The making of.... a coil former set
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Some photo's may be clicked to get a larger one! Last update: 2012-11-01
   
Before a coil former set is put in a plastic bag and shipped to your home, some work has to be done.

The material comes in 117 cm long tubes or rods and has to be changed in something you can use.


Information on Paxolin

In all kinds of publications around Paraset one encounters the mysterious name Paxolin. Paxolin is (was) merely a brand name that became synonym for a smelly, brown insulating material. Nowadays this brand no longer exists, as far as I know but brands like Tufnol and Novotex do. In the old days, over here in The Netherlands we called it “Pertinax”.

What kind of material is it? The basis is Phenol Formaldehyde Resin (PF) that is applied either to paper or to textile. Soaked and pressed under high temperature, similar to Bakelite. For printed circuit board (the old fashioned brown type) and isolation purposes paper is used (that is why PCB's easily break), for more heavy duty applications the textile variant is used. You can imagine that the textile does the same as the iron does in concrete, it enhances the strength. The textile type is used, amongst many others, in the sailboat environment: wheels in pulley blocks and alike. PF is tough, has good electrical qualities, is easy to saw, drill, mill. It has a tight surface so it can withstand harsh environments. If you want to know more of this historical stuff, follow this link to an informative Wiki-page: http://en.wikipedia.org/wiki/Phenol_formaldehyde_resin.

   
Coil former for TX coil

On the right hand side the coil former I sell. On the left is the same former, but sanded with 800 emery paper and a drop of oil.
Material: textile fibre and phenol formaldehyde resin

Sizes:
Diameter, outside: 38 mm
Diameter, inside: 32 mm
Length: 68 mm
State: machine cut, ends sanded, unpolished, no holes drilled.

   
Stand for TX coil

Material: paper and formaldehyde resin

Sizes:
Diameter, outside: 8 mm
Length: 6 mm
State: machine cut, unpolished, edges sanded, drilled through at 3 mm. The hole will fit M3 and BA6, which measures 2,7 mm. The buyer will have to file a hollow to fit the TX coil curve.

   
Coil former for RX coil

Material: textile fibre and phenol formaldehyde resin

Sizes:
Diameter, outside: 25 mm
Diameter, inside: 22 mm
Length: 35 mm
State: machine cut, ends sanded, unpolished, no holes drilled.

   
Core for RX coil

Material: textile fibre and formaldehyde resin

Sizes:
Diameter, outside: 6 mm
Length: 34 mm
State: machine cut, unpolished, edges sanded, drilled through at 2,4 mm (will fit M3/BA6 thread).

   
Cover for RX coil

Material: paper fibre and formaldehyde resin

Sizes:
Diameter, outside: 25 mm
Length: 3 mm
State: machine cut, unpolished, edges sanded, drilled through at 3 mm. The hole will fit M3 and BA6, which measures 2,7 mm.

   
Stands for pilot light (set of 2)

Material: textile fibre and formaldehyde resin

Sizes:
Diameter, outside: 6 mm
Length: 34 mm
State: machine cut, unpolished, edges sanded, drilled through at 2,4 mm (will fit M3/BA6 thread)

   
Centre drilling tx-coil stand
Every tx-coil stand was centred and than drilled at 3 mm.
Centre drilling rx/pilot light stand
Every rx-coil stand was centred and than drilled at 2,4 mm.  Due to the material one has to centre and drill from both sides. Otherwise, the powder clogs up the drill and causes the stand to break.
 2,4 mm drilling rx/pilot light stand

The rx-coil cover was centred and drilled at 3 mm.

   
Set, containing TX + Rx coilformers, RX coil cover and 3 stands and drawing / technical details coils

Price: €  25,00

Coil formers are NOT polished. Set contains TX + Rx coil formers, RX coil cover, 3 stands and drawing / technical details.

 

2012-03-01: I made new sets, so there is stock again.


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