Copper Tellurium , perhaps not the best

[Overspeed]

Hello

I am in process to design an improve SR4 copper post with self levelling , I have checked and

Silver = 105%
Copper = 100%
Tellurium Copper = 93% ( full hard )
Brass = 28%
Bronze = 15%

Tellurium is an alloy element to improve machining not conductivity but increase a bit the hardness

beryllium copper alloys are very strong and hard but IACS is the brass range or a bit over but not at the copper level

I try something and post details

Regards
OS
 

[jpanhalt]

I have used tellurium copper many times.  Reasonably hard and easy to machine compared to pure; however, seeing your location, is its very weak radioactivity an issue?

[TimFox]

The geometry of binding posts and similar connectors does not require extremely high conductivity.
Pure copper or pure silver are both too soft for the application.
For that reason, pure metals are rarely used for connectors, although common for wires.
An important parameter when choosing alloys for this purpose is the thermal emf against copper, where the flexible wires are normally reasonably-pure copper.

[Overspeed]

The geometry of binding posts and similar connectors does not require extremely high conductivity.
Pure copper or pure silver are both too soft for the application.
For that reason, pure metals are rarely used for connectors, although common for wires.
An important parameter when choosing alloys for this purpose is the thermal emf against copper, where the flexible wires are normally reasonably-pure copper.

Hello
I agree I prepare some test regarding copper / tellurium versus pure copper ( spade) versus copper / beryllium as some beryllium alloy reach 60 IACS .

Pomona banana plug ( male ) have spring contact in copper beryllium , I have read some where than Fluke multimeter use copper beryllium post but I have no confirmation.

I agree than conductivity and Thermal electrical force are not the same concern.

Regards
OS

Regards
OS

[Overspeed]

I have used tellurium copper many times.  Reasonably hard and easy to machine compared to pure; however, seeing your location, is its very weak radioactivity an issue?

Hello
thanks I will check as some TIG electrodes are now banned or the same stupid reason , I have a quite big radium alarm clock ...

Regards
OS

[Overspeed]

Hello

An interesting data able or contact value between metal and alloys

I link also the complete article

Regards
OS

[TimFox]

It is very important to note the last line in the table:  copper vs. copper oxide, which is a huge thermal emf.
Gold plating introduces a very small thermal error, but will not oxidize under normal operation.

[Overspeed]

It is very important to note the last line in the table:  copper vs. copper oxide, which is a huge thermal emf.
Gold plating introduces a very small thermal error, but will not oxidize under normal operation.

Hello
I agree copper oxide is worth , light electropolishing allow to keep surfaces clean

Be aware of gold plating as that generally not homogeneous (at microscopic level ) up too poor when done on cheap parts / components and with time copper oxide start to appear , best is to use PVD  coating and not electrolyse process.

To test the quality regarding Gold coating is to let the part on a water salted dripped paper towel , 24 h later that shall show any green traces

Regards
OS

[Conrad Hoffman]

Pure copper is miserable to machine and tends to gall against other materials. It bends easily. Bad choice for connector parts. Tellurium copper is no problem to machine, doesn't bend so easily and has plenty of conductivity. IMHO, the best choice.

[Overspeed]

Pure copper is miserable to machine and tends to gall against other materials. It bends easily. Bad choice for connector parts. Tellurium copper is no problem to machine, doesn't bend so easily and has plenty of conductivity. IMHO, the best choice.

Hello
I agree regarding copper machining but copper tellurium is still not amazing regarding hardness , copper beryllium alloy ( some of them ) have several interesting specs.

I prepare a setup to test copper beryllium / copper .

Gold coating is another concern regarding wear , homogeneity ....

But take in consideration than a lot of standard resistor don't seems to have gold plated post or pure ''copper'' surfaces see pics so ?

Regards
OS

[jpanhalt]

Beryllium copper is hard and beryllium is considered a critical metal.  Considering its potential toxicity, it is not highly regulated in the EU because of that.  Here's a quote from beryllium.eu :

Beryllium is not restricted under REACH for professional uses. Beryllium is only restricted for general public uses (REACH Annex XVII - Entry 28). The uses of beryllium-containing casting alloys outside industrial installations (dental or jewellry for example) is advised against.

Presumably, your application is commercial.  Just be aware of iits toxicity.

[Overspeed]

Beryllium copper is hard and beryllium is considered a critical metal.  Considering its potential toxicity, it is not highly regulated in the EU because of that.  Here's a quote from beryllium.eu :

Beryllium is not restricted under REACH for professional uses. Beryllium is only restricted for general public uses (REACH Annex XVII - Entry 28). The uses of beryllium-containing casting alloys outside industrial installations (dental or jewellry for example) is advised against.

Presumably, your application is commercial.  Just be aware of its toxicity.

Hello


Thanks

CuBe cable and connectors are used or high range hi-fi and available in EC without limitation to sale .

CuBe is safe or all alloy and use in a lot of special purpose alloy including springs  , Be is toxic only when that a pure metal and when you breath dust of Beryllium as that destroy lugs.

Be metal is very difficult to purchase as that '' nuclear weapon metal '' so that controlled ( import / export and other delirium ) not included it is a high cost metal , only easy source was Russia but now ....

REACH is the Everest of stupidity as a lot of EC specs are ridiculous too.

Regards
OS

[jpanhalt]

I am not saying you shouldn't use Cu-Be alloy.  From my understanding, there are two types of beryllium toxicity. One is from soluble compounds (salts) of beryllium.  They can form regardless of whether it is in an alloy or not. For what you are doing, that is a very low risk.  The same applies to lead.  Its soluble compounds are toxic.

The second type is berylliosis from inhalation of its dust.  That's an immune response to beryllium and can occur with dust from beryllium alloys too.  Metallic lead, in contrast, is relatively non-toxic.  Gunshot victims who have metallic lead pieces in their soft tissues do not show significant increases in blood lead levels.  The exception to that is when the lead is very near to a bone.  The mechanism for that is explained elsewhere.  Just be cautious of the dust regardless of whether it is pure or an alloy.

[TimFox]

Berylliosis (from inhalation of Be dust) is very serious.
One of my professors, a junior member of the Manhattan project, lost a lung from it, although he died many years later from the disease.
Apparently, he had polished beryllium windows used for radiation detectors during the project, and inhaled the dust.
However, normal use of BeCu alloy, where the Be "precipitation hardens" the copper in a similar manner to carbon in steel, should not create that problem, which requires inhalable dust.

[Conrad Hoffman]

I've got a Guildline standard resistor with, I think, pure copper screw terminals. So, it's been done without too much trouble. With threads, I'd be using form taps and rolling threads if possible. I don't think beryllium copper is a problem, though I'd avoid sanding or grinding it.

[TimFox]

I've got a Guildline standard resistor with, I think, pure copper screw terminals. So, it's been done without too much trouble. With threads, I'd be using form taps and rolling threads if possible. I don't think beryllium copper is a problem, though I'd avoid sanding or grinding it.

One could make a screw-terminal binding post where the male and female threads are inserts, and the electrical mating surfaces are pure (or plated) copper.  Could those Guildline terminals use that scheme?
My tries to tap holes in pure copper were all failures.

[Conrad Hoffman]

I think the Guildline is just plain old copper. If you've never used form taps, you should give them a try. They require a non-standard tap drill size but leave no chips and thread close to the bottom of blind holes. There are small external threading tools with rolls, but it costs a bit to get into that system.
https://www.mscdirect.com/browse/tn/Threading/Taps/Thread-Forming-Taps?navid=2106038&refinements=Brand%3ABalax
https://www.alouettetool.com/thread-rolling/   (just so you can see the external ones)

[Kean]

If you've never used form taps, you should give them a try. They require a non-standard tap drill size but leave no chips and thread close to the bottom of blind holes.

Very interesting.  I have heard of them, but never researched further.
There is a good video from Balax I found.

[Overspeed]

I think the Guildline is just plain old copper. If you've never used form taps, you should give them a try. They require a non-standard tap drill size but leave no chips and thread close to the bottom of blind holes. There are small external threading tools with rolls, but it costs a bit to get into that system.
https://www.mscdirect.com/browse/tn/Threading/Taps/Thread-Forming-Taps?navid=2106038&refinements=Brand%3ABalax
https://www.alouettetool.com/thread-rolling/   (just so you can see the external ones)

Hello
Thanks
I have a cold rolling head or lathe but not die or small thread , and some ''no chips tap'' I use them to tap 17-4PH steel rods or race car .

Main concern / problem with copper is the cutting lubricant  as most o then stain copper other are not really dedicated or copper as galling is worth .

Regards
OS