[Amps] nylon screws in chimneys

[John T. M. Lyles]

I think the nylon screws might work if they remain small, and don't 
reside in regions where intense fields would cross, such as just in a 
small space between hot and ground conductors. In a chimney, would 
place only a few of them, keep them small (4-40 thread size) and 
don't put any metal washers on them. If you figure the chimney as a 
solid dielectric, and put a couple of pertubations in it, with higher 
K than PTFE (K=2.1), the voltage division in the screws is almost 
like the solid sheet.

If that doesn't work out, try screws cut from Teflon (weak, but who 
cares in this application) or even try polysulfone material, used in 
medical devices. It has good RF and HV properties and is available in 
rod stock to be threaded. One trade name is Thermalux*.
73
John
K5PRO

>
>  > 3.  Make from sheet and secure with NYLON screws and nuts.
>
>I've always been dubious of nylon in high rf fields, although I couldn't give
>examples of why.