Need 6-32 x 4" brass screws for UR64/40/20-3F3 core set

[Yzordderrex]

I need to find a source for 4" brass screws to bolt my cores
together. Seems I go through this exercise every few years, so I know
they exist. My purchasing agent tells me he can get stainless but
I've only used brass.

thanks
Bob
N9NEO

 

[Neon John]

I need to find a source for 4" brass screws to bolt my cores
together. Seems I go through this exercise every few years, so I know
they exist. My purchasing agent tells me he can get stainless but
I've only used brass.

We get ours from McMaster-Carr

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address

 

[whit3rd]

Why not use the stainless?

If there's any flux leakage, brass (diamagnetic) doesn't become
an important part of the magnetic circuit, while stainless (ferromagnetic) does.
Another good diamagnetic material is nickel silver (stronger than brass) which
one sees in lots of old meter movements.

 

[Tim Williams]

If there's any flux leakage, brass (diamagnetic) doesn't become
an important part of the magnetic circuit, while stainless
(ferromagnetic) does.
Another good diamagnetic material is nickel silver (stronger than brass)
which
one sees in lots of old meter movements.

AISI 304 is very nearly nonmagnetic (depending on hardness; permeability
is single digits, near 1 in any case), and also has higher resistance than
other metals (if any flux wants to go through it, it's welcome to; there's
little eddy current stopping it).

Surrounded by a massive block of ferrite, the thread material doesn't
matter.

Now... you didn't mention if this is gapped. If it is, even brass and
copper will heat up, because the fringing in the gap is quite intense.
Gapped cores need external clips (away from the gaps, or on the opposite
side of a singly-gapped core).

As for all-thread, seconded.

Tim

 

[George Herold]

If there's any flux leakage, brass (diamagnetic) doesn't become

I've got a bag full of magnetic 1/4-20 brass screws.
I can pick up a few of them with a strong magnet.
George H.

 

[josephkk]

Good stainless screws are nonmagnetic or slightly magnetic. Should be
OK.

No, JL. It depends on the particular SS involved, some are highly
ferromagnetic, some are almost diamagnetic, most are in between.

?-/