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Volvo knuckle enhancements for more funsies

Posted by Robert Culbertson 
Robert Culbertson
Robert Culbertson
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Volvo knuckle enhancements for more funsies
May 10, 2015 01:09PM
From looking at the parts after the failure at OTR, the thin section on the outboard side was the initial point of failure. The area is thinner than normal because the holes were initially drilled for camber bolts. The area that broke was ~0.150in thick, I'm not sure what the thickness is normally. Not all of the goosenecks on JVAB suspension have this issue, but it's worth checking and reinforcing if necessary. The quick solution I came up with (for the knuckle that didn't break) was to add more material. I used 2 layers 3/16in steel flat bar welded to the outboard side of the gooseneck. This added a total of 3/8in of material in the area of failure, and it ties in nicely with the Volvo knuckle.

For the side that broke, I got bored at work and spent some time with a lathe and mill. This resulted in the Super Beechin Plus strut-to-knuckle mounts. These press (lightly) into the Volvo knuckle and are secured by a weld bead around the top (peened afterwards to help with fatigue), and reinforced by a simple 1/4in plate gusset to make me feel better. The SBP S-T-K also locates the lower ball joint cup as well. This does move the strut inboard a bit and offers much more tire-to-strut clearance resulting in camber being able to actually go to zero or negative numbers.



Edited 1 time(s). Last edit at 05/10/2015 01:10PM by Robert Culbertson.
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Attachments:
open | download - JVAB, original failure.jpg (41.3 KB)
JVAB, original failure.jpg
open | download - JVAB, modified.jpg (36.9 KB)
JVAB, modified.jpg
open | download - JVAB, reinforced.jpg (39.4 KB)
JVAB, reinforced.jpg
open | download - super beechin plus (3).jpg (55.7 KB)
super beechin plus (3).jpg
open | download - super beechin plus (2).jpg (37.4 KB)
super beechin plus (2).jpg
open | download - super beechin plus.jpg (47.4 KB)
super beechin plus.jpg
john vanlandingham
John Vanlandingham
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Re: Volvo knuckle enhancements for more funsies
May 10, 2015 03:08PM
OK, Culbertson, you need to learn about mitigating and transferring stresses..


Nice design and all on the replacement part---as I said on the phone it was the instantly obvious way for doing that idea years ago---and rejected almost as fast from a wastage of material and excessive mill time POV... and from the clear lack of need for the part where it plugs in the be solid, and welded 360* (bearing in mind that OEM Volvos are not even welded into the knuckle...The tube is inserted and the ID is 'rolled" or "upset" and that's it....obviously no need for solid and 360 weld.)

Now go look at any steering head on any bike after maybe 1959* and you'll see NOBODY (that wants to have the steering head stay on the bike) puts gussets on centerline of something seeing force....they put gussets on each side
Not O- but OE without the middle one...

Not my opinion, although I never did gussets on anything that way, it was a guy whose business card read SENIOR STRESS ANALYST who worked for Boeing...I'd call him SeƱor Stress Analyst..

The diuscussion was on guessts on tube structures like bike frames and roll cages, but the principle is the same...
On sides, not center-line.



John Vanlandingham
Sleezattle, WA, USA

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Robert Culbertson
Robert Culbertson
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Location: Portland , Or
Join Date: 08/15/2010
Age: Party Animal
Posts: 1,210

Rally Car:
MK2 VW GTI



Re: Volvo knuckle enhancements for more funsies
May 10, 2015 04:52PM
Gusset in the centerline of a tube is a no-no. Centerline of a 1in wide piece of steel that's 2in in depth, not an issue at all. It's not a stress mitigation issue, but to increase stiffness a wee bit.

I don't even have a business card... It would read something equally as impressive I'm sure.

Thanks for the lecture on stress analysis....
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john vanlandingham
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Re: Volvo knuckle enhancements for more funsies
May 10, 2015 05:24PM
Quote
Robert Culbertson
Gusset in the centerline of a tube is a no-no. Centerline of a 1in wide piece of steel that's 2in in depth, not an issue at all. It's not a stress mitigation issue, but to increase stiffness a wee bit.

I don't even have a business card... It would read something equally as impressive I'm sure.

Thanks for the lecture on stress analysis....

Knew you'd have an answer to dismiss it..

Yeah probably not an important deal on a 1" thick thing... but still why NOT do it with 2?


And knew you'd be dismissive of a guy with more years doing analysis of parts stressed orders of magnitude more and consequences far more potentially catastrophic than little car shit, than you've been on earth..
What the fuck could know know?

Wasn't a lesson, just trying to point out something in terms you might understand.

Sorry.



John Vanlandingham
Sleezattle, WA, USA

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www.rallyrace.net/jvab
CALL +1 206 431-9696
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Robert Culbertson
Robert Culbertson
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Location: Portland , Or
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MK2 VW GTI



Re: Volvo knuckle enhancements for more funsies
May 10, 2015 06:25PM
Why not with two? Because it would be impossible to weld it on, unless you like half welded garbage. The real proper way to do it is a box-section. That would be easy peasy with a section of square tubing. Didn't have any at the shop. It's hard to find anything thinner than 1in plate at work.

I'm also not trying to be dismissive or start any asada if you know what I mean. Two is better in theory, but theory isn't always possible.
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john vanlandingham
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Re: Volvo knuckle enhancements for more funsies
May 10, 2015 07:19PM
Quote
Robert Culbertson
Why not with two? Because it would be impossible to weld it on, unless you like half welded garbage. The real proper way to do it is a box-section. That would be easy peasy with a section of square tubing. Didn't have any at the shop. It's hard to find anything thinner than 1in plate at work.

I'm also not trying to be dismissive or start any asada if you know what I mean. Two is better in theory, but theory isn't always possible.

mostly what I'm trying to do is teach others... You're going to do what you're going to do because you thought of the idea and that's it..
But others maybe slower thinking see stuff like "half welded"....and think "Oh dear"

But then if you think about it many things are welded on one side only...

Like roll bar joints...

Gussets on cages or frames

Every "ear" on every strut made.


And a box section (presumably cut off like a wedge) like you suggested... ...Only get to one side on that...so that "must be" "half welded garbage"...

Your choice of words LOOKS dismissive even if your intent may not be...it looks contemptuous...
And then you suggest something just the same..

What I'm saying is slow down..You are not near as smart as you think, and I'm not half as dumb as you think..
I don't think there's one part I have made or one suggestion that you don't instantly have a comment or suggestion on how it should be done...

You're very young so like every young guy, when you think of something (like the make the gooseneck thang outta round bar and carve it up in the mill) you naturally think you've discovered something...., and you think its a great idea...

And then you see the time it takes to do one..

And I'm making 20-40 things at a time...different requirements..

Not everybody has a bottomless check-book..



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.
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Robert Culbertson
Robert Culbertson
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Location: Portland , Or
Join Date: 08/15/2010
Age: Party Animal
Posts: 1,210

Rally Car:
MK2 VW GTI



Re: Volvo knuckle enhancements for more funsies
May 10, 2015 07:35PM
All good advice, and well taken.

I do end up saying things that a newb would read and get confused about. Like the box section only being welded on one side. This is true. I would use something thinner (1/8in) and get full penetration in one pass. That's how my mind thought about that.

I do tend to get a little too fancy at times as well. That's just were my background is.
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john vanlandingham
John Vanlandingham
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Re: Volvo knuckle enhancements for more funsies
May 10, 2015 07:52PM
Quote
Robert Culbertson
All good advice, and well taken.

I do end up saying things that a newb would read and get confused about. Like the box section only being welded on one side. This is true. I would use something thinner (1/8in) and get full penetration in one pass. That's how my mind thought about that.

I do tend to get a little too fancy at times as well. That's just were my background is.

And I would lean toward 2 at least 5/16s- 3/8 and beveled for good root penetration...

And I know--from oh say 40 years ago welding many things--lots of things, like sand and gravel truck bodies on the one hand and motorcycle frames on the other that we don't always weld both sides...
And its no problem...

That's why I take issue with what and HOW you say things and the implied meaning of the words...... Your implied message is "I can do it better this way"...

Guess what. I can do things better too....but there's a price...always mindful of price...and if 2 hours more mill time is going to equal any measurable or noticeable difference...

Always the price thing...

Beginner car guys budgets are not what hard core bike guys, particularly guys going for custom frames budgets are...



John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
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