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-   -   ball joint tapered cones (https://www.rx7club.com/race-car-tech-103/ball-joint-tapered-cones-1058123/)

GrossPolluter 02-25-14 11:09 PM

ball joint tapered cones
 
I forgot the technical name of those tapered cones people use to bolt up spherical bearings into spindles. Anyone know where to buy them? I wonder if its the same fitment as another application. Anyone know? I'm interested in fabricating front lower spherical bearings.

j9fd3s 02-26-14 11:17 AM

you might shoot Alex@battleversion an email. the FC BTW doesn't use a tapered ball joint in the front

GrossPolluter 02-26-14 05:46 PM


Originally Posted by j9fd3s (Post 11687588)
you might shoot Alex@battleversion an email. the FC BTW doesn't use a tapered ball joint in the front

I just saw that this morning. now I have to think of a design

peejay 03-01-14 10:55 AM

IIRC the thing to to is aircraft grade 18mm bolt with the head cut off and a channel cut into it so you can clamp it in the upright.

At least, I THINK it was 18mm. The common sizes for this style ball joint are 17, 18, and 19mm, and I play with a bunch of VW stuff and they're similar but different and had a couple sizes over the years.

eage8 03-01-14 03:13 PM


Originally Posted by peejay (Post 11689490)
IIRC the thing to to is aircraft grade 18mm bolt with the head cut off and a channel cut into it so you can clamp it in the upright.

At least, I THINK it was 18mm. The common sizes for this style ball joint are 17, 18, and 19mm, and I play with a bunch of VW stuff and they're similar but different and had a couple sizes over the years.

Rx7s are 18mm (I've measured them.). From my research VWs use 15, 17, and 19mm pinch joints. So that's no help.

Your post did give me an idea though. I'll post pictures tomorrow night :-)

peejay 03-01-14 05:51 PM

Andrew Havas's rally car used aircraft bolts in the uprights in exactly the manner I described, and fabricated control arms.

There was a somewhat infamous picture of when he rolled at a rally after he broke his wrist from driving one-handed (broken trans - had to hold it in gear) and both control arms were pulled apart but the spherical bearings were still attached to the uprights. So the method is clearly strong enough :)

Don49 03-02-14 07:16 AM

AWR Racing has a roll center correction kit that uses the early a arms with the bolt in ball joint. I just installed the kit on my 7. After looking at it, someone with good fab skills could make the same set up with a little machine work.

abeomid 03-02-14 10:13 AM


Originally Posted by Don49 (Post 11689960)
AWR Racing has a roll center correction kit that uses the early a arms with the bolt in ball joint. I just installed the kit on my 7. After looking at it, someone with good fab skills could make the same set up with a little machine work.

Those ball joints are nice. However do check them often for signs for crack and fatigue. Not sure if Tony ever changed the design/material. But we had a couple fail on us and looking at the failure point it was tail-tail signs of fatigue similar to the attached picture:

http://technology.open.ac.uk/materia...s_fat/fig1.png

eage8 03-02-14 10:54 AM

^yup, you can see the line in mine when it broke:

https://lh5.googleusercontent.com/-r..._140129262.jpg

the pin broke right at the pinch joint.

the reason is 2 fold:
1 - it's recessed all around like the stock pin is so the smallest diameter is only 15mm.
2 - there is nothing to tighten the spacer to the knuckle, so it's not supporting the pin at all to prevent more side loads.

Don49 03-02-14 02:03 PM

Apparently the design has been changed as there is now a step that seats at the base of the upright. Also, I don't know if it was done before, but they are now heat treated.

eage8 03-02-14 11:01 PM


Originally Posted by peejay (Post 11689707)
Andrew Havas's rally car used aircraft bolts in the uprights in exactly the manner I described, and fabricated control arms.

There was a somewhat infamous picture of when he rolled at a rally after he broke his wrist from driving one-handed (broken trans - had to hold it in gear) and both control arms were pulled apart but the spherical bearings were still attached to the uprights. So the method is clearly strong enough :)

Finished my modded AWR ball joints:

https://lh4.googleusercontent.com/-F..._233610195.jpg

I drilled out the pinch area to 3/4" (19mm) (which took way longer than I thought it would for just 1mm larger). I notched a 3/4" grade 8 bolt and hammered it through the top and pinched it in place. :icon_tup:

the bearing spacers and bolt length need tweaking...

peejay 03-03-14 06:46 PM

I was considering boring them out to 19mm so I can use GM N-body control arms. The ones for, say, an '05 Malibu or G6 are about the same as FC but longer, and the rear bushing is more conducive to the kind of geometry alterations I want to make.

Y'know, I DO have a spare set of uprights...

GrossPolluter 03-03-14 09:58 PM


Originally Posted by eage8 (Post 11690442)
Finished my modded AWR ball joints:

https://lh4.googleusercontent.com/-F..._233610195.jpg

I drilled out the pinch area to 3/4" (19mm) (which took way longer than I thought it would for just 1mm larger). I notched a 3/4" grade 8 bolt and hammered it through the top and pinched it in place. :icon_tup:

the bearing spacers and bolt length need tweaking...

Nice work! That is what I was thinking about doing also.
how much did you space it out compared with stock?
Are you using a snap ring to hold the bearing in place?

eage8 03-04-14 09:42 AM


Originally Posted by GrossPolluter (Post 11691075)
Nice work! That is what I was thinking about doing also.
how much did you space it out compared with stock?
Are you using a snap ring to hold the bearing in place?

the AWRs were spaced out 1", in the picture that is currently 0.75"... I haven't decided what I'm going to space it out yet. we'll see. I'll probably measure some stuff to find out where my roll center actually is first.

the actual ball joints are AWR units and yes they have snap rings in the containers, but you have to be careful how you clock them or they limit the articulation which sucks. your best bet is to put them towards the front of the car (caster tilts the strut back)

They're using a QA1 WPB12T bearing.

GrossPolluter 03-04-14 09:51 AM

!
 

Originally Posted by eage8 (Post 11691324)
the AWRs were spaced out 1", in the picture that is currently 0.75"... I haven't decided what I'm going to space it out yet. we'll see. I'll probably measure some stuff to find out where my roll center actually is first.

the actual ball joints are AWR units and yes they have snap rings in the containers, but you have to be careful how you clock them or they limit the articulation which sucks. your best bet is to put them towards the front of the car (caster tilts the strut back)

They're using a QA1 WPB12T bearing.

Cool, thanks! Do you have a picture of the limiting articulation. Is the bearing more towards one side when sitting?

At first I was thinking of a design like that, but now I am curious on a threaded length to adjust length and adjusting the position of the bearing. Hmmmmmm

eage8 03-04-14 09:59 AM


Originally Posted by GrossPolluter (Post 11691332)
Cool, thanks! Do you have a picture of the limiting articulation. Is the bearing more towards one side when sitting?

At first I was thinking of a design like that, but now I am curious on a threaded length to adjust length and adjusting the position of the bearing. Hmmmmmm

Here is a picture at full droop with the original AWR everything, you can see that the bearing is at the end of it's articulation (I think it's actually the limiting factor in droop). you can fix this by either bending the ball joint more or modifying the ball joint for more articulation
https://lh3.googleusercontent.com/-G...0/IMAG2027.jpg

I've already ordered new bearing spacers that I'm going to modify and see how they work, I'll keep my build thread updated.

are you talking about adjusting the length of the control arm? that's going to be pretty hard without putting some serious bending loads through a rod end.

GrossPolluter 03-04-14 10:12 AM

have you checked with the car on the ground, 4 post lift, or with suspension suspension raised to your ride height? I can't see the front to back lean, but your saying more positive caster would allow more movement as well?

Also, I noticed your ball joint is mounting on top of the control arm. Mine are at the bottom

eage8 03-04-14 10:34 AM


Originally Posted by GrossPolluter (Post 11691349)
have you checked with the car on the ground, 4 post lift, or with suspension suspension raised to your ride height? I can't see the front to back lean, but your saying more positive caster would allow more movement as well?

Also, I noticed your ball joint is mounting on top of the control arm. Mine are at the bottom

no... positive caster actually inhibits movement a little unless you have the ball joint twisted slightly backwards....

I was saying you should put the circlip holes towards the front (on top, towards the back on the bottom) because it's less likely to interfere with things...


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