front lower wishbone (TCA)

[inkitin]

These group buys do get sort of addictive don't they ?

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin

[markv]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin
18. markv

[esp88]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes

[stevieg8571]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)

[bobbrown]

Any views on this being made out of aluminium (7075) anodised.

ally TCA.jpg

It is narrower than the original but the material thickness has been increased to compensate like the center of the "I " section is 16mm and the edges are 10mm which is over double the original.
Also 7075 aluminium is almost the strength of steel at 450Mpa (65250psi) yeild strength or if you prefer a 1" square rod will hold close to 30 tons

Bob

[Specky]

What would be the surface finish, Stove enamel?

TTFN

[bobbrown]

What would be the surface finish, Stove enamel?

TTFN

The finish would be anodised probably black but could be in other colours

SULPHURIC ACID ANODISING
Often known as natural, clear or silver anodising, this is the commonest type of anodising, and the description covers a wide range of processes at different levels. The process differs from hard anodising in that the electrolyte temperature is higher and the current density employed is lower. The types of sulphuric acid are sub-divided into classes mainly determined by the field of application. All anodising processes are sealed unless the film is used as a primer for paint or adhesives.

ANODISING FOR PROTECTION
This is the most common form of anodic coating. Film thickness usually between three and thirty microns. The thinnest films stopping aluminium blackening the hands when handled, the thickest offering substantial corrosion resistance and electrical insulation without the loss of fatigue strength that can accompany hard anodising. The oxide layer is less dense than that of hard anodising and readily accepts a dye. Thicker, high quality films are often referred to as semi-hard anodising .


I have a cost to have the parts made in aluminum and it comes out slighly more than I had hoped but that is in the main to the material selected (7075 aluminium) as it expensive and is around £50.00 /meter
The cost will be £120.00 each

Still awaiting a cost to have them fabricated but I would think it is going to be lower but I will have to wait and see.

Bob

[maz_r]

1. bobbrown
2. Andy_J
3. pinky
4. saska (probably 2 sets - depending on price)
5. paulw
6. Jim B (Muley) possibly 2 sets if the price is right.
7. Kenich
8. MattDon (provisionaly if i can afford them, mine got the thumbs down today)
9.Woody.
10. Dico
11. Specky (possibly 2 sets if the price is right.)
12. Candles. (stainless if at all possible, with poly bushes and ball-joint)
13. John_W (with bushes & ball joint)
14. Denny
15. ashm (£ dep)
16. Richard K
17. inkitin
18. markv
19.Yasuo incl. ball-joint/bushes
20. stevieg8571 (cost dependant)
21. maz_r (also £ dependant)

[ashm]

I'd be ok with strong alloy, so long as someone has done the maths...
Roughly how much weight would this save over the standard item? I suppose probably 1/2 of this arm contributes to unsprung mass?

Also, is suspension geometry likely to be affected much by differing coefficients of thermal expansion if some of the links are alloy and the rest are steel? This can be a real issue with precision mechanisms, I've had problems with it in the past.


Adam

[RichardK]

Hi Bob,

So does that mean we will be looking at +/-£240 each side if you include the bushes and ball joint?

Cheers

R

[theelanman]

are these going to be machined out of 1 peice then......
Id just be chekcin the brittleness before I started......its going to need a good coating of something to stop its oxidisation....it'll react badly with the british salty road otherwise

......

just a couple of thoughts...

[bobbrown]

I'd be ok with strong alloy, so long as someone has done the maths...
Roughly how much weight would this save over the standard item? I suppose probably 1/2 of this arm contributes to unsprung mass?

Also, is suspension geometry likely to be affected much by differing coefficients of thermal expansion if some of the links are alloy and the rest are steel? This can be a real issue with precision mechanisms, I've had problems with it in the past.


Adam

I do not expect this item to be much lighter than the original but also no heavier as aluminium is 1/3 the weight of steel but I have made it thicker than it probably needs to be.

I do not percieve the differing coefficients of expansion to be that much of an issue, as the differance of the two materials over say a 30 degree temperature rise is about .005" if my calculations are correct.

[inkitin]

Bob

Just been doing a bit of google fact finding on 7075 aluminium alloy.

The information I found says that it isn't weldable. Is that true? If so what method is used in place of welding?

Thanks
Roland

[bobbrown]

Bob

Just been doing a bit of google fact finding on 7075 aluminium alloy.

The information I found says that it isn't weldable. Is that true? If so what method is used in place of welding?

Thanks
Roland

No welding as they are machined from a solid billet of aluminium

Bob

[inkitin]

No welding as they are machined from a solid billet of aluminium
Bob

Thanks Bob. I understand now.

[markv]

Any views on this being made out of aluminium (7075) anodised.
It is narrower than the original but the material thickness has been increased to compensate like the center of the "I " section is 16mm and the edges are 10mm which is over double the original.
Also 7075 aluminium is almost the strength of steel at 450Mpa (65250psi) yeild strength or if you prefer a 1" square rod will hold close to 30 tons

- Just a few questions, which might have obvious answers but I'm ignorant in these areas:-

1. Why change the material at all? what are the pros/cons of the original material & design over the aluminium approach?

2. Given that all the material properties are different, how can you be 100% sure that it's going to handle as well as or better than the original under all possible conditions (loading, twist, shock, cracking, corrosion, etc.). I realise that you are thickening parts of the shape but does that necessarily result in all-round improvement?

[MattDon]

i imagine (but could be wrong) but once you get the cad drawings and the mill setup it would be far quicker to make, rather than with welding steel.

i am curious what effect it would have if these were made as lightweight as possible....?

[bobbrown]

Just a few questions, which might have obvious answers but I'm ignorant in these areas:-

1. Why change the material at all? what are the pros/cons of the original material & design over the aluminium approach?

2. Given that all the material properties are different, how can you be 100% sure that it's going to handle as well as or better than the original under all possible conditions (loading, twist, shock, cracking, corrosion, etc.). I realise that you are thickening parts of the shape but does that necessarily result in all-round improvement?

I think the first one is obvious and that is rust but I am still investigating steel and hot dip galvanising or stainless steel, aluminium was an option I wanted to explore as it is resistant to corrosion if anodised.
Stainless steel has some issues that are not unlike the aluminium part but the advantage of the aluminium part is there are no welds and it is one piece of metal so no chance of any of the issues that can creep into welded parts.

When you say the material properties are different then as far as tensile strength they are not that far apart, in some other areas they are but as with all things it is a compromise.
As far as the loading is concerned the main body is more than strong enough due to its profile (shape) to cope with push, pull, bend or twist. This alloy (7075) is aircraft specification aluminium alloy and is about the strongest aluminium alloy available I will be running some calculations to check its strength but it is difficult as I have to make some assumptions on the original as I do not know what material has been used apart from the fact it is steel.
Looking at the weakest areas on the standard unit then the aluminium one is far stronger in these areas and I have where possible used a radius to spread the load.

[Gordon]

Interesting thought, going to Alloy;

The originals had a cross-brace to the triangulation link, obviously making them handed;

During acceleration and braking, I would think the triangulation link plays a big part in keeping the geometry true?

How does the ommision of the cross-brace effect 'things'?

Gordon

[markv]

Thanks Bob