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Alu Tube Job advise please.

Limy Sami

Diamond
Joined
Jan 7, 2007
Location
Norfolk, UK
2" dia 16ga, 6"L alu tube, either 6082 or 6063.

1 end m/c'd to a plain spigot OD, the other OD threaded, No problems there.

The bore of this tube is an unmachined housing for a part with .005 - .008 clearance but I'm concerned should the tube may be of shape due to mis handling etc,
This is a free issue material, supplied cut and know the customer will want every inch out of a length

I'll make up a go/no go guage, but what to do with those that ''won't quite'' take the guage?

I thought along the lines of a barrel shaped sizing tool pushed through with lubricant,......... on the arbour press ?? ........... or is the tube likely to spring back?

So any thoughts or suggestions on that aspect please.

Thank you for your time, take care.
 
you can reform the ID with a ball bearing of the right size and some lubricant, force it through for short lengths, pull it for long ones.
[thats what we used at the extruders i used to work at [[alusuisse]]
aquadag was the lube i beleive
NB Barlow/lamson were useing what you suggest by way of a baby beer barrel on a wire rope with a 10 ton Turfor on the end, they were useing oil but we thought the water sol graphite worked better
regards
mark
 
If it's just oval a bit, take a 4"x4" x however deep you have block of UHMW. Bore a 2.1 hole in it, cut ledges on the ends so it'll sit on vice jaws. Saw it in two, mill the ends flat, put in 2x 3/8" dowels in one half, holes for them in the other, and put a coil spring on each.
Put it in a vice, put the tube in tall part to the jaws, squeeze round with the vice.
 
...I thought along the lines of a barrel shaped sizing tool pushed through with lubricant,......... on the arbour press ?? ........... or is the tube likely to spring back?....

What is the temper of the material?


I am not familiar with 6082 or 6063 but I do know that with 6061 - T655 it would just spring back; I have tried similar things.
 
What is the temper of the material?


I am not familiar with 6082 or 6063 but I do know that with 6061 - T655 it would just spring back; I have tried similar things.


Not sure about 6082 but we form 6063 often enough and it doesn't have half the spring that 6061t6 has.
 
or is the tube likely to spring back?

If the sizing tool it large enough to give plastic deformation (stretch the tube slightly) then the tube should stay round. With no mention of the temper I cannot give a size that the tube needs to be stretched before plastic deformation takes place.
 
Go ahead and try then let us know what happens.

I expect you will find you have to go way oversize in order to spring back to the size you want and it will not be constant so many pieces will come out too large.
 
You say that the bore is "an unmachined housing" but do not say whether it is round or not.

If it is round, why not just run a boring pass on it to take it to size?

Why is it your job to make them "to size" anyway, shouldn't it be the correct size when you receive it?

If you didn't quote sizing them, you're not getting paid to do it.

Either send the material back as unsuitable or tag the under-size parts and send them to the customer as they are.

... Unless he's willing to pay you to fix them.
 
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You say that the bore is "an unmachined housing" but do not say whether it is round or not.

If it is round, why not just run a boring pass on it to take it to size?

Why is it your job to make them "to size" anyway, shouldn't it be the correct size when you receive it?

If you didn't quote sizing them, you're not getting paid to do it.

Either send the material back as unsuitable or tag the under-size parts and send them to the customer as they are.

... Unless he's willing to pay you to fix them.

Agreed, in an ideal world I would send the material back, BOTOH things are tight over here in the UK and it's a good customer etc etc,.................. however, don't worry I won't be doing it for nothing. ;)

A boring pass had been my first thought, just wondered if there was another way out.
 
I'm not a machinist but I would like to know HOW you are going to thread one end of 16ga tube? Even if it was very fine thread it will distort!
 
I'm not a machinist but I would like to know HOW you are going to thread one end of 16ga tube? Even if it was very fine thread it will distort!

It's a 1mm pitch thread = 0.65mm or 0.0255'' deep.

With a SHARP HSS tool, I've not experienced problems in the past.
 
Plastic deformation with 6063 T6, roughly 30 Ksi yeild Elastic modulus approx 10 Mpsi.

To get plastic deformation more than 0.3% expansion is needed, expand 0.4% or 8 thou on a 2" part, the part will spring back 0.3% so it will grow by 2 thou after the sizing tool has gone though.


6082 T6 is stronger with 38 ksi yeild, elastic modulus is unchanged so 0.38% is needed before yielding will begin, so 0.5% or 10 thou expansion will be a good start, the part will spring back almost 8 thou.

Even though the part will spring back it will spring back round not deformed (at least that is the theory), you could probably go a few thou more if the tolerances allow it just to be sure, the only thing, the 6061 parts will be approx 2 thou larger if the same expansion tool is used.
 
My thanks to all who've contributed, especially Helical Cut for putting numbers to the process.
However, this morning brought the news that the job's been ''shelved for now'' -and we all know what that means ;-)

Thanks again, take care. Sami
 








 
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