>I am making reagent vessels [BrF5] out of 1" [25 mm] Kel-F rod.  Would
>anyone care to recommend an appropriate diameter for drilling it out?
>
>********************************
>Steve Nelson

Hi Steve,

In the past we have used a 12.5mm 1/2" diameter on [ 3/4" 19 mm] diameter
Kel-F rod leaving 3.5mm wall thickness.

The drill hole was bottomed with a long ball nose cutter to round out the
base of the holes (we do the same on Ni bombs) in an attempt to stop stress
fractures. The long ball nose cutter was made in-house by precisely silver
soldering a short ball nose mill cutter to a long piece of silver steel.  I
don't think you can buy the cutters long enough.

25mm 1" of solid rod was left at the bottom of the finger for extra strength.
There may an element of overkill in this design but we've never had a
failure of a Kel F finger.

Cheers
Joe Cali