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Old Jun 28, 2006, 05:11 PM
Andrew Mawson
Guest
n/a Posts
Machinable Copper bar

I need to make up four 3/4" BSP copper tails (so 1.041" o/d) for the
ends of the feed pipes for my induction furnace but my recent
experiences machining copper were very mixed, with apparently
identical looking bars varying from horrid sticky stuff to nice crisp
working almost like brass.

What copper specification should I be asking the supplier for to avoid
the sticky stuff bearing in mind that these items carry significant
current so need to be highish conductivity , but also need to be
mechanically able to take a thread being tightened without stripping?
They will be brazed to thick walled copper pipes using Harris Phoson
silver / copper / phosphorous rods.

Alternatively if someone has a bar of suitable material of just over
an inch diameter and about a foot long then don't be shy, get in touch
and I will convert it into pictures of Her Majesty that can
conveniently be further converted into your favourite tipple !!!

AWEM


Old Jun 29, 2006, 03:11 AM
Tim Leech
Guest
n/a Posts
Re: Machinable Copper bar

On Wed, 28 Jun 2006 21:21:43 +0100, "Andrew Mawson"
<andrew@no_spam_please_mawson.org.uk> wrote:

>I need to make up four 3/4" BSP copper tails (so 1.041" o/d) for the
>ends of the feed pipes for my induction furnace but my recent
>experiences machining copper were very mixed, with apparently
>identical looking bars varying from horrid sticky stuff to nice crisp
>working almost like brass.
>
>What copper specification should I be asking the supplier for to avoid
>the sticky stuff bearing in mind that these items carry significant
>current so need to be highish conductivity , but also need to be
>mechanically able to take a thread being tightened without stripping?
>They will be brazed to thick walled copper pipes using Harris Phoson
>silver / copper / phosphorous rods.
>
>Alternatively if someone has a bar of suitable material of just over
>an inch diameter and about a foot long then don't be shy, get in touch
>and I will convert it into pictures of Her Majesty that can
>conveniently be further converted into your favourite tipple !!!
>
>AWEM
>


Andrew

Have you thought of trying this with a coventry die head? The chasers
can be ground to suit copper, & you might have better luck than with
an ordinary die ground for steel. I've got some spare 3/4 BSP chasers
which you or I could regrind.
I've also got some 2" copper bar which I doubt that I'll use the whole
of in my lifetime, but my attempts to machine it have been pretty
awful so it's probably not the stuff you're looking for!

Cheers
Tim

Dutton Dry-Dock
Traditional & Modern canal craft repairs
Vintage diesel engine service
Old Jun 29, 2006, 03:11 AM
Andrew Mawson
Guest
n/a Posts
Re: Machinable Copper bar


"Tim Leech" <duttondock@onetel.no.spam.com> wrote in message
news:bps6a2dmi8bc5ste63h87a8ghf0u13388e@4ax.com...
> On Wed, 28 Jun 2006 21:21:43 +0100, "Andrew Mawson"
> <andrew@no_spam_please_mawson.org.uk> wrote:
>
> >I need to make up four 3/4" BSP copper tails (so 1.041" o/d) for

the
> >ends of the feed pipes for my induction furnace but my recent
> >experiences machining copper were very mixed, with apparently
> >identical looking bars varying from horrid sticky stuff to nice

crisp
> >working almost like brass.
> >
> >What copper specification should I be asking the supplier for to

avoid
> >the sticky stuff bearing in mind that these items carry significant
> >current so need to be highish conductivity , but also need to be
> >mechanically able to take a thread being tightened without

stripping?
> >They will be brazed to thick walled copper pipes using Harris

Phoson
> >silver / copper / phosphorous rods.
> >
> >Alternatively if someone has a bar of suitable material of just

over
> >an inch diameter and about a foot long then don't be shy, get in

touch
> >and I will convert it into pictures of Her Majesty that can
> >conveniently be further converted into your favourite tipple !!!
> >
> >AWEM
> >

>
> Andrew
>
> Have you thought of trying this with a coventry die head? The

chasers
> can be ground to suit copper, & you might have better luck than with
> an ordinary die ground for steel. I've got some spare 3/4 BSP

chasers
> which you or I could regrind.
> I've also got some 2" copper bar which I doubt that I'll use the

whole
> of in my lifetime, but my attempts to machine it have been pretty
> awful so it's probably not the stuff you're looking for!
>
> Cheers
> Tim
>
> Dutton Dry-Dock
> Traditional & Modern canal craft repairs
> Vintage diesel engine service


Tim,

Thanks for that. Yes I will do it with a diehead - far the easiest
option and I have the chasers.

If you have 2" copper bar then at todays prices you can probably
retire <G>

AWEM


Old Jun 29, 2006, 05:11 AM
Peter Neill
Guest
n/a Posts
Re: Machinable Copper bar

On Wed, 28 Jun 2006 21:21:43 +0100, "Andrew Mawson"
<andrew@no_spam_please_mawson.org.uk> wrote:

>I need to make up four 3/4" BSP copper tails (so 1.041" o/d) for the
>ends of the feed pipes for my induction furnace but my recent
>experiences machining copper were very mixed, with apparently
>identical looking bars varying from horrid sticky stuff to nice crisp
>working almost like brass.
>
>What copper specification should I be asking the supplier for to avoid
>the sticky stuff bearing in mind that these items carry significant
>current so need to be highish conductivity , but also need to be
>mechanically able to take a thread being tightened without stripping?
>They will be brazed to thick walled copper pipes using Harris Phoson
>silver / copper / phosphorous rods.
>
>Alternatively if someone has a bar of suitable material of just over
>an inch diameter and about a foot long then don't be shy, get in touch
>and I will convert it into pictures of Her Majesty that can
>conveniently be further converted into your favourite tipple !!!
>
>AWEM
>


The grade of copper used for EDM electrodes has to machine easily to
get a good finish replicated after sparking, so this one would
probably be the one to go for.
Not sure what the grade would be, but I'm sure that Kevin Steele would
know exactly what it is if you paged him.

Peter
Old Jun 29, 2006, 05:11 PM
Kevin Steele
Guest
n/a Posts
Re: Machinable Copper bar


>
>The grade of copper used for EDM electrodes has to machine easily to
>get a good finish replicated after sparking, so this one would
>probably be the one to go for.
>Not sure what the grade would be, but I'm sure that Kevin Steele would
>know exactly what it is if you paged him.
>


Did someone call? Yes, indeed it does machine very nicely, none of
the burrs you usually get with copper and it isn't "sticky" either.
It's refered to by different people as different things, free cutting
copper, telerium copper, "telco", etc.

It's quite expensive, but then so is any copper. the cheapest
supplier we've found is a company called RDK (let me know if google
doesn't reveal anything and I'll look up the number when I'm at work
tomorow).

It is definately worth the extra over normal copper, as it machines
like a dream compared to any other grades -we'd never use anything
else at work.

Regards
Kevin
 


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