Contact problem with 4x123 in a 2C

Need a little help making 4x123 work in a 2C. I know about removing the anodizing in the back of the tailcap and making a negative contact point (i.e. steel wool, aluminum foil or very small compression spring.

Here is the problem: The 4x123 keeps the tailcap from screwing down completely. This creates an incomplete contact point between the body and tailcap. With 3x123 the tailcap must be tightened down to complete the circuit / have the light come on.

What is the trick to creating the body-to-tailcap contact point with 4x123? I didn't see any metal washers at Home Depot that would work.

I am using Battery Station 123's.

Thanks for the help.

Neal

I just finished playing with the parts you are tring to fit together.

There's not enough length in a 2c even if you machined the tail cap for all the internal space possible.

The easiest solution two minutes of thought provided is to assemble your parts, twist the tail cap down to contact, back the cap off 1/2 turn, wrap bare wire (gauge of your choice) in the space between the contact surfaces of the cap & body, then snug down the tail cap.

It's a bit of a junkyard fix untill you can locate a correct size of pipe to cut a piece from or have a short ring machnined to fill the space cleanly.

Theepdinker

I believe that if you
remove the rubber boot over the switch,
loosen the switch and move it forward a little bit, you can make the 4x123 work.

Don't stop there, not quite enough room without denting the bases of all the batteries. /ubbthreads/images/graemlins/rolleye11.gif

Remove the retaining clip that's in front of the switch.
Add a small wad of aluminum foil in the tail cap.
DON'T USE STEEL WOOL IT BURNS.
Install your batteries.
Slide the switch in on top of the battery stack.
Push the switch assembly down firmly(bulb is removed right).
While pressing on the switch, tighten the allen screw.
Reinstall switch boot.

You should be good to go.
What bulb are you planning to run?
I tried a kpr118.
It looks like my wife's kpr112 on 3-123's.


Theepdinker

Thanks for the ideas.

I tried Litho's method first. It did not move the switch up enough to allow contact.

Theepdinker, I tried your junk yard fix with a piece of metal wire. It worked but didn't look good because I did it rather quickly just to test. I may try your other idea - removing the retaining clip.

Re the bulb, I am getting some WA1318 later this month from the large group buy and I haven't decided if I'm am going to use 4x123 or 4.5x123. I thought it would be a nice small package if I like the beam with 4x123 in a 2C. While I am patiently waiting for the bulbs, my test today was with a bi-pin bulb I picked up at Radio Shack (I don't recall the bulb number but it was 12v and less than 2 amps for $1.99). The output was less than the KPR112 / 3x123 and was yellow. Put it back to the KPR112 / 3x123 config and will wait for the 1318 bulb to try again.

Neal