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new wishbones to avoid rod-end in bending- this is getting expensive

FuryRebuild - 14/8/12 at 02:27 PM

Wow - in order to do this right and have the spherical bearings captured and avoid rod-end-in-bending, it's starting to get a little expensive. However, I'm going to motor on.

I've got my 5/8 spherical bearings, bearing cups and cir-clips from McGill motorsport - great service. Ł40, give or take.

reamer to take my upright out to 5/8 from the tapered hole to an accurate 5/8" hole: Ł40

5/8" socket headed cap screws, 4" length: Ł28 for two. I could have got bolts at the same length, but they were Ł24 (both prices included postage and vat).

Various others, about Ł30 to complete the manufacture.

However, I'll have a pair of wishbones, done properly, engineered well for Ł75 each, and yes, I'd stake my life on them.

The bolts were the proper expensive part, and I've ended up having to go stainless from westfield fasteners to get the sizes I want (3" length isn't enough to go through the misalignment spacers, bearing and upright whist giving 2 turns of the thread for safety.

[Edited on 14/8/12 by FuryRebuild]

SausageArm - 14/8/12 at 02:36 PM

It's urprising how costs add up when doing anything to your car.

Do you have any photos of the wishbones, before/duting/after?

MikeRJ - 14/8/12 at 02:38 PM

5/8" sounds huge, does it really need to be that large?

Mr Whippy - 14/8/12 at 02:38 PM

I don't like the idea of stainless bolts used for suspension, they should normally be 8.8 grade steel ones

FuryRebuild - 14/8/12 at 02:38 PM

Hi SausageArm

Firstly, I must complement you on such a great name.

I have learned that everyone here is picture-hungry, so I will provide. I'm waiting until I get the bolts in before I start putting pictures up, and I have some new stepped-hole brackets I need back from the laser-cutters first to allow me to make the suspension height adjustable.

Cheers
Mark

FuryRebuild - 14/8/12 at 02:51 PM

My Whippy

You raise an interesting point. I've ordered a2-70 bolts, with a tensile strength of 700N/mm2 and yield strength of 450N/mm2.

This compares with 828 and 635 respectively for 8.8.

I'm going to need to go away and see if I'm comfortable with the numbers. I can't get what I need in either steel or A4-80. If you know someone who's got a supply, I'd love to know.

Thanks
Mark

40inches - 14/8/12 at 03:07 PM

quote:
Originally posted by FuryRebuild
My Whippy

You raise an interesting point. I've ordered a2-70 bolts, with a tensile strength of 700N/mm2 and yield strength of 450N/mm2.

This compares with 828 and 635 respectively for 8.8.

I'm going to need to go away and see if I'm comfortable with the numbers. I can't get what I need in either steel or A4-80. If you know someone who's got a supply, I'd love to know.

Thanks
Mark

Couldn't you use 5/8' to 1/2' Rose Joint Reducers,High Misalignment | eBay

and 1/2" bolts?
1/2"x4" S grade Ł12 for 25 here

[Edited on 14-8-12 by 40inches]

phelpsa - 14/8/12 at 03:16 PM

quote:
Originally posted by 40inches

quote:
Originally posted by FuryRebuild
My Whippy

You raise an interesting point. I've ordered a2-70 bolts, with a tensile strength of 700N/mm2 and yield strength of 450N/mm2.

This compares with 828 and 635 respectively for 8.8.

I'm going to need to go away and see if I'm comfortable with the numbers. I can't get what I need in either steel or A4-80. If you know someone who's got a supply, I'd love to know.

Thanks
Mark

Couldn't you use 5/8' to 1/2' Rose Joint Reducers,High Misalignment | eBay and 1/2" bolts?

The holes in the uprights are 5/8 by the sounds of it.

I would (personally, i am not recommending it to you!) be ok using 5/8 stainless bolts as they are so massively over specced. However fatigue of austenitic stainless is a bit of a difficult one IIRC.

FuryRebuild - 14/8/12 at 03:20 PM

The problem is in the upright tapered hole. It starts out at 5/8 and goes down to 1/2, so if I went with 1/2 (my first choice) then it would be rattling around in there.

5/8 was the first size I could come across that would give me clean location and not end up with it rattling around.

Thanks
Mark

40inches - 14/8/12 at 03:35 PM

Seem to be Ł1 each here not tried to buy them though

britishtrident - 14/8/12 at 03:58 PM

Using even high grade stainless bolts in this application would worry me.

FuryRebuild - 14/8/12 at 04:01 PM

Hi BritishTrident

A4-80 are similar to 8.8. I'm stuggling to find them as well at the moment; it's a little tricky at work right now.

meh - saying that, I'm not going to stick with my original wishbones, the force goes around too many corners.

FuryRebuild - 14/8/12 at 05:05 PM

Right then

After all the good advice, I've sent the stainless bolts back. I am assuming that everyone here who has said "don't do that - stainless is wrong in that application" are doing so not because of the strength in the bolt, but because stainless has a different fatigue characteristic to 8.8 alloy. Or are you doing it because you remember the specification?

Either way, having a wheel fall off because one didn't listen isn't a funny thing.

I've found malpas tractor parts, who sell 8.8 rated bolts at the right spec and length for peanuts, and here's the link

Thanks
Mark

[Edited on 14/8/12 by FuryRebuild]

eddie99 - 14/8/12 at 05:08 PM

Don't want to scare you but McGill Motorsport rod ends are not great

FuryRebuild - 14/8/12 at 05:10 PM

Let's see how I do.

I tend to take them off and check them every 6 months anyway - if they're getting too stiff or the surfaces are pitting, I scrap them.

phelpsa - 14/8/12 at 05:26 PM

quote:
Originally posted by eddie99
Don't want to scare you but McGill Motorsport rod ends are not great

That's not the experience I've had. What are you comparing them to and in what application?

Here's the spec sheet for the McGill 'Ultra hight performance' rod ends: http://www.qa1.net/qa1_motorsports/drag-and-street/rod-ends/endura-racing-series/xm-series-chromoly-steel.html

[Edited on 14-8-12 by phelpsa]

eddie99 - 14/8/12 at 05:30 PM

Just I've bought of rally design, auroras from specialist bearing places, then McGill

I bought the high grade from McGill and were already not very loose and quite stiff.

However McGill are cheap, much cheaper than buying the auroras.

+ I have friends in various differnt race cars that have had a fair few McGill rodends break on them

phelpsa - 14/8/12 at 06:23 PM

quote:
Originally posted by eddie99
Just I've bought of rally design, auroras from specialist bearing places, then McGill

I bought the high grade from McGill and were already not very loose and quite stiff.

However McGill are cheap, much cheaper than buying the auroras.

+ I have friends in various differnt race cars that have had a fair few McGill rodends break on them

Eddie,

All spherical bearings should start off with some break out torque, this is what you felt as 'stiffness'. This is quite high in the qa1 bearings due to the liner design. They loosen up in a short period of time.

I suggest that these friends have not specced the bearing properly. If they have replaced a higher spec, more expensive bearing with one of these then more fool them! Have they taken up their issues with qa1, and checked that they were operating within their specified load limits?

owelly - 14/8/12 at 06:25 PM

As is the way of Locostbuilders lately, I'd like to point out something you've done wrong. Something I wouldn't have done. And/or something that is downright dangerous. I can't think of anything just yet but I'll give it some thought....

Mr C - 14/8/12 at 07:01 PM

quote:
Originally posted by owelly
As is the way of Locostbuilders lately, I'd like to point out something you've done wrong. Something I wouldn't have done. And/or something that is downright dangerous. I can't think of anything just yet but I'll give it some thought....

+1 on that, though to be fair to Eddie he is very well intentioned,

perhaps other threads are clouding the issue as you are right about the negative feedback currently evident lately. I'm currently planning a suspension conversion for my next project and am very interested n the Current issues on suspension design and rod ends etc, though it is very difficult to sift out the helpful and less helpful responses, the downright destructive ones are pretty easy. Though entertaining to an extent they are getting boring at best and go against the helpful nature of this forum and its good reputation at worst.

I'm developing some front suspension taken from a well proven sportscar for use in front and back applications in a lmp type design. I was gong to post for advice pointers etc, not sure that I will now, perhaps I'll post up the aftermath of a rod end failure then no doubt I'll have someone posting up "if only he asked us I could have told him it was sh!te and he'd kill himself".

I don't know the answer to the current way of the forum, perhaps in time things'll settle down again, anyhow best of luck to the op and please keep us informed of progress.

FuryRebuild - 14/8/12 at 07:19 PM

Mr C

This is indeed turning into a good thread.

As is often the case, some get it, and some don't when it comes to the mods one makes. There was a really mixed set of comments to the spider I made for my engine bay, but quite a few understood the need to amke it stiff, and the engineering involved to get it there.

In this thread I've had great responses, and they've made me change my approach (i.e. not go for stainless bolts, although I had to work out why myself).

I now know about bolt head markings, steel alloy ratings and other things. I'll worry when everyone tells me i'm brilliant.

I think this has been a lively thread, and I wouldn't even mind a good argument if done politely.

Take a look at my blog (furyrebuild.co.uk) and you can see the mods I've made.

I'm going to continuously publish them here as well even though it can mean filtering a little chaff; I feel I owe it to the community for the help I get, and support when I've designed something correctly.

Cheers
Mark

owelly - 14/8/12 at 08:25 PM

Incidentaly, I wasn't aiming my previous post at anyone in particular.......