# Copper flathead screws and nuts



## JPT (Aug 8, 2020)

I need a small batch of copper 145 phillips flat head machine screws with nuts.


Material:
copper 145

Phillips flat head machine screw sizes:
4-40 x 1/2"
6-32 x 1/2" 

Hex nut sizes: 
4-40
6-32

Quantity: 
This is a test, so I am flexible on the quantity. 

I need a minimum of 10 each. 

I have CAD files and PDF drawings available. 

Thanks


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## extropic (Aug 8, 2020)

Rather than Phillips recess, could you go with either slotted (easier = cheaper) or hex socket (easier than Phillips)?

Sanity check: What do you think is a reasonable price for your minimum lot?


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## JPT (Aug 8, 2020)

If possible, I would prefer hex socket.

I can use slotted if absolutely required.


RE: reasonable price

This is for a test of conductive fasteners.

McMaster Carr charges $0.97 each for the 6-32 screws in aluminum, so that is a decent reference point for a conductive fastener.

$0.94 each 4-40 x 1/2" aluminum: mcmaster 97124A139

$0.97 each 6-32 x 1/2" aluminum: mcmaster 97124A239


The aluminum nuts are about $0.05 each.


They sell copper 145 rod:

1/4" 3' $15.32 mcmaster 9100K29

5/8" 1' $33.47 mcmaster 9100K15


So, ~$50 for materials, plus material shipping plus some reasonable amount for the time, labor, machine/shop overhead, etc., plus shipping the finished parts.


But, to be honest, I'm no expert at what to charge, as I am not in the job shop business.


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## extropic (Aug 8, 2020)

Thanks for the reply.

"If possible, I would prefer hex socket." Make your options clear on your drawing to get your best price.


Material costs and shipping are inconsequential compared to the shop time.
Maybe somebody here has an NC lathe and a rotary broach and wants the work.
I only have manual machines so, IMHO, my price would be very unattractive to you.

Have you talked to any professional machine shops? My advice is to do so and get a real $$$$ number. Google "swiss screw machine" and find some people who will talk to you. If they don't want the work, ask for recommendations. Google "specialty fasteners in Texas". Fastener distributors deal with specials for a living.

It should become clear to you that the McMaster piece part prices are for commodity items competitively manufactured in HIGH quantities and not applicable to your 10 pieces each. Sanity check: Fail

A miracle could occur. Maybe somebody has some on the shelf. 

Welcome to The Hobby-Machinist and good luck, really.


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## JPT (Aug 8, 2020)

RE: specialty fasteners

I've been on this for a couple of months and have talked with all that I could find via Google, up to and including the mills in India that specialize in copper. 

So, no known or reachable domestic or overseas suppliers are interested, willing, or able to take this on. 

They deal in multiple metric ton quantities at the top end of the food chain and nobody further down the food chain produces this particular set of sizes and needs. 

For all of them, this material and quantity doesn't make sense in their business model. 


RE: manual machines

Agreed that this job is probably not a good fit. 


RE: material costs are inconsequential compared to the shop time

Very much agreed


RE: on the shelf

That would indeed be a miracle.


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## cbellanca (Aug 8, 2020)

Have you considered brass?


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## benmychree (Aug 8, 2020)

Perhaps a redesign to fit available components.


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## JPT (Aug 8, 2020)

RE: Brass

Thanks for the suggestion.

Brass is actually not very conductive. 

Aluminum is pretty good. 

Copper is best. 

This is a test related to conductive fasteners.


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## JPT (Aug 8, 2020)

benmychree said:


> Perhaps a redesign to fit available components.



Thanks for the suggestion. 

The best available components that I've been able to find are aluminum for a machine screw and a copper rivet. 

I'd like to test a copper 145 machine screw and nut, and thought that this would be a good place to find the available skills, equipment, and availability.


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## JimDawson (Aug 9, 2020)

JPT said:


> I'd like to test a copper 145 machine screw and nut, and thought that this would be a good place to find the available skills, equipment, and availability.



It is a good place, but it's going to cost a lot for some very small screws and nuts.  They don't seem to exist.....Yet.  For instance, my shop rate is $80 - $150/hr depending on what I am doing.  And in this case I don't have the tooling to make exactly what you want.  The real problem is the Philips or hex socket head.  The threads are doable with standard tooling, but the head style you want requires some special tooling.  A slotted head screw can be made with common tooling that many of us have.


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## JPT (Aug 9, 2020)

JimDawson said:


> A slotted head screw can be made with common tooling that many of us have.



If required,  slotted is OK.


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## whitmore (Aug 9, 2020)

JPT said:


> I need a small batch of copper 145 phillips flat head machine screws with nuts.
> 
> Material:
> copper 145
> ...


If push comes to shove, you can get copper rivets in approximately the right size 
<https://www.mcmaster.com/rivets/material~copper/> (note, alloy 110, not 145)
and cold-work the Philips indentation  then maybe with a little bit of honing, a
die can cut the threads (copper is kinda... grabby, you'd want to have a zero rake
edge, like for brass).


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## JPT (Aug 9, 2020)

whitmore said:


> If push comes to shove, you can get copper rivets in approximately the right size
> <https://www.mcmaster.com/rivets/material~copper/> (note, alloy 110, not 145)
> and cold-work the Philips indentation  then maybe with a little bit of honing, a
> die can cut the threads (copper is kinda... grabby, you'd want to have a zero rake
> edge, like for brass).



Thanks for the suggestion.

I have been down this path...






The mechanical connection I need to match for the head is a countersunk, flat head machine screw, so the rivet, while viable for demonstrating some aspects of the goal, remains problematic on the head end.


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## brino (Aug 9, 2020)

One more idea.......

Could you use copper plated "off the shelf" hardware?

But I don't know if it could be done directly or if it would require nickel then copper plate.....

-brino


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## JPT (Aug 9, 2020)

brino said:


> One more idea.......
> 
> Could you use copper plated "off the shelf" hardware?
> 
> ...



Thanks for the suggestion. 

Unfortunately, no. 

This is a test of conductive fasteners and the plating would be inadequate for the required amperage.


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## matthewsx (Aug 9, 2020)

Okay, we have some pictures now  

Can we see the rest of the "test" or is it secret?

If conductivity is the key what about some kind of conductive coating?

John


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## JPT (Aug 9, 2020)

matthewsx said:


> Okay, we have some pictures now



If there's one thing I've got a lot of, it's photos...

These days, I often use them as memory aids.
 



matthewsx said:


> is it secret?



No, not at all.

I'm planning to post the entire test over on Endless Sphere when complete.



matthewsx said:


> If conductivity is the key what about some kind of conductive coating?



Thanks for the suggestion. 

A conductive plating or coating will be inadequate to carry the amperage in this application. 

I need a sizable conductive fastener that won't create high electrical resistance under heavy amperage load - thereby creating a lot of waste heat and voltage drop.


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## JPT (Aug 9, 2020)

For those who are curious about the conductivity of various metals, here's a list sorted by IACS, which is 100% for copper.










source: http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/


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## JimDawson (Aug 9, 2020)

Just to put what you are requesting into perspective, I was looking for something else, and I ran across this screw in my sample drawer.

The picture below is a metric equivalent of roughly a 6-32 x 1/4'' special screw that I made 20 pieces of for a customer.  Material is aluminum, 6061-T6.  A bit easier to machine than copper, but C145 is pretty free machining. 

These were $45.00 each.  These were done on a manual lathe for the turning and threading, and a CNC mill for the head.  But in this case a rather odd shaped head (that I am purposely not showing), thus the required use of the CNC mill.  A screwdriver slot would not require a CNC mill, but the setup time would be about the same, minus the CAM work required for the CNC.

A screwdriver slot would only take about a minute in either a CNC or manual machine.  A hex socket could be milled into the head with a tiny endmill in a CNC machine, but most likely would take about 15 - 20 minutes for that operation, tiny end mills don't like to be fed fast, they tend to break.  A Philips slot could be done the same way on a CNC mill, and would take about the same amount of time.

Your copper screws with a slot head would be about the same amount of work/time as required by the aluminum screw in the picture.

A hex nut could be done in a manual mill with a rotary table or a hex collet block.  Or could be done on a CNC mill.  The setup time for either is about the same.  The actual machining time is a few minutes, it would require 3 or 4 manual tool changes.  Then some lathe work.

Sorry for the out of focus.


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## JPT (Aug 9, 2020)

Jim, 

Thanks for the example. 

Greatly appreciated.

Agreed on all counts for the similarities of the jobs.


I don't currently have a lathe or mill, so can't take on the turning aspects of this myself. 

I can cobble together the nut out of c145 bar stock with a hacksaw, drill press, file, and a tap. 

Yes, cringe worthy and definitely crude but will be effective enough for the test.


If I can find somebody here to turn a sample #4 and #6, that would be great. 

A slot head is fine for the test but it needs to be a countersunk flat head.


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## Flyinfool (Aug 10, 2020)

How critical is the head size. You could start with these copper screws to get a Phillips head and then turn off the wood threads and run a die for the new threads it is just that the head will be a bit bigger than standard.








						CRL P102BC0 Brushed Copper 10 x 2" Wall Mounting Flat Head Phillips Sheet Metal Screws
					

Buy CRL P102BC0 Brushed Copper 10 x 2" Wall Mounting Flat Head Phillips Sheet Metal Screws online at DKHardware.com. Our Bathroom Hardware category offers a great selection of Hinge Replacement Parts and Special Hardware products at the best price!




					www.dkhardware.com
				




The nuts would be easy, hex stock, drill, cut to length and then tap. maybe touch both sides with a C'sink before tapping.

A few other tidbits I found in a quick google








						Custom Slotted Flat Copper Machine Screws - 4/40 x 5/16 in 110 Copper Material | Custom Fastener And Hardware Supplier - Domestic & Import
					

ISO 9001:2008 certified distributor & supplier of custom hardware and fasteners like these custom slotted flat copper machine screws since 1990




					specialfastenersource.com
				







__





						Machine Screws, Copper
					

FastenersClearingHouse.com, The FCH Network, your source for Machine Screws, Copper




					www.fastenersclearinghouse.com


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## JPT (Aug 11, 2020)

Thanks for your research and these suggestions.

Greatly appreciated!



Flyinfool said:


> How critical is the head size.



The head size is the critical dimension. They must match #4 and #6.



Flyinfool said:


> You could start with these copper screws to get a Phillips head and then turn off the wood threads



Unfortunately, I can't use anything that is just a copper coating or plating. I need the entire fastener to be copper.



Flyinfool said:


> The nuts would be easy,



Agreed that I can cobble something together for these myself. The dimension and shape of the nut is not critical for this test, it just needs to match the thickness of #4 and #6.



Flyinfool said:


> hex stock


I could not find anybody who had hex stock in these sizes (1/4" and 5/16").

I found a U.S. mill that had a 5/16" die to extrude the hex bar but would need to fab the 1/4" die for the run, which they were willing to do. 

Their minimum run was $5,000 USD for each die, so $10,000 USD total.

That's a lot more than I am willing to spend on this test.

The industrial minimums are completely understandable given their business model. This is true for all of the mills and fastener suppliers in general. 

That's the reason I am posting here, in the hopes that somebody with the proper machines and available time could turn the #4 and #6 screws from some c145 bar stock. 




Flyinfool said:


> A few other tidbits I found in a quick google
> 
> 
> 
> ...



Thank you very much for the search and this link.

This web site looks familiar, but I am not 100% certain that I have seen them before. They all tend to blur together after a while... 

I'll dig through my kazillions of "no quote / no bid" rejections and see if I can find them.




Flyinfool said:


> __
> 
> 
> 
> ...



I contacted every single supplier for lots of "copper fastener" searches on FCH and they all either never responded or came back "no quote." 


Thanks again for the suggestions, links, and the search.


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## Brento (Jan 24, 2021)

Did you ever find what you were looking for?


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## JPT (Jan 24, 2021)

Thanks for asking. 

No, I was unwilling to pay for a die for a supplier to produce the minimum quantity of the hex rod. 

That project is currently on hold. 

At this point, it will probably wait until I get a mill and a lathe up and running and I'll just use it as a project to learn on. 

You'll probably see me back on the forum plenty then, looking for beginner advice...


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## Brento (Jan 24, 2021)

You couldnt find the size rod for the nuts?


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## Brento (Jan 24, 2021)

I only ask bc i am getting a little lathe running and would not mind giving it a go. I would try it on aluminum first to see if i can do it first. I unfortunately do not have my mill going yet so i could not help you with the hex nuts.


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## JPT (Jan 25, 2021)

Brento said:


> You couldnt find the size rod for the nuts?



Correct. 

The offshore manufacturers, mostly in India, wanted very large minimums, which makes perfect sense given their business models. 

The only U.S. supplier I could find who was willing to manufacture them had a lower minimum, but also needed to create the die to extrude the hex rod.


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## tq60 (Jan 25, 2021)

I have a jar with a few from estate sale find, came from a electrical control person if I recall.

Just used Google and many things came up, copper plated to solid copper.
I would think for electrical work they may be available.

We have a great place in Fresno that sources for home depot and others, mid-valley distributors, if is a fastener try either have it in stock or can get it.

Try them. 559 485 2660

Sent from my SAMSUNG-SM-G930A using Tapatalk


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## Brento (Jan 25, 2021)

I would give them a shot but if not i am open with trying to make the screws for you if you want to chat


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