B747-400 APU rotary switch

[thomas747400]

Hi guys,

I have been unsuccessfully searching for a B747-400 style 3 position APU switch. The problem is getting a switch that spring return from right to center.


Also, I was wondering if authentic Boeing rotaries have a rotation angle of 30 degrees like the rotaries you buy in the electronics stores.

Finally, where is the best place to buy Boeing style knobs, I found that they can be rather expensive and I need about 20 of them. To me, they all look the same but are there big quality differences with them? Are they usually designed for a round or D shaft, 6mm or 1/4".

Kind regards

Thomas

[gregh]

Hi Thomas,
I took and ordinary 3 position switch, say from Altronics and bogged in the 3rd position indent on the inside. With the switch mounted underneath the panel, I drill a hole in the shaft for a small stiff spring at R/A to the shaft. The spring hits a "stop" screw mounted in the backing plate to return the switch to the "on" position.
I would recommend the knobs from FDS and if you buy the unpainted ones the price is quite reasonable.

Regards
Greg

[thomas747400]

Hi Greg,

Thanks for the reply! I think I get the concept... any chance of posting a picture? I am a frequent visitor of Altronics as well... this would have to be one of the best electronics store I know.

Regards

Thomas

[gregh]

APu Switch.jpg

Hi Thomas,\Hope the pic helps.

Regards
Greg