This is a write-up I did a few months ago, then forgot to post it. I ran across it
today looking for a file and thought I should show it.
I have a 237 and was having some trouble with it lately. The tip kept getting plugged,
even though I twirled the tip cleaner often. I couldn't figure out why it kept plugging
in this particular manner.
The tip would build up a long piece of carbon. The carbon is in the shape of a cone, with
a hole through it similar in size to the pricker wire. The lantern would still run as this
"cone" grew, but it kept getting dimmer and dimmer, and finally the lantern would flame
and soot up.
I found that the problem was the pricker wire on the pricker rod did not go completely
through the gas tip. It only went through enough to barely stick out the top side of the
gas tip, and that allowed the carbon cone to build up over time.
Trying a new generator didn't help. The new one also had a slightly short pricker wire,
and it produced the same problem.
I checked an old 237 pricker I had, and found that the wire on it was about .050" longer
than the newer ones I have. That pricker worked well, since it came through the gas jet
far enough to push the carbon completely out and off the tip.
This write-up shows how I made a new pricker using only simple tools. I have a small
machine shop, but realize that not everyone here has the same equipment, so I did this
one with tools most everyone should have.
These are the tools I used. A good quality pair of cutting pliers. A good quality file,
and a good hammer. I say "good" because these things are made here, on the American
continent. You can buy whatever junk you like. I have a Chinese made hammer that is so
poorly made it cannot be used. I figure if they can't even make a good hammer, I am sure
not going to trust them to make something complicated, like pliers or a file.
One thing I used that is not shown in this picture is a medium hardness arkansas stone.
The material needed for the pricker is about 5" of 1/16" diameter brass tubing.
And a piece of wire for the pricker. You can get small diameter wire from a piano repair
place or a place that sells spring wire, like McMaster.
To make a pricker, you need a wire that is approximately .001" smaller than the actual gas
tip jet in your generator. For instance, if the gas tip is .008" diameter, you need
.007" spring wire, or music wire.
Also in the above pic, you can see I've bent one end of the brass tube to mimic the shape of
a factory pricker rod. Take your time and use the needle nose pliers to roll and shape it.
Use the file to remove any burrs and flat spots that are left, and try it in the eccentric
on your lantern to make sure it fits.
Once you have a good fit, cut the brass tube to the same length as your factory one.
I use a piece of wire that is about 1.5" long, so I can put a goodly length inside the brass
tube. Don't try to get the wire length exactly right at this point. Leave about 1/2 to 3/4"
sticking out of the brass tube so it's easy to work with. You can trim it later.
Use a ball pien hammer if you have one, and start tapping with a mind to close about 1/2" length
of the brass tube around the wire. Tap, then roll the tube between your fingers, then tap
again, over and over. You want to try to get the end peened around the wire somewhat evenly.
It won't be perfect, but give it a try. Don't just smash it flat on one side. It will be
unusable if you do that. Tap, roll, tap, roll, rinse and repeat. Eventually you will have
the wire captured in the tube, and the end of the tube will have a moderate taper to it.
Once you have the pricker rod and wire together, and the end closed to hold the wire,
it should look something like this.
Now, where you have cut off the wire, there will be a burr that will prevent it from entering
the orifice in the gas tip. Put your arkansas stone in something steady so it doesn't move
around and you can stone off the burrs on the wire.
Start at one end of the stone, and put your finger on the wire and press down.
Now, with your other hand, pull the pricker rod to the right while holding down on the wire.
You must also twirl the pricker rod as you pull it across the stone. At one end of the
stone, my fingers are holding the rod like this....
....and as I pull the rod to the right, I twist it between my fingers, so as the stone is
taking off the burrs, it is also making smooth edges where the wire was cut.
Do this four or five times, and the wire should be smooth on the end so it will go easily
into the orifice in the gas tip.
Finally, use the file to round off the shape of the peened end of the tube, so it will fit up
inside the hole in the threaded end of the gas tip. Same thing here as when dressing the
end of the wire. Push it against the cutting edge of the file while rotating the rod.
Note: Files only cut in one direction. They cut on the fore stroke. That is, the direction
that you would normally push on the handle. They do not cut on the backstroke.
That's about it for this thing. The new pricker with the longer wire fixed the problem
with my 237. You can make a new pricker for most any lantern you have with these few tools.
Thanks for looking.
Dean
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Steve , Keeper of the Light !!!
