Audi Control Arms

OK - I've finalized the design I'd like to use on the control arms for the Audsterator.

Basically use a chromolly tube design - but forgo using heim rod ends to attach the control arm to the sub-frame. Instead take a piece of chromolly tube that fits the stock bushings. Press those in and tig weld a stud to the outside of the tube. Basically now I'll have an adjustable bushing based rod end.

I found a site that has weldable threaded studs (10/20 cold rolled steel) and threaded tube ends (bully chromolly).

They seem to be farging expen$$ive - like $14 ea for studs and tube adapters

http://www.ballisticfabrication.com/

The question is:
a) is the cold rolled steel going to be strong enough as a stud
b) is this stuff over priced for what it is?
-- if so, where would you source it
c) does chromolly tube exactly 37mm I.D. exist?
-- does my idea of just pressing stock bushings in there fly?

Thanks !!

Vittorio-



Edited 1 time(s). Last edit at 09/11/2007 12:44PM by vbares.

vbares Wrote:
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> The question is:
> a) is the cold rolled steel going to be strong
> enough as a stud

Yes, the 1020 CRS will be fine. Unless you plan on heat treating the arms when you're done the chromoly will only get you a weld that fails first instead of bending the threaded stud. If you decide to go chromoly TIG weld them with Weldmold 880 filler metal or the generic equivalent. That will get you the maximum strength and a ductile weld with out heat treating. If you are going to TIG them with S70 filler or MIG weld them the chromoly is just wasted money.


> b) is this stuff over priced for what it is?
> -- if so, where would you source it

Not really but you can save a buck a piece on the tube adapters here. www.polyperformance.com Look under the suspension joints page.


> c) does chromolly tube exactly 37mm I.D. exist?
> -- does my idea of just pressing stock bushings in
> there fly?

Not unless you want a mill run of at least 5000lbs. Just get someone with a lathe to bore a piece of tube to size for you. Then you can control the pre-load when you press in the bushings.



Tim

Thanks Tim!

Is there a better material to build the control arms with than chromolly?

You tried sending dave (OWDLVR) an email? He'd probably be able to make some recommendations.

I'll give him a shout.

Mountain biker, rally driver and metalurgist? Wow!

Thanks!

vbares Wrote:
-------------------------------------------------------
> Thanks Tim!
>
> Is there a better material to build the control
> arms with than chromolly?


Unfortunatly, there is no way to make a generic statement as to the correct material. Using 4130 chromoly tube will give you an extra margin of strength as long as it's welded properly to prevent embrittlement in the weld zone (hence the weldmold 880 so you don't have to normalize the welds). If you need that margin and is it worth the price premium over standard 1018 or 1026 DOM tubing is up to you.

Tim

Vitorio Muchachito mio,
when thinking about material, remember that the standard control arm a cheezy ass weak sheet metal stampings.
Nearly anything will be better than that.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Grazie - this is true, very true...

The guy that's making these, believe it or not, makes high-end bicycles. Lots of experience w/both steel, titanium and TIG. A craftsman and inventor/engineer - I'm confident in his abilities to produce quality. But you are right, sometimes we obsess at what is 'best' when 'good' is already a significant leap forward.

BTW - could you send my parts back to the nudest of the hampshire

vbares Wrote:
-------------------------------------------------------
>
> The guy that's making these, believe it or not,
> makes high-end bicycles. Lots of experience w/both
> steel, titanium and TIG. A craftsman and
> inventor/engineer - I'm confident in his abilities
> to produce quality. But you are right, sometimes
> we obsess at what is 'best' when 'good' is already
> a significant leap forward.

Good deal...I used to weld bicycle frames back in my college days. Who's the builder? I proubably know him. Just don't let him use any bicycle tubes :-) The last thing you need on an Audi is a .020" thick tripple butted Colombus Zona tube...



Tim

LOL!!

Look good - light - and bend like soggy pretzels

George Reynolds, Derry NH

Son is heavy into BMX and dirt jump - so there is some dirt in that blood line