U47-style bodies - who can make one?

[Skylar]

Skylar, one more design question.   ;D  Forgive me if I missed it earlier in the thread... but how do we afix the screens to the headbasket top band? 

I have several points to ask about that and the headbasket & mesh in general:  We'll use solder, presumably with a flame and flux like with soldering copper pipe to afix the mesh? 

I know there was some discussion about how solder and the various metals will accept nickel plating... will the stainless steel be solderable, and nickelable?   

Is the top dome a separate set of mesh from the cylindrical part below?  Attached separately? 

If so, I see there's just a tiny lip there on the top of the band (see photo above) to attach it to... is this how it's going to fit?  How does one cut the mesh(es) to align evenly along that rim, seems tricky... I suppose with a template to mash the mesh into place, then trim the excess with snips would work like a jiffy.  You planning something like that?

Is the entire headbasket going to be plated?  Or only the framing, not the mesh?

And finally, if I buy an assembled kit, may I request having the finest mesh omitted when the headbasket is assembled? In other words, just the two coarser meshes instead of all three.

Maybe I should have sent this by PM, but it might be useful info for others...
Thanks.

I'm going to try to answer all of your questions—not necessarily in order.


I am experimenting with ways to form & attach the mesh.
The originals were soldered.

Solder paste + oven may work.
Welding Rod (muggy weld) + flame/heat gun may be necessary instead or in addition to the above.

The mesh is two-part...a main cylindrical mesh & a bowl-shaped top mesh.
The brass headbasket rings are identical to the original with the exception that the bottom ring does not have the pattern switch hole, capsule plate holes are omitted as they're not needed, and the side holes are on 90° centers instead of 120° centers).
The mesh attaches to the headbasket rings via the "lip" that you see on the parts.


Here's one way it could work:

On the bottom ring's lip you would squeeze out a bead of solder paste from a syringe then affix the cylindrical mesh.
The top ring will require solder paste on the top and bottom of its lip.
The top ring would then be attached.
The bowl-shaped mesh is then fitted into the top ring.
Put a bead of paste on the cylindrical mesh seam and the opposite side.
Attach the vertical rails.
The whole thing then goes into an oven, the paste melts, done.
Then the whole assembly is plated (optionally bead-blasted first).

Of course...
The vertical rails may need to be muggy welded instead of solder pasted before the mesh is attached.
It looks like that's how FLEA does it.
This is where some experimentation is going to have to happen.



The mesh I plan to use is all-brass.
Stainless requires high temperatures (torch) & special flux to weld.
Stainless is nickel plate-able but may require a special pre-plate before it will accept the nickel.
I don't plan on using any stainless steel.


The best way to form the mesh is all three layers at once with a punch press, as we saw in the Neumann "how it's made" video.
This requires custom tooling.
I have already designed the punch & die set that will form & cut the top bowl-shaped mesh using a simple 20-ton arbor press.

I do not know how much this tooling is going to cost yet, but it won't be cheap.
Right now, I'm also looking into having the headbaskets+mesh assembled turn-key, so that I don't have to worry about all of this.
The prices I have received for this before were REALLY high.
BUT, those early prices included the machining of the parts, which the mesh fab shops were probably not capable of doing cheaply.
Now that I've got a good source for the parts, I can send them to a mesh fab place, and hopefully the assembly prices will be more reasonable.



For one-offs, just shape the mesh by hand with a doorknob, then trim as needed.


¡Wow, this is almost becoming a full-time endeavor!
No worries, though; I am super motivated on this project!

 

[ioaudio]

you could look into inductive heating for the soldering process.
keep up the good work skylar.

-max
edit: stupid suggestion, works only with magnetic materials
edit2: works with HF eddy currents also in non ferromagnetic material so it still could work.
note to self: read your links before posting

 

[rodabod]

STS-47 - 25€

Are Thiersch's M7s drilled to accept this mount then?

Thiersch's STW-7 (his M7 capsule) is not drilled at all.
It's held into the STS-7 mount through pressure applied by 3 set screws.

Thanks for that. I was wondering..... Well, maybe it will be suitable for Dale's M7 capsules then.

 

[e.oelberg]

Skylar,

couldn't the tool be made out of wood, with a turnery machine, the from and the stamper would then be fixed into a drilling stand ?

nicholas

 

[Skylar]

Skylar,

couldn't the tool be made out of wood, with a turnery machine, the from and the stamper would then be fixed into a drilling stand ?

nicholas

The tool must form and shear 3 layers of brass mesh in one action.
To do this, you must have an extremely hard tool.
This is why the tool should be made of something like A2 tool steel.
Mild steel will wear down.
Aluminum will wear down quicker.
Wood will not shear but may be able to form, and, even then, it would wear down after a few formations.

For a one or two-off, you could sculpt a wooden punch/die set to form the mesh around.
Then you would have to use snips or a rotary cut-off wheel to cut the mesh to size after forming.

To do 200+ quantity, proper tooling is needed.

 

[tommypiper]

Skylar, thanks.  Wow, it's turning into a whole cottage industry of its own.  I imagine you'll be able to continually manufacture bodies and sell them after our group buy, if you want to.  Particularly with the industrial basket press you describe.  Once it's up and running you'll be able to keep going.  And I can see some microphone makers would love to have a supply of these; you may find you have quite a market for them beyond our forum...   

I've always wondered why an Asian factory hasn't come out with a half decent U47 style body  yet -- it seems part of the answer is that tricky headbasket mesh shaping and soldering, particularly with the narrow top band.  (This is a pet peeve of mine on so many other Chinese mics which are either dead ugly or have a very wide top band.) 

FWI, I think I'll be able to build the headbasket by hand with the parts in the unassembled kit.  Thanks for the exhaustive explanation.  Looks doable by hand!

My last question, if I buy a pre-assembled body, may I request having the fine inner mesh omitted when the headbasket is assembled? In other words, just the two coarser meshes instead of all three?  (This was one reason I was interested to buy an unassembled kit, to reduce mesh layers, and I'm wondering if this will be an option?)

 

[Skylar]

My last question, if I buy a pre-assembled body, may I request having the fine inner mesh omitted when the headbasket is assembled? In other words, just the two coarser meshes instead of all three?  (This was one reason I was interested to buy an unassembled kit, to reduce mesh layers, and I'm wondering if this will be an option?)

Sorry, I forgot to answer that one.

The answer is: I don't know.
If I have the headbaskets turn-keyed, then most likely no.
If I do them myself, I don't see why not, but then I start getting into tricky territory if lots of people are requesting custom mesh configs.
These headbaskets may take a lot of labor, so allowing custom mesh requests will slow down the whole process, and at that point, I would probably be forced to charge more $$$.
I'm trying to keep the cost as low as humanly possible.

 

[Skylar]

So another couple weeks probably of wait time?

I'm waiting to hear back from the shop on time-frame for the second round of protos.

 

[giantbenny]

hi guys, hi skylar.  Just thought i'd jump in and chat about the grills.  the easiest and cheapest way to get them formed is by spinning.  i you contact a metal spinner, he will be able to build the complete head grill for about 20-25usd for the completed unit, all you have to do then is plate it.  Just a thought.

cheers.

ben

 

[Skylar]

hi guys, hi skylar.  Just thought i'd jump in and chat about the grills.  the easiest and cheapest way to get them formed is by spinning.  i you contact a metal spinner, he will be able to build the complete head grill for about 20-25usd for the completed unit, all you have to do then is plate it.  Just a thought.

cheers.

ben

Ben, thanks for the tip!
I'm a little confused, though...
Are you talking about the mesh being spun?

 

[Gus]

I don't understand how you could spin a grill.  Metal spinning forms/stretches sheet metal over a spinning form.  I would think the mesh would become very deformed if spun.

 

[Skylar]

I don't understand how you could spin a grill.  Metal spinning forms/stretches sheet metal over a spinning form.  I would think the mesh would become very deformed if spun.

Yeah, I am confused as to what exactly Ben is talking about...

 

[Skylar]

Second round of prototypes coming soon...
probably this coming week.

Stay Tuned.

 

[stitch-o]

Stay Tuned.

which station is the broadcast on?

 

[Skylar]

THIS STATION!

2nd round of protos are in the mail...I should see them in the next couple of days.

 

[peterh]

Hopefully this one is not refered too much to:

How a Neumann U87 microphone is manufactured: http://www.youtube.com/watch?v=cvtjHhtxmpI

Cheers,
              Peter

 

[klaus2you]

Wahoo , super nice video!!!

Thank you for posting this here.

 

[MagnetoSound]

Hopefully this one is not refered too much to:

How a Neumann U87 microphone is manufactured: http://www.youtube.com/watch?v=cvtjHhtxmpI

OT, but one annoying thing: can someone explain how they get away with using the words 'sodder', 'soddered' and 'sodder paste' in this video?

Obviously it means 'solder', but how did it come about? No slang dictionary that I can find recognizes it at all ... WTF?

 

[Skylar]

That's how we pronounce it in the U.S.

According to Merriam-Webster, both pronunciations are acceptable.

http://www.merriam-webster.com/dictionary/solder

 

[Emperor-TK]

I guess "sodder" implies something completely different in the UK. 
Based on where I live, I still refuse to accept that "fag" is an OK word for a cigarette.