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what material for h.d lwer control arms
Posted: Mon Sep 27, 2004 4:02 pm
by fatassgq
Hey all,
As the title says I was wondering what people use for their heavy duty control arms.
I want to make up some rear lower arms (non adjustable) and thought I would ask what everyone uses. I was under impression that chrome molly 4140 etc is not great as you have to weld it and this is not real good. Can introduce a weak spot.
What have people used for their rig.
Cheers
Brian
Posted: Mon Sep 27, 2004 6:07 pm
by A1
Get some 33.4 x 9.01 seamless tube either cut off your original bush tubes and re -weld back being sure to fit them back on at the angle they are from factory or get some made up to suit ........OVERKILL engineerin sell the bush tubes and they are a perfect fit to press the original (BUT NEW) nissan bushes in..................i just made up a jig on a bench at work to get the angle on the tubes right .............
I reused the original bush tubes with factory bushes for my temp set of arms b4 i went 4 link ..........just cooled them very quickly after each run ....i realise this aint the best scenario but it saved on $35-40 bucks ea of factory bush and it didnt seem to effect the bush too much ......................
Dan
Re: what material for h.d lwer control arms
Posted: Mon Sep 27, 2004 10:53 pm
by bru21
fatassgq wrote:Hey all,
As the title says I was wondering what people use for their heavy duty control arms.
I want to make up some rear lower arms (non adjustable) and thought I would ask what everyone uses. I was under impression that chrome molly 4140 etc is not great as you have to weld it and this is not real good. Can introduce a weak spot.
i know glueing is good but you weld steel mate 
What have people used for their rig.
Cheers
Brian
Posted: Tue Sep 28, 2004 6:27 am
by fatassgq
ha ha
Yep your a funny bastard too! Just don't forget to weld those engine mounts in ya patrol and not glue. Don't want a nice gen 3 falling out on the road for some fella to pick up and put in his. (oh shit thinking out loud again) oj
I was being serious though. I think there is a lot of misinformation out there with everyone wanting chromemoly gear when it is true that welding this stuff is actually very involved and not usually recommended.
jmo though.
I guess this goes back to that old thread about making ya suspension from timber and then gluing together
Posted: Tue Sep 28, 2004 7:24 pm
by awill4x4
What a load of bulltish about it not being advisable to weld Chrome/Moly, we weld it all day at work in the sprintcar chassis' repairs we do and I can tell you it welds much nicer than normal low carbon steel ever will. It can be Mig welded without any problems but Tig is the preferred method mainly because as it's stronger than steel the normal thing is go down in wall thickness to save weight and still get the same or better strength.
Regards Andrew.
Posted: Wed Sep 29, 2004 1:02 am
by bru21
tig is good as the stress inflicted by the welding process is spread over a larger area as it stays hot longer like gas welding. utectic brazing is best as it dosen't effect the parent metals strength as it is not hot enough to heat effect it. mig is ok, although stresses can be concentrated as the weld is quite cold generally but hot locally which creates a stress that hasent relaxed before it cools too rapidly.
that is the theory i read, but we all know theory sucks as you think too much and nothing gets built (but you have many beers, which is good) so its all good i guess
bru
Posted: Wed Sep 29, 2004 7:32 am
by fatassgq
tig is good as the stress inflicted by the welding process is spread over a larger area as it stays hot longer like gas welding. utectic brazing is best as it dosen't effect the parent metals strength as it is not hot enough to heat effect it. mig is ok, although stresses can be concentrated as the weld is quite cold generally but hot locally which creates a stress that hasent relaxed before it cools too rapidly.
that is the theory i read,
Yeah that is what I meant. I know it can be welded. (cause the shit is everywhere) but I had heard that welding with the mig in the backyard kind of thing is not the best thing to do as it can introduce stress/weak points. As with all things engineering though you could prolly get away with it 9/10 times and never have a prob. Not too many people have a tig in the shed...
In this case though(control arms) it is prolly easier to just get a seamless tube/mecaval for example and heat up a bit and weld away.
Cheers
Brian
Posted: Fri Oct 01, 2004 1:30 pm
by turps
Whats wrong with using black steam pipe. Thats what I used for my Panhard Rod and it has worked well.
As for getting the angles right. I planned on just cutting the old arms in half, then slip the right length steam pipe over the top. Then just weld the ends on. I also planned on doing some puddle welds.
When I did the panhard rod. The inside diameter of the steam pipe I used was the same dia as the outside of the std one.
Posted: Fri Oct 01, 2004 3:10 pm
by ludacris
I have heard that cromoly tends to crack were steel wil bend.
Posted: Fri Oct 01, 2004 3:14 pm
by Wendle
32NB schedule 160 - 42.2OD x 6.35 wall
about $80 per stick from onesteel.
Posted: Fri Oct 01, 2004 9:00 pm
by Cheezy4x4
36x16 Carbon bar shit on all the other crap, hi carbon so welds sweet and VG memory so springs back when bent. Also comes in 40X20 better still, have done testing in presses and shits all over most others.
