Bayou Jumper with Baby Bunnell Key

Jim Sheldon

Here's how I mounted the Bunnell model 6B ("Baby Key") on my Rev A
version of the Bayou Jumper in place of the normal built-in key
components that come with the kit. I was lucky enough to obtain 2 of
the Baby Bunnell keys at a reasonable price off eBay several months ago.
They appear to have gotten scarce again though some do show up from
time to time. The 6B was originally mounted in groups of 4 on some
Western Union telegraph test sets so the person doing the testing could
test 4 telegraph circuits nearly simultaneously and send/receive
messages on any of the 4 circuits without having to plug/unplug the key
to do so. As small as these keys are, they are remarkably easy to send
good CW with which attests to the superb quality that Bunnell
manufactured into them in the first place.

First, you have to remove the built-in key components including the
aluminum post used for the fixed contact on the main PC board. Put the
key strap mounting screws back in their holes to cover them for
aesthetic purposes. Temporarily disassemble the Bunnell key's rear
contact (ground) assembly. Be careful you don't lose any parts in the
process as they are not standard size/threads.

Position the key in place with the long insulated contact screw through
the big hole in the BJ's front panel and slightly ream out the contact
hole in the main PC board (not the front panel) ever so slightly so that the contact screw JUST fits. Next, while the key is sitting in the
proper position, mark the panel where the rear (ground) contact screw
needs to go and after removing the Bunnell key from it's position,
carefully drill a hole big enough to fit the ground screw at the place
you just marked. Now, reassemble the key and carefully shorten the rear
screw to protrude about a half inch below the panel when the key is in

Next, using one of the two nuts that are attached to each screw, along
with a large fiber, or plastic washer and a metal washer for support
loosely attach the front of the key to the large knob hole in the top
panel. As you are doing this, take the extra nut from the front screw
and thread it partway up that screw. Now, adding a #6 lockwasher to the
front screw above the main PC board, place it down through the hole
vacated by the aluminum spacer you removed from the main PC board
earlier. Now, tighten the front and rear nuts on the underside of the
front panel board to lock the key in position making sure it's aligned
square with the edge of the panel board to make it look good. Finally,
run the nut you threaded partway up the front screw down against the
lockwasher and top of the PC board. Using the last extra nut and a #6
flat washer on the underside of the PC board, secure the contact screw
to the bottom of the board. Using the nuts on both sides of the PC
board, adjust them so they are tight, make good contact and don't put a
bow in the PC board. You're done and have a nice little "real world"
key on your Bayou Jumper.

Good luck finding and mounting a Bunnell 6B key to the Bayou Jumper.

Jim Sheldon, W0EB

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