welshboy
|
| posted on 28/8/06 at 07:43 PM |
|
|
wish bones
hi could any one tell me if the steel used to make the wish bones has to be seamless thanks
|
|
|
|
|
andrews_45
|
| posted on 28/8/06 at 07:47 PM |
|
|
I saw this asked a while ago, and iirc it was only for aesthetic reasons
|
|
|
Mark Allanson
|
| posted on 28/8/06 at 08:40 PM |
|
|
Yes, purely aesthetic - you look really ugly with bits of engine sticking out of your skull
Use seamless, there is a really good reason why its more expensive
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
JoelP
|
| posted on 28/8/06 at 08:43 PM |
|
|
the better you design your bones, the further you can push it with weight saving. Using seamless would let you go further down the path of lightness.
|
|
|
Mansfield
|
| posted on 28/8/06 at 09:11 PM |
|
|
quote:
Originally posted by Mark Allanson
Yes, purely aesthetic - you look really ugly with bits of engine sticking out of your skull
LOL
|
|
|
Mark Allanson
|
| posted on 28/8/06 at 09:29 PM |
|
|
quote:
Originally posted by JoelP
the better you design your bones, the further you can push it with weight saving. Using seamless would let you go further down the path of lightness.
You really have to get the design right, I have seen pictures tonight of lower wishbones with totally insupported balljoint mounts, and the
reinforcing plate at 90° to the support tubes.
The owner of these wishbones will die if the SVA doesn't pick up the design 'flaw'
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
Mark Allanson
|
| posted on 28/8/06 at 09:40 PM |
|
|
...I have added the 'optional' safety bits in yellow
 
Rescued attachment kitcar004.jpg
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
zetec7
|
| posted on 28/8/06 at 11:50 PM |
|
|
I used seamless, DOM (drawn-over-mandrel) 25 mm (1" tubing for the lower bones. Didn't add any weight, really, but is very strong. The
steel plate to support the ball joint is 3/16" thick, and the plate under the shock is 1/8" (and curved down to the bottom of the tube, then
welded), It's pretty bling at the moment, but it's to be powder-coated black to match the rest of the bits....
 
Rescued attachment lower bone.jpg
|
|
|
britishtrident
|
| posted on 29/8/06 at 06:41 AM |
|
|
To be honest I would advise buying in the wishbones as I and many on the list have experienced they are a pain in the neck to jig up and weld just for
a car set.
This topic has been covered many many times if you do a search you will find the threads.
Essentially points for the lower wishbone
(1) DON'T use the book lower wishbone design -- it is seriously flawed.
(2) Use a design more like the GTS or MAC or latter MK pattern, which avoid the stress raisers and high local bending stresses inherent in the book
design. Make sure the damper mounting point plate is in line with tube centre lines.
(3) Go up in tube wall thickness and diameter --- in addition to adding bending strengt and stiffness this makes using seamless no problem. But with
seamless align the seam so is is in horizontal plane.
Upper wishbone design is much less critical as the stress levels are much lower.
|
|
|
leto
|
| posted on 29/8/06 at 06:53 AM |
|
|
quote:
Originally posted by welshboy
hi could any one tell me if the steel used to make the wish bones has to be seamless thanks
No, it don't.
Seamless is better only as long as you don't weld it. The moment you put the torch to it most of the advantages go up in smoke. So DOM is good
for pub talk, but really a waste of money.
Steel grade and design are the important parts, get them right and you will have no trouble.
Cheers!
“I'm gonna ride around in style
I'm gonna drive everybody wild
'Cause I'll have the only one there is a round”. (J. Cash)
|
|
|
JB
|
| posted on 29/8/06 at 03:04 PM |
|
|
Tubing
Dom is actually seamed tube. It is welded then formed in the way CDS is. Dom has a more consistent wall thickness so is preferential to CDS for
applications such as propshafts. Look carefully and you will see the seam.
I tried DOM on my wishbones but due to having to flatten the ends slightly to get more surface area to weld in the spherical joint housing, it
split.
I would always use CDS for my wishbones. The quality is consistent, it welds very nicely, it will bend rarther than snap.
Anything "better" such as 4130 or T45 needs a stress relieve.
There are certain parts of a car that you never want to fail, suspension, steering and brakes are those. Design and build these parts the best you
can.
John
|
|
|
britishtrident
|
| posted on 30/8/06 at 06:45 AM |
|
|
This the way it should be done (a GTS bone frome an earlier post by FlakMonkey)
Important points to note
(1) Uses Maxi ball joint
(2) Plate is in line with neutral axis of tubes not just welded on the top surface as it is in the book design.
(3) Ends of plate are nicely radiused
(2) & (3) are vital as they removed a really nasty stress concentration that occurs in the book design that has caused more than a few builders to
encounter bent or broken wishbones.
 
Rescued attachment lowerwishbone.jpg
|
|
|
britishtrident
|
| posted on 30/8/06 at 06:58 AM |
|
|
---
 
Rescued attachment lower.jpeg
|
|
|
britishtrident
|
| posted on 30/8/06 at 07:04 AM |
|
|
Picture from NickGs original post that started the long running thread on wishbone failure.
Probably not the world best made whishbone to start with but it illustrates the point of failure of book design very well.
 
Rescued attachment Nicks.jpeg
|
|
|
britishtrident
|
| posted on 30/8/06 at 07:10 AM |
|
|
one of 907 bones - as always you can tel by the nice welds ---we are not worthy
Note the plate is in line with neutral axis and very nicely radiused to reduce stress concentrations.
 
Rescued attachment w-bones.jpeg
|
|
|
JB
|
| posted on 30/8/06 at 06:47 PM |
|
|
Stress Raisers, nuetral axis etx
Good illustrations and a good point about the gusset on the neutral axis, something I had not considered.
John
Ps Now checking my wishbones!
|
|
|
welshboy
|
| posted on 30/8/06 at 08:01 PM |
|
|
thanks very much everyone for your help maybe i will just buy them thanks again
|
|
|
