[timoteus]

What are the shaft diameters on the Seiden switches?  Are they 1/4" or metric?  Also, are they full round stock or flat-sided to accept a set screw?

Just trying to narrow down my options on knob selection.

[John Chapman]

Hello!

The Seiden switches have a 6mm shaft diam. When used in a kit with the remote control option there is a shaft extension that ends up as 1/4" diam and I drill out the knobs for the kits for 1/4" here for those kits.

The 6mm is quite close in size to 1/4". The shaft is round but a set screw seems to hold fine to the shaft. The only problem with a flat (and it may be why they have not used one) is that you can then not adjust the rotation of the knob to line up a pointer on the knob with front panel chassis markings - if there are any.

Please let me know if you need any more info!

Many Thanks!

John Chapman
www.bentaudio.com

[DrM]

Hi,
  Note however, that if you do any significant shaft exension, the slight mismatch in diameters will cause trouble. I have my Seiden in the back of my preamp with a 8" extension. At first, turning the volume control caused the switch and mounting bracket to twist around a lot. I didn't like that for such an expensive switch, so I added a flexible shaft coupler between them, which took up the extra "play."

  I was suprised at what a difference the small mismatch made, which is why I guess that shaft couplers are so common. You can get them new, or at any surplus place (surplussales.com)

Dan

[John Chapman]

Dan,

Good point. The small mis-match is o.k. if the knob is outside the chassis and the switch is at the front panel but as you describe if you run a staft/bearing type extension then the monvement as the shaft is turned will gight the switch/bearing mounts. The shaft couplings are an easy fix and another handy (but a bit pricey usually) place to get stuff like that is mcmaster.com.

Thanks!

John

[timoteus]

Thank you John and DrM for the very useful information.  I appreciate your help.