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URGENT help needed with crush tubes
robertst - 6/3/07 at 12:20 PM

just bought the stainless tube to make the crush tubes and it was f**ing expensive!

well, what do you know, it's smaller than the other ones i had so these rattle slightly inside the polybush.
to give u an idea, 18mm is not a snug fit and these are 17mm.

does the crush tube need a tight fit in the polybush? would this tube i bought expand in any way when torqued up?

basically.... have i just wasted my money? is this absolutely useless?

thanks!

[Edited on 6/3/07 by robertst]


Howlor - 6/3/07 at 12:38 PM

The tube wont expand but the bush may squeeze onto it when tightened up. You don't want any play though.

Steve


DavidM - 6/3/07 at 12:43 PM

quote:
Originally posted by robertst



does the crush tube need a tight fit in the polybush? would this tube i bought expand in any way when torqued up?

basically.... have i just wasted my money? is this absolutely not useful?

thanks!


It does need to be a tight fit. You'd find that the tube is too thick to expand.

Is there nothing else on the car you can use the material for?

David


robertst - 6/3/07 at 12:50 PM

17mm diameter, 3mm wall stainless steel? i dont think so. its heavy, can't weld it.

bugger! another day lost!

do you by any chance know the interior diameter needed? i mean 18mm goes fine, but it would rather be 18 point something to be a tight fit.



[Edited on 6/3/07 by robertst]


robertst - 6/3/07 at 12:58 PM

Wait a tick... according to the ANSI wotsits, Stainless steel comes in specific sizes, and specifically to pipes, there is 3/8 in. which is 17mm and 1/2 in. which is 21mm so theres NO WAY of getting an 18mm stainless steel pipe!...


[Edited on 6/3/07 by robertst]


Peteff - 6/3/07 at 02:28 PM

Try looking for tube instead. It is measured by OD and wall thickness. Why does it need to be stainless?


robertst - 6/3/07 at 02:36 PM

read here not long ago that normal steel ones rust...

what do you mean by tube? a solid one which i will have to drill?

how have people done theirs is what i am dying to know!


bigandy - 6/3/07 at 02:41 PM

Buy the stuff oversize and turn it down to the correct size needed?

Also ANSI standards are American (American National Standards Institute), which is probably why they specify imperial measurements, instead of the proper metric measurements. You might want to see if the amterial you require is available in metric sizes (i.e. DIN or ISO or BS standards)...

cheers
Andy


Mr Whippy - 6/3/07 at 02:46 PM

quote:
Originally posted by robertst
read here not long ago that normal steel ones rust...

what do you mean by tube? a solid one which i will have to drill?

how have people done theirs is what i am dying to know!



most folk seem to coat them in grease anyway to stop the suspension squeaking, so it won't rust...

mine are all mild steel and I'd bet that most cars are the same.


Bluemoon - 6/3/07 at 02:54 PM

Yep mine are Mild steal coated in grease.. And that's the way all standard MK's are done. I would use mild first then change them if they rust up..

Dan


daviep - 6/3/07 at 02:54 PM

Found this on the aalco website, seems to indicate you can get 18mm stainless tube as a standard size.
Description
Description


Regards Davie


robertst - 6/3/07 at 03:31 PM

oh you're a life saver!!!! now i can go complain to my supplier.

should i get 19mm just in case?

just read the LB archives on the crush tube dilemma (didn't now it was a recurring theme) and the consensus is a tight fit in the polybush.


robertst - 6/3/07 at 07:55 PM

no luck... steel supplier says there's no such thing as 18 or 19mm stainless (at least in Europe) and so, the next size is 21.3mm diameter. He did reccomend me to enlarge the hole in the polybush to 21.3mm. any thoughts?

talked to a guy with a lathe earlier on and says he can do it.

Both men asked me the same question: "why stainless steel?" one of them even reccomended bronze or brass (he said it was stronger than stainless)!!!

also even for this size (21.3mmų 3mm wall) i have to buy all 6 metres of it, so it'll cost me around 100 euros just for the material (of which i will be just using what, 60cm?).

SHOULD I REALLY BOTHER?! should i just stick with regular steel?

cheers!

[Edited on 6/3/07 by robertst]

[Edited on 6/3/07 by robertst]


robertst - 6/3/07 at 08:47 PM

anyone? i really need your help to decide now as i have to call these guys up first thing tomorrow.


MikeRJ - 6/3/07 at 09:29 PM

I would just go for mild steel to be honest, if you stick plenty of grease on it when assembling it won't rust.


robertst - 7/3/07 at 12:02 AM

and it should definitely cost a lot less than stainless.

stainless is more brittle than iron anyways, so its not so good for mechanical purposes (this is the conclusion i didn't understand from the lathe guy)

thank you very much. i really just needed someone to tell me that because i was starting to chew out the walls...


James - 9/3/07 at 02:41 PM

Most people here have used mild steel AFAIK.... and there's a little more rain here than in Spain!