Where the hell am I going to find...

[corksil]

...Lead washers?

8mm OD, 6mm ID, roughly 1mm thick.

I've tried all the nuclear shielding companies, none can fill an order this small for an acceptable price.

As for the application -- it has something to do with mating two metal alloys with a super malleable intermediary that will deform and fill an un-even gap when crushed. Kind of like a crush washer for a drain plug -- but instead of copper I'd like to try using lead first as it is much softer than copper.

[Flying]

I would try getting lead stock and working from there, but you'll have hard luck finding any shop willing to machine it.

https://rotometals.com/lead-sheet/sh...2-5-lbs-sq-ft/

Honestly, I would just mark a template and cut it by hand.

[SteveL]

Copper work hardens take a copper washer and heat it to dull red.
It will be soft till you start bending it.

Steve

[Triple Jim]

How about using some 0.015" solder and wrapping a few turns? Or using a rubber O-ring? Or a Parker Stat-O-Seal?

One thing you're requiring that makes it difficult is the 1mm cross section, both thickness and section width. If I really had to have this part, I'd probably try buying or making a 6mm punch and an 8mm punch. Hollow punches like this. You might have to re-sharpen the end to more of a knife edge for the 6mm hole.

[Motofool]

Could you melt several balancing weights for car's tires on a flat/horizontal surface?
If you achieve a sheet of around 1 mm of thickness, you could use the tools shown above for the holes.
If you require more precision, you could cast a cylinder instead and produce the washers in a lathe.

[Triple Jim]

McMaster-Carr sells lead sheet. The 3/64" thickness is not far from 1mm thick.

[SLOWn60]

A little drywall mud, a few washers of the size you need, small jar of Vaseline, lead fishing weight(s) or flux free lead solder and a heat source. Coat the washers in a thin layer of Vaseline (mold release) and press the washers into or pour the mud over the washers. When dry; a small pick or screwdriver to scrape off and remove the washers from the hardened mud. Melt the lead into the molds (hold them with pliers!!!) and voila!!!

[corksil]

Dangit you guys a freakin wizards. Each one of these ideas is brilliant. I have no idea why I didn't come up with any of them.

I've ordered a few tools and components, time to do some testing and see how this turns out.

From my research -- lead does not work harden the way copper does. Copper may be a better option.

Thank you all very much.

[corksil]

Following up..

After making a few lead washers and testing things out I've determined lead to be too soft of a material for this project.

I ordered a few more tools and did a little more research and I'm going to try phase two of the project with copper washers. It is impossible to find aluminum or copper washers in the size dimensions needed.

The only thing I've been able to find in the right size for a reasonable price is steel but that will not work for this application.

It seems that the melting point of copper is close to 2k*F. It doesn't look like I'm going to be able to pull that off with a map gas torch.

Time to get creative.

[Mohawk]

Aluminium or copper bar can be drilled to required ID then parted off to the thickness you require on a lathe ! Any local engineering place with a lathe can mak these for you !

[Mechanikrazy]

2mm between OD and ID is not much material to work with...

Mohawk's method would be the most surefire way to get something working.

Alternatively, as a cheap method, could simply punch, bore, or drill/mill an 8mm OD copper washer (easy to find in 2mm or 4mm ID).

[Hellmutt]

Why such a small OD? Is this confined to fit inside of a seal valley or channel? If you're not bound so much by the OD, check your local Freightliner truck dealership....they sell Mercedes/Detroit branded copper sealing washers about the same ID as you're after

Edit - just caught the fact your in Hawaii, so there's likely no class 8 truck dealerships around huh?! LOL!

[corksil]

Nope. No class 8 truck shops. Only one true machine shop and they cannot fulfill my needs.

As of this point in time I have several options.

-scrap the project and dedicate the materials toward a different purpose
-melt down the copper and re-cast it into a shape that I can tool to my needs
-buy washers of proper OD required and figure out how to drill ID to needed size
@Hellmutt -- there isn't really a proper "required" size, this project has been a process of trial and error.
@Mechanikrazy -- widening an existing hole in a copper washer is a bugger to accomplish. The washer has to be held securely which cannot happen horizontally in a bench vise because the washer deforms when squeezed. I suppose I could try to clamp it vertically but even with a brand new sharp drill bit, cutting oil, and very high speed with light pressure -- the washer tries to bend sideways.

If the drill bit "catches" and dives/plunges, all bets are off and the washer is mangled and it has to be removed from the drill bit with pliers.

This stuff is a little more tricky in application than it is in theory.

Seeming like the best option is to melt and re-cast the copper into a column of proper OD and then drill the center ID to correct size. The I'd have a tube, which would still need to be 'paired off' into the individual washers. If my required thickness was 1mm, I'd lose a lot of copper to the scrap pile with each pass of a cutting tool. Proper blade on a compound miter saw could 'pair off' the washers but with each cut I would lose the width of the blade unless I collected all the copper 'saw dust' and re-melted it but that would be dicey. If I used cutting oil it would contaminate the copper.

For what it's worth, I've learned that all copper washers available are typically stamped.

My attempts at punching the copper with punches pictured further up in the thread haven't been pretty. The copper has to be backed up firmly (with steel) and once the punch breaks through the copper and strikes the steel, the punch dulls rapidly or shatters.

This is proving to be a bit of a riddle.

[corksil]

I guess the question at this point is "how to tool soft metal."

None of this stuff would be possible with lead, because it's far too soft to machine.

The right aluminum alloy would be easier to work with. Something a little softer than t6061 but no where near as soft as copper. Now I understand why CNC aluminum parts are so common to find; yet CNC copper is completely unheard of.

Copper melts around 1900*F but is highly ductile and maleable.
Aluminum around 1200*F but is much more brittle and responds well to cutting tools without deformation.

[Mechanikrazy]

Originally Posted by corksil

@Mechanikrazy -- widening an existing hole in a copper washer is a bugger to accomplish. The washer has to be held securely which cannot happen horizontally in a bench vise because the washer deforms when squeezed. I suppose I could try to clamp it vertically but even with a brand new sharp drill bit, cutting oil, and very high speed with light pressure -- the washer tries to bend sideways.

My attempts at punching the copper with punches pictured further up in the thread haven't been pretty. The copper has to be backed up firmly (with steel) and once the punch breaks through the copper and strikes the steel, the punch dulls rapidly or shatters.

This is proving to be a bit of a riddle.

Hope you find what you're looking for! Do you have a mill?

Instead of directly clamping the washer, I was imagining some kind of fixation. I haven't ever had a need for such specific washers, so haven't done this, so I am really just talking out of somewhere....

But I am imagining a square block of metal. Mill out a small recess slightly oversized for the washer, and of a smaller depth, so the washer sits above the surface. Tap holes, 3 or 4, on the edges of the washer recess to use set screws to really clamp down on the washer, so it won't rotate. Then you can just clamp the vise against the flat surfaces of the square block/holder, and mill out the ID to size.

[corksil]

I don't have a mill and I'm not familiar with the term but I'm liking your idea.

green would be angle of drill bit and location of washer between the blocks.

circles would be holes drilled in top block.

triangles would be tapped holes in lower block.

red lines would be clamping force applied by the four corner bolts etc.

This is proving to be quite a challenge. FWIW I need ~75 of these washers.. not sure if I mentioned that in the thread already or not.

[Mechanikrazy]

Originally Posted by corksil

I don't have a mill and I'm not familiar with the term but I'm liking your idea.

green would be angle of drill bit and location of washer between the blocks.

circles would be holes drilled in top block.

triangles would be tapped holes in lower block.

red lines would be clamping force applied by the four corner bolts etc.

This is proving to be quite a challenge. FWIW I need ~75 of these washers.. not sure if I mentioned that in the thread already or not.

Wow. 75! Definitely would make a holder. Haha. If the right setup could be found, I would imagine this should be about a minute a washer kind of a job. The most time consuming part will be tightening and loosening the screws to hold it together.

What tools are you using right now, if you don't mind me asking? Are you using a handtool, a drill press, or other?

A mill is basically a fancy drill press with a precisely moveable table for your part. With milling cutters, you can cut down into the material, as well as side to side.

Your latest drawing looks like it could work. If you create a sized recess on the bottom piece to retain the washer in place, it should be an easy job. Having the top plate would definitely be a better continuous fix than set screws.

I don't have any modeling software on my laptop anymore, but I'll see if I can whip up something by paper and pencil to send you.

[Mechanikrazy]

This is what was in my head.

Definitely doesn't need to be that thick of a block/holder. It was just what happened to flow from the pen. Haha.

P.S. Oops. Forgot the drill hole on the top piece you were envisioning, but yeah.

[Alex]

Project well underway?

[Skullz]

Brass or copper crush washers would be your best bet, but finding them with both a 6mm id and 8mm od will be impossible as there is not enough material to prevent a blow out.
M6 x 10 would be an easy enough size to score any amount of washers needed for your project.
They make both copper and brass crush washers.

http://www.ebay.com/sch/i.html?_from...shers&_sacat=0

[corksil]

Yeah things are moving forward. I ended up finding washers close to the proper size, machining them each slightly, and heat-treating them a bit.

So far they seem to be working. Thanks for all the info.

[Rifleman]

I know a guy who might be able to help.

pure copper used in high vacuum systems.

super soft.

[corksil]

Interesting. I have been very hesitant to share the details of this project openly because the internet can be a very cruel place. 95% of the replies would consist of "it will never work, you are an idiot" and the other 4% would probably be negative yet only slightly more constructive than negative. The final 1% of the replies would be the very thing I needed to hear to get this wrapped up and done. Then again, I'm hesitant to post the specifics because I don't have the time to wade through the negativity while trying not to get disheartened.

For now everything is assembled with copper. Lead was too soft. I believe there are alloys of lead and tin which could work but I don't have the time to set up a system of tools that would make me capable of smelting my own alloys. Maybe some day but for now this is really just a learning experience with a [hopefully] usable end result.

Do keep in touch.

[Rifleman]

well the guy that has the copper gaskets also cast his own bullets.

90% lead, 8% tin, 2% antimony. That's a pretty standard bullet formula.

let me know if you have any questions, I'll answer in the blind if need be

[Ducati999]

I realize you already have the required washers and your project is assembled. I just wanted to suggest should you need to manufacture any more washers, just clamp 2 steel washers together (of correct size) and put the copper in between then drill the hole. This will prevent the copper from distorting when or if the drill bit "catches" the copper and it will assure your drilling on center