According to McMaster Carr:

"The most formable brass we offer, 260 offers better weldability than
300 series brass but it’s not as machinable. Sometimes called cartridge
brass, it's commonly used for ammunition casings, radiator components,
and decorative door hardware."

Any tips for machining 260 brass? Well other than throw it away and buy
some 360 brass. 360 brass is a dream to machine.

Yesterday I was trying to machine some "260" and it whooped me. (My
best guess is it was 260 brass.) I was embarrassed. I was trying to
help a guy out who wants some brass lettering in fancy fonts. I tried
the glue and tape method. 1/32 and mills programmed for "brass" broke
very quickly. 1/16 end mills held up, but the brass looked like I had
hacked through with a bush knife. I also had some issues with pickup
which was expected. I was using standard end mills. I didn't even
think of using down cut mills because I've never had any problem with
brass ever. Even the little Harbor Freight mini lathe would blow
through it like a dream. Obviously I never cut 260 brass before.

Before somebody iterates the sentiment to throw it away and buy some
360... I looked a little bit. It seems 260 brass, 510 bronze, and
copper are the readily available stock thin enough for the application.
I already know copper is terrible to machine. 510 bronze makes no claim
to any machinability at all. 510 is also a crazy step up in price.

The guy I was working with brought the stuff we were working with
yesterday. He called it jewelers bronze, but it looked like brass and
the cost he claimed was in line with the cost of 260 ultra formable
brass sheet.

I think sandwich cutting is out. I have done sandwich machining before.
In fact I posted a video years ago machining paper key phone keypad
templates on my Taig with custom made sandwich plates. Paper is worse
than copper. Sandwich cutting terrible material is fine if you are
removing pockets, but in this case we want to retain the cutouts. Not
waste them away.

So far the only thing I have come up with is a little more care with the
glue and tape method, and switching to straight flute or down cut mills.

Yes I have thought of laser. I don't have a laser... well I might not
have a laser. I was given one a few years ago with enough power to
slowly mark wood. I doubt it would even make a visible mark in brass if
I left it in one spot all day. I don't recall if I threw it away yet or
if I just thought about it. I have contacted a few other people, and
most have said either the laser they have is not adequate for cutting
brass, or they are not interested in jobs of just a few hundred bucks a
run.

--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist

--
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On 4/14/2023 10:37 AM, Bob La Londe wrote:
> According to McMaster Carr:
>
> "The most formable brass we offer, 260 offers better weldability than
> 300 series brass but it’s not as machinable. Sometimes called cartridge
> brass, it's commonly used for ammunition casings, radiator components,
> and decorative door hardware."
>
> Any tips for machining 260 brass? Well other than throw it away and buy
> some 360 brass.  360 brass is a dream to machine.
>
> Yesterday I was trying to machine some "260" and it whooped me.  (My
> best guess is it was 260 brass.)  I was embarrassed.  I was trying to
> help a guy out who wants some brass lettering in fancy fonts.  I tried
> the glue and tape method. 1/32 and mills programmed for "brass" broke
> very quickly.  1/16 end mills held up, but the brass looked like I had
> hacked through with a bush knife. I also had some issues with pickup
> which was expected.  I was using standard end mills.  I didn't even
> think of using down cut mills because I've never had any problem with
> brass ever.  Even the little Harbor Freight mini lathe would blow
> through it like a dream. Obviously I never cut 260 brass before.
>

I don't know Bob . I melted some cartridges and cast them into
cylinder molds to make height adjustment nuts for my QCTP tool holders .
It machined just fine on the lathe . The finish wasn't spectacular but
it wasn't gummy of grabby .
--
Snag
"You can lead a dummy to facts
but you can't make him think."

On 4/14/2023 12:07 PM, Snag wrote:
> On 4/14/2023 10:37 AM, Bob La Londe wrote:
>> According to McMaster Carr:
>>
>> "The most formable brass we offer, 260 offers better weldability than
>> 300 series brass but it’s not as machinable. Sometimes called
>> cartridge brass, it's commonly used for ammunition casings, radiator
>> components, and decorative door hardware."
>>
>> Any tips for machining 260 brass? Well other than throw it away and
>> buy some 360 brass.  360 brass is a dream to machine.
>>
>> Yesterday I was trying to machine some "260" and it whooped me.  (My
>> best guess is it was 260 brass.)  I was embarrassed.  I was trying to
>> help a guy out who wants some brass lettering in fancy fonts.  I tried
>> the glue and tape method. 1/32 and mills programmed for "brass" broke
>> very quickly.  1/16 end mills held up, but the brass looked like I had
>> hacked through with a bush knife. I also had some issues with pickup
>> which was expected.  I was using standard end mills.  I didn't even
>> think of using down cut mills because I've never had any problem with
>> brass ever.  Even the little Harbor Freight mini lathe would blow
>> through it like a dream. Obviously I never cut 260 brass before.
>>
>
>
>   I don't know Bob . I melted some cartridges and cast them into
> cylinder molds to make height adjustment nuts for my QCTP tool holders .
> It machined just fine on the lathe . The finish wasn't spectacular but
> it wasn't gummy of grabby .

Generally I have found thicker material machines better than thinner
material, but the tearing was real. Its also possible the structure of
the metal may have been better for machining after casting... and while
260 is sometimes called cartridge brass that's doesn't mean all
cartridge cases are 260. I have ordered some down cut mills to try
again with the sheet glued directly to the substrate I'm hoping by
forcing the chip downward into the stock below it will shear better, and
of course it will have less likelihood of been lifted off the glue with
a down force cut.

I also ordered about $100 worth of 260 sheet to play with.

--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist

--
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On 4/15/2023 11:41 AM, Bob La Londe wrote:
> On 4/14/2023 12:07 PM, Snag wrote:
>> On 4/14/2023 10:37 AM, Bob La Londe wrote:
>>> According to McMaster Carr:
>>>
>>> "The most formable brass we offer, 260 offers better weldability than
>>> 300 series brass but it’s not as machinable. Sometimes called
>>> cartridge brass, it's commonly used for ammunition casings, radiator
>>> components, and decorative door hardware."
>>>
>>> Any tips for machining 260 brass? Well other than throw it away and
>>> buy some 360 brass.  360 brass is a dream to machine.
>>>
>>> Yesterday I was trying to machine some "260" and it whooped me.  (My
>>> best guess is it was 260 brass.)  I was embarrassed.  I was trying to
>>> help a guy out who wants some brass lettering in fancy fonts.  I
>>> tried the glue and tape method. 1/32 and mills programmed for "brass"
>>> broke very quickly.  1/16 end mills held up, but the brass looked
>>> like I had hacked through with a bush knife. I also had some issues
>>> with pickup which was expected.  I was using standard end mills.  I
>>> didn't even think of using down cut mills because I've never had any
>>> problem with brass ever.  Even the little Harbor Freight mini lathe
>>> would blow through it like a dream. Obviously I never cut 260 brass
>>> before.
>>>
>>
>>
>>    I don't know Bob . I melted some cartridges and cast them into
>> cylinder molds to make height adjustment nuts for my QCTP tool holders
>> . It machined just fine on the lathe . The finish wasn't spectacular
>> but it wasn't gummy of grabby .
>
>
> Generally I have found thicker material machines better than thinner
> material, but the tearing was real.  Its also possible the structure of
> the metal may have been better for machining after casting... and while
> 260 is sometimes called cartridge brass that's doesn't mean all
> cartridge cases are 260.  I have ordered some down cut mills to try
> again with the sheet glued directly to the substrate I'm hoping by
> forcing the chip downward into the stock below it will shear better, and
> of course it will have less likelihood of been lifted off the glue with
> a down force cut.
>
> I also ordered about $100 worth of 260 sheet to play with.
>
>

I think you're on the right track with the down cut end mills . What
is your substrate ? I hear you've got a lot of aluminum around ...
--
Snag
"You can lead a dummy to facts
but you can't make him think."

On 4/15/2023 3:24 PM, Snag wrote:
> On 4/15/2023 11:41 AM, Bob La Londe wrote:
>> On 4/14/2023 12:07 PM, Snag wrote:
>>> On 4/14/2023 10:37 AM, Bob La Londe wrote:
>>>> According to McMaster Carr:
>>>>
>>>> "The most formable brass we offer, 260 offers better weldability
>>>> than 300 series brass but it’s not as machinable. Sometimes called
>>>> cartridge brass, it's commonly used for ammunition casings, radiator
>>>> components, and decorative door hardware."
>>>>
>>>> Any tips for machining 260 brass? Well other than throw it away and
>>>> buy some 360 brass.  360 brass is a dream to machine.
>>>>
>>>> Yesterday I was trying to machine some "260" and it whooped me.  (My
>>>> best guess is it was 260 brass.)  I was embarrassed.  I was trying
>>>> to help a guy out who wants some brass lettering in fancy fonts.  I
>>>> tried the glue and tape method. 1/32 and mills programmed for
>>>> "brass" broke very quickly.  1/16 end mills held up, but the brass
>>>> looked like I had hacked through with a bush knife. I also had some
>>>> issues with pickup which was expected.  I was using standard end
>>>> mills.  I didn't even think of using down cut mills because I've
>>>> never had any problem with brass ever.  Even the little Harbor
>>>> Freight mini lathe would blow through it like a dream. Obviously I
>>>> never cut 260 brass before.
>>>>
>>>
>>>
>>>    I don't know Bob . I melted some cartridges and cast them into
>>> cylinder molds to make height adjustment nuts for my QCTP tool
>>> holders . It machined just fine on the lathe . The finish wasn't
>>> spectacular but it wasn't gummy of grabby .
>>
>>
>> Generally I have found thicker material machines better than thinner
>> material, but the tearing was real.  Its also possible the structure
>> of the metal may have been better for machining after casting... and
>> while 260 is sometimes called cartridge brass that's doesn't mean all
>> cartridge cases are 260.  I have ordered some down cut mills to try
>> again with the sheet glued directly to the substrate I'm hoping by
>> forcing the chip downward into the stock below it will shear better,
>> and of course it will have less likelihood of been lifted off the glue
>> with a down force cut.
>>
>> I also ordered about $100 worth of 260 sheet to play with.
>>
>>
>
>   I think you're on the right track with the down cut end mills . What
> is your substrate ? I hear you've got a lot of aluminum around ...

Somebody in my shop was looking at a tool cart over flowing with metal
today and said, "Wow, Look at at all those molds."

In disgust I replied, "Yeah. Look at all that scrap metal. Those are
all failures."

I use aluminum for sacrificial backers all the time. I like to use the
glue and tape method, but I think for my next try at this I'll just glue
direct so its a more rigid setup. I think the parts are narrow enough I
may be able to dissolve the glue with an acetone bath quickly enough.

--
Bob La Londe
CNC Molds N Stuff

--
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"Bob La Londe" wrote in message news:u1f9j3$26vq1$1@dont-email.me...
.....
I use aluminum for sacrificial backers all the time. I like to use the
glue and tape method, but I think for my next try at this I'll just glue
direct so its a more rigid setup. I think the parts are narrow enough I
may be able to dissolve the glue with an acetone bath quickly enough.

Bob La Londe
CNC Molds N Stuff

---------------------

https://www.woodsmith.com/article/episode-006-metal-inlays/

Hide glue sets up very rigid but melts below the boiling point, and washes
off with water.

In Jr High shop class we were taught to attach bowl turning blanks to the
backing block with hide glue, with a sheet of newspaper between the bowl and
the block. After turning the bowl it could be separated cleanly without
damaging the wood with heat or water, by tapping a chisel blade into the
joint. It would separate within the paper, which could then be washed off.

I know a wood turner who turns bowls from softer green wood and dries them
in a microwave afterwards, with good results.