I have been meaning to do this post for a while, so here it finally is. How to add copper braid to a tail (or driver) spring.
This mod reduces the resistance of the spring significantly, especially steel springs. This may not make a big improvement on a brass spring, unless you plan to push some real serious current. J)
OK, Here's what you need:
- Tailcap with a spring in it (driver springs need love and attention too).
- Copper braid, the type with no flux is best (1.5mm to 2.0mm, wider might be difficult to work with)
- Needle-nose pliers
- Soldering iron (not shown)
- Helping Hands (not shown, optional, but highly recommended)
First, open up the tailcap using the needle-nose pliers. Insert the tips into the ring holes and turn counter-clockwise (if you have a press-fit tailcap, usually they need to be pushed out from the switch boot side).
Here's the victim patient:
Prepare the braid by bending the end a little:
Note, if the spring is only soldered in one spot, it is best to solder it on the other side as well. This will prevent the spring from falling off when you melt one of the solder spots.
Position the braid on the bottom of the spring just over one of the solder blobs.
Hit the solder blob with the iron and fresh solder. As soon as the solder spreads to the braid, remove the heat. You want to prevent the solder from 'climbing' too far up the braid.
Now that the bottom is secure, snip off the top of the braid with enough excess to allow the braid to wrap around the spring. Leave a little slack inside the spring.
Now we pre-tin the top of the spring so the bonding occurs quicker when we solder the braid onto it. I tin where the spring top is lowest, so the braid doesn't stand up higher than the spring. This prevents a potential 'hotspot' where all the current flows through a tiny contact point.
Wrap the braid around the spring end:
Solder the braid on with heat and a small amount of fresh solder.
Trim the end as necessary to reapply the spring cap
Replace spring cap, ensuring it slides down all the way. Some prefer to leave the cap out as it adds another contact point, but in my testing it is negligible. Plus, it looks better.
Reassemble the tailcap and you are done! Doing the driver spring is virtually the same. Really short springs may be a little trickier, but can be done.
NANJG 105C springs do not need copper added, but I recommend replacing them with real springs (mounted upside-down) to add some shock absorption. It prevents inadvertent mode changes.
I hope this has been helpful. Happy Modding! searchID8936