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ERW or seamless for wishbone tubes
Slimy38 - 12/8/13 at 11:04 AM

Just a quick question, do you need seamless tubes for the wishbones, or will ERW be fine? The '...on a budget' car quotes seamless, but the Tiger book says ERW. I can't seem to find any reference to one being stronger than the other.

This is for the 19mm and 25mm tube.

ste - 12/8/13 at 11:08 AM

I used 2mm wall ERW.

Plenty strong enough. Your welds holding it together will be weaker than the seam.

Carbonman - 12/8/13 at 12:37 PM

If your planning on using ERW (which I wouldn't recommend) for the bush tubes as well, make sure that the seam is inline with the centre line of the wishbone tube so that it will be enclosed by the weld. I have seen a few split open when its not.

[Edited on 12/8/13 by Carbonman]

Slimy38 - 12/8/13 at 05:24 PM

quote:
Originally posted by Carbonman
If your planning on using ERW (which I wouldn't recommend) for the bush tubes as well, make sure that the seam is inline with the centre line of the wishbone tube so that it will be enclosed by the weld. I have seen a few split open when its not.

[Edited on 12/8/13 by Carbonman]


Worryingly, the bush tubes were definitely going to be ERW as all the books say it's ok!! It was the longer lengths that I was unsure about. I was aware of the seam orientation though, it just seemed like a sensible thing to do anyway.

ste, looks like you and Gilham both use 2mm ERW, so I think I'm going to do the same.

ste - 12/8/13 at 05:30 PM

The rest of the car is made from ERW and I've not seen one split open yet. I got a 6m length of 25mm and a 6m length of 19mm delivered for £47. That was from the metal store online shop

iank - 12/8/13 at 06:02 PM

They generally only split if the bush seizes - which if you're using stainless crush tubes of the correct length is very unlikely.
When they do they split along one side of the HAZ - it's not clear from most of the pictures posted if this is where the seam is, but the advice in the haynes roadster book is to have the seam directly under the wishbone tube.

Pictures of a split one and discussion in this thread
http://www.locostbuilders.co.uk/viewthread.php?tid=120025

Slimy38 - 12/8/13 at 06:53 PM

quote:
Originally posted by iank
They generally only split if the bush seizes - which if you're using stainless crush tubes of the correct length is very unlikely.
When they do they split along one side of the HAZ - it's not clear from most of the pictures posted if this is where the seam is, but the advice in the haynes roadster book is to have the seam directly under the wishbone tube.

Pictures of a split one and discussion in this thread
http://www.locostbuilders.co.uk/viewthread.php?tid=120025


Very useful, thanks. I'm definitely going to make sure there's no bush binding!! And yes, the picture in the book is very clear on where the seam needs to be.