 article on wikipedia it seems to suggest that T4 would be about 190% the strength of O

[xa-mont]

here is pretty much the shape/dimensions that i need (would probably need tweeking to fit perfectly)

http://i29.photobucket.com/albums/c287/xacoupe/T%20bike/bracket-1.jpg

so the question is, where do i get some 32mm x 30mm x 150mm 6061?

[latheboy]

There is a thing called "the Internet" look up your local Al supplier and ask for 6061 T6...

[EXBEN]

if welding i'd use 5083 as it keeps 95% of it's temper once welded ,whereas 6061 softens considerably .

[latheboy]

Really, cool thanks Ben I'll keep that in mind....

[xa-mont]

yeah Thanks Ben.

I'll try hunt down some 5083

[wackyrider]

Not that easy to get a hold of the 5083 from the couple of calls I made today. At least from our usual suppliers

[probike]

action aluminiun have 6061 and 5083

[xa-mont]

thanks man,

The dude out at action in thomastown (which should be easier to get to than the one you found jules) Said they have some offcuts there for 5083 32mm plate, so i recon that would be the go if i can get the rightish sizes.

[wackyrider]

Sweet.