Hey all,

I'm in need of an alloy tube of a rather special internal diameter. which I can't find anywhere in retailshops.

it must be closest to 39.6mm I can get but not smaller than that, and not bigger than 39.9mm, the internal diameter needs to be absolute smooth and even.

I was thinking on getting the first step smaller tube with a thick wall, and machine the inner way to spec on a lathe, does anyone knows how to do this, taking in mind that the tube must be 41cm long.
Or would a honing session be a better option?

if there's anyone who can perform this please feel free to share.

there will be intercooler cores inside the tubes that are extruded out of pure alluminium with fins so thin that touchin them would be able to break them, which is why the inner tube must be absolutly smooth, it may not touch the fins

grtz Thomas (holland)

Redesign the intercooler to fit inside a std bore of tube

410mm isnt too bad as its a fairly big bore, you could bore it out on a big lathe. But the tube would have to be supported on a steady. Over that sort of length you can expect to see a bit of taper and size variation though.

Not sure what you mean by absolutely smooth (impossible), you will get a pretty good finish by boring it out on a lathe, probably down to about 2mircrons Ra.

You will need to speak to a local machine shop about what you need, as they will be able to advise. You may be able to get a bit of tube bored out on a mill to the right size as well. Whatever route you choose you will need a very long cutter or boring bar. The easiest solution is to design things to use std parts in the first place...

David

[Edited on 27/2/07 by flak monkey]

Hey Monkey,

That's the problem, you can't design and make these intercooler cores yourself. and these parts are standard.

and I am desing it to fit my needs, just happens to be that the best air-water heat transfer cores in the world are 39.5mm in diameter (lots of thinking behind that) and the fins on the core must not be further from the housings wall than between .1 and .3mm

so I'm left with the problem to solve.

cores are from Laminova, and not the kind of items you can design and make in you're own toolshop...
Laminova doesn't sell the core housings anymore because the custumours they normaly deliver to integrate them into intake manifolds (lotus, Fordusa, bugatti ferarri etc etc)

I'll try and contact a machine shop over here in holland, but there are not many willing to help custumours that are not company's....

in the meantime I'm stil open to suggestions.

grtz Thomas

[Edited on 27/2/07 by thomas4age]

If you search on marktplaats.nl for "draaiwerk" you will find several people who can probably help you.

But I am wondering how you let the air flowing true this tube.

Grtz. Ruud

there will be no airflow through the tube,

air flows through the finns on the heat exchanger, and the tube I need it to trap the air inbetween the finns, so it doesn't escape the intercoolercore giving a less effective coolingdown period.

Air enters though a lengthways slot in the top of the tube (tube lies horizotal), it then gets forced inbetween the finns hopfully stays inbetween the finns and exits through a slot on the bottom of the tube.

the maximum gap inbetween the fins on the core and the core-housing must be .3mm if any bigger air will leave the fins prematurly and not be able to put it's heat into the fins on the core, there's a coolant flow through the core which takes the heat away.

hope this is understandable, I tru and scan a piccie with what I mean.

grtz Thomas

ps Bedankt voor de marktplaats tip!

I might well have missunderstood your description but why no make up your own tube using round formers with an ID equal to your tube ID plus tube material thickness - as long as the material width is the exact circumference of the tube the joint would be minimal and could be glued or flow soldered closed with an overlay - you are putting a slot in the face of the tube anyway.

To make the tube roll the tube marginaly bigger than diameter required and then force into formers.

[Edited on 27/2/07 by Ivan]

Try here,

http://www.aircraftspruce.com/catalog/mepages/alumtube_6061t6.php


1 5/8" and a good quality reamer, plenty of coolant.

hmm, can you not mkae a fomer e.g. wood of the right diameter and then bend a sheet of aluminium around it then weld (not sure how you will be avble to clean up the weld insdie the tube. (maybe joggle one end and have it overlap - is is gricitcal if there is a small gap in the inner tube wall?

I've got a load of tube with a bore of 39.6ish. It's aluminium thick walled scaffold pole.

Ive got some of that also , mine measures 40,2 so didnt suggest it.Maybe there is some manufacturing tolerance so it may be worth checking it out, the bore is quite good and would easily polish a bit if required.
Is this standard scaffold tube ? I am going to use mine for a zetec inlet manifold and would like to get some more if its easily available.
Paul.

quote:

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Originally posted by gazza285
I've got a load of tube with a bore of 39.6ish. It's aluminium thick walled scaffold pole.

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39.8mm is perfect so I have emailed out to the aircraft buisness (thanx heaps for that link!!!)

just hope they're willing to help me out.

39.6 is just to small, the core fins are extruded to 39.5 +/-0.1 so they could touch.

If I can't find something usfull I'll conact you and if you agree buy 4, 41cm pieces of the tube, and polish them out.

thanx for all the help!

grtz Thomas