Carnhill 10468 Screw size [email protected]$%#!
« on: June 18, 2007, 08:26:29 PM »
Pretty inane question, but does anyone know the type of screw that are on these xfmrs?  It seems like an odd size since I have tried M3(.6mm pitch) and 4-40.


madriaanse

Carnhill 10468 Screw size [email protected]$%#!
« Reply #1 on: June 19, 2007, 01:09:53 AM »
It's some weird British Imperial thread that's pretty well impossible to get; contact Carnhill and they'll mail you some screws. I believe they only recently started shipping 10468 with the screws included. If you're impatient you can also drill and tap the holes to 6-32.

M.

Carnhill 10468 Screw size [email protected]$%#!
« Reply #2 on: June 19, 2007, 01:29:40 AM »
Thanks, i thought it was somethign wierd like a .8 mm pitch and 3 mm diameter.  The 3mm's we have here are .6 mm pitch standard IIRC.


I was hoping to get a longer screw to clamp down to a PCB since these are too short.

-I was weary on tapping the XFMR for fear of the shavings falling into the windings and messing things up ....

-Do you think it's safe?  Isolated?

dissonantstring

Carnhill 10468 Screw size [email protected]$%#!
« Reply #3 on: June 19, 2007, 12:08:00 PM »
hi charlie,
i'm pretty sure the screw threadings on the 10468 are isolated.  all the white potting on the carnhill version (or green/yellow on originals) is surrounding the actual coil (at least on mine they are) and i believe they are isolating it from the mounting thread/part/whatever.  

joel mentioned that he just taps a new threading (4-40 IIRC) for more readily available screw sizes.  i don't think you have to worry unless you crack open the potting, heat up the coil, remove all the gunk and basically do a CJ hack! :wink: you should make sure that whatever threading size you go with it is just slightly larger than it is now.

maybe you could ohm out the threading with reference to pins 2-5, 7 & 10 and make sure they are not shorting to GND (which they shouldn't be) before and after to make sure.
regards,
grant

madriaanse

Carnhill 10468 Screw size [email protected]$%#!
« Reply #4 on: June 19, 2007, 01:36:56 PM »
Yeah, it's no problem to drill and tap the bottom holes to 6-32; I've done it plenty of times (before Carnhill mailed me the correct screws.) Just don't drill through the screws that hold the metal wrapper. I have a few extra original screws I can send you; PM me if you're interested.

M.

Carnhill 10468 Screw size [email protected]$%#!
« Reply #5 on: June 19, 2007, 02:27:51 PM »
Thanks Grant & M.  It's good to know that I need to do a CJ hack to mess it up :-)

I am fine M, thanks for the offer, but I have the original screws which I will put in a safe place now that I know they are odd fellas.

a-tapping I will go......

CJ

Carnhill 10468 Screw size [email protected]$%#!
« Reply #6 on: June 19, 2007, 06:48:19 PM »
there should be a thread with many pictures.
which screws, the philister heads that bolt it down, or the side cover hardware?
6-32 seems large, 440, if you have enough meat left.
don't let your meat loaf.
brass square stock in there, requires different tapping technique, usually a larger drill for Al, copper, brass, all your soft metals.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

tommypiper

Carnhill 10468 Screw size [email protected]$%#!
« Reply #7 on: June 19, 2007, 07:34:12 PM »
CJ, he's talking about the mounting screws that bolt it down.  Not the side cover screws.

Which is better, 6-32, or 4-40?

Maybe we need a Carnhill group buy for screws.
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..

Carnhill 10468 Screw size [email protected]$%#!
« Reply #8 on: June 19, 2007, 08:33:48 PM »
Quote from: "tommypiper"
Maybe we need a Carnhill group buy for screws.

 :grin:

Thanks CJ, it looks like I'm  pretty safe as long as that white stuff is all over the inside.  the thing is that I need longer screws to clamp it to a pcb.  If it's a toos up between 4--40 or 6-32, I'll test it out on the top.

This was the pic



deffinitley no this pic

tomelectro

Carnhill 10468 Screw size [email protected]$%#!
« Reply #9 on: June 20, 2007, 01:12:31 AM »
I just checked a Carnhill Mic x-former I've got lying around, and the threads look to be 4-48 (#4 fine thread).  Not as ubiquitous as 4-40, but not impossible to find. I usually order them from McMaster-Carr.  Also handy for old Neve modules.


Carnhill 10468 Screw size [email protected]$%#!
« Reply #10 on: June 20, 2007, 01:48:50 AM »
does anyone have any 48 pitch bolts or gauge to test this theory?  I just  tried but my gauge only goes to 40 as most do. 4-48 bolts are steep, $16 for 100 as opposed to less than $2 for reg 4-40    :shock:  :(

tomelectro

Carnhill 10468 Screw size [email protected]$%#!
« Reply #11 on: June 20, 2007, 04:20:40 PM »
A 4-48 screw fit perfectly in my transformer (can't remember the part number, but it looks like the dissected one pictured above. It was for a Chandler Mic input).  PM me and I'll send you a couple screws.  They will be flat-head, and probably too long, but you can check the thread.

Carnhill 10468 Screw size [email protected]$%#!
« Reply #12 on: June 20, 2007, 05:12:03 PM »
Tom, thanks for your generosity.  How long are your 4-48's? I need around  3/8" and 6 of them.  londer is fine, but if it's too many I can order easily since mcmaster is in NJ and takes a day to arrive.

Group buy 3/8" machine screws from mcmaster :green:
I found Phillisnter $9.xx for 50
and round slot head $16.xx for 100

Carnhill 10468 Screw size [email protected]$%#!
« Reply #13 on: June 20, 2007, 05:24:08 PM »
actually slotted 1/2" is $10.xx for 100
-Since that brass thread runs through to the other end, I guess 1/2" is an OK length.
-uh, nix  that.... the case screws block the path.

CJ

Carnhill 10468 Screw size [email protected]$%#!
« Reply #14 on: June 20, 2007, 05:42:13 PM »
hope it's not a winty.  :shock:
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Carnhill 10468 Screw size [email protected]$%#!
« Reply #15 on: June 20, 2007, 05:47:16 PM »
Quote from: "CJ"
hope it's not a winty.  :shock:


HUH!? :?

CJ

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

dissonantstring

Carnhill 10468 Screw size [email protected]$%#!
« Reply #17 on: June 20, 2007, 06:40:14 PM »
oh boy CJ!   :grin:
thanks for bringing that thread up again.  i still laugh while reading it!

BTW, was there ever a solution/resolution for the pin swap on the custom carnhill 10468 inputs we got in Joel's group buy?  

cheers,
grant

tomelectro

Carnhill 10468 Screw size [email protected]$%#!
« Reply #18 on: June 20, 2007, 06:55:46 PM »
I  have a bunch of 1/2" flat-head (thread length is a touch over 3/8"), but that's the shortest I have. Unfortunately, I dont' have any round head or pan head screws, just the flat head (countersunk). I could easily send a half dozen if you like, just send me a PM with your address.

What's a Winty?  :?:

tommypiper

Carnhill 10468 Screw size [email protected]$%#!
« Reply #19 on: June 20, 2007, 08:56:31 PM »
I'll be curious to see if the 48 thread works.  You could send me a pair for testing.  PM me.  

The original is not a 48 thread.  But maybe a 48 thread works in it.  The original is a unique, obsolete British standard, not imperial, not metric.
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..


 

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