Guyz,
I measured the diameter of two 850 coils and came up with a
nominal figure of .125". Mind you, these measurements were
taken with very poor equipment.
I forwarded photos to Gary of one 850 that I rebuilt years ago.
The supporting arms of the small diameter (wire) coil were two-piece.
A flat 1/4" thick piece about 1/2" in width, and a small 1/4" width
piece that fit into a slot cut in the wider piece. All this is said while
realizing
that these were probably early models. Later models, as I recall, used
melted
rod to hold the whole mess together.
The 1/4" width pieces were initially notched on a table saw, and the
work piece was quite large. Later the large piece was cut in small strips.
Worked very well for me.
If anyone would like to see the parts, please advise and I will send photos.
Bill Wylde, K9WXR
-----Original Message-----
From: Carl
Sent: Saturday, October 27, 2012 8:29 AM
To: Paul Kraemer ; amps@contesting.com
Subject: Re: [Amps] B&W 850A Repair
Silver prices went up, plating thickness went down (-;
And #8 wire has long been a standard at .1285. Maybe your NIST boys are
using Chinese instruments.......
Thats my story and Im sticking to it.
Carl
KM1H
----- Original Message -----
From: "Paul Kraemer" <elespe@lisco.com>
To: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>
Sent: Friday, October 26, 2012 8:57 PM
Subject: Re: [Amps] B&W 850A Repair
And I measure it at 0.1245" to 0.1255"
Our calipers are maintained by a lab using NIST standards and they were
recently certified
Customer requirement---they pay for it---we enjoy the benefits
Potato potahto, call it an 1/8" down here in the stix
Paul K0UYA
----- Original Message -----
From: "Carl" <km1h@jeremy.mv.com>
To: "Paul Kraemer" <elespe@lisco.com>; <amps@contesting.com>
Sent: Friday, October 26, 2012 7:04 PM
Subject: Re: [Amps] B&W 850A Repair
I measure the wire at .1325 which equates to #8 wire with the plating.
Carl
KM1H
----- Original Message -----
From: "Paul Kraemer" <elespe@lisco.com>
To: "Gary H. Harmon, Jr." <gharmon@idworld.net>; <amps@contesting.com>
Sent: Friday, October 26, 2012 6:57 PM
Subject: Re: [Amps] B&W 850A Repair
Gary
No support except the back end.
Scaling "up" from a complete 851 (500w) the bars on the 851 are 5/16"
wide with 1/8" material below the coil
Total thickness is the 1/8" plus wire diameter plus another 1/16".
The top is melted to anchor the turns
For the 850A that suggests that the bars need to be 3/8" wide by at
least 1/8" below the wire + the wire + another 1/6" (or more ) above the
turns.
I would suggest a minimum of 3/8" square bars---or even up to 1/2"
square since the wire diameter is a hefty 1/8"
Get some 3/8" or 1/2" stock from McMaster Carr and start notching with a
fine tooth band saw or jig (scroll) saw.
The notch spacing is linear over the approximate 3 1/4" length of the
coil
McMasterCarr doesn't list Lexan but this is similar
http://www.mcmaster.com/#polycarbonate-sheets/=jw6q79
If you can find actual Lexan it is best. Does not shatter or chip.
Extremely strong and easy to work. It is used in bulletproof glass
windows.
Have fun cutting all those notches! Clamp the bars together and do 4 at
once.
Paul K0UYA
----- Original Message -----
From: "Gary H. Harmon, Jr." <gharmon@idworld.net>
To: <amps@contesting.com>
Sent: Friday, October 26, 2012 3:07 PM
Subject: [Amps] B&W 850A Repair
I need to replace the 4 plastic coil supports on my 850A band switching
coil
assembly. I have no pieces to measure so I need to know the width,
thickness and length of the four pieces. Is there some sort of support
of
the four pieces at the ends inside the coil or is the only fastener
where
they bolt to the L-shaped brackets connected to the front of the
assembly?
Any suggestions on how to fasten the coils turns to the strips?
Vr,
Gary H. Harmon, Jr. - K5JWK
6003 Archwood
San Antonio, TX 78239-1504
210.657.1549h / 210.884.6926c
"Retirement means every day is a Saturday except Sunday".
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