Servo wires are small — 24 gauge is typical — and the pins that crimp to their ends are fragile.

So when I’m confronted with a servo lead that’s too long — this happens often — I usually ignore the problem and wad the extra wire at one end or the other.

If the lead is too short, I use a servo extension: convenient, but it adds weight and it’s never exactly the right length.

I’ve tried shortening the wires and crimping on new connectors, and I’ve botched the job badly.

How many ways can you waste a servo pin?

• Crimp it onto the insulated part of the wire, rather than the conductors
• Squish the servo pin, missing the wire altogether
• Deform the servo pin, so you can never properly insert it into the shell that holds the pins

Blame the crimping tool. That’s my first impulse. Buy a new crimping tool.

Crimping Science. But when I fail with the new tool I realize that there’s a science to crimpery and that I’m stuck in the Dark Ages with two crimping tools but no light.

In the absence of a better alternative, I sometimes splice a servo lead to shorten it. If I have enough length to work with, splicing is easy, albeit less elegant. I minimize the thickness of the splice by cutting the wires at 3/8-inch intervals and insulate with a single piece of heat-shrink tubing. By cutting the wires at an offset, I insure that the wires won’t short.

My friend Bruce Crawford once explained proper crimping technique to me but at the moment I had nothing to crimp, so most of his insights quickly floated out of my head.

Seeing Big. I do remember that he advised using a magnifier — he likes the kind you wear on your head — so you can clearly see the pin, the wire and the slot in the crimping tool. He also pointed out that the pin has two clasping sections: one is designed to hug the insulation while the other clings to the wire.

The other day, Bruce sent me a link to a Connectors PDF file created by Hansen Hobbies that seems to answer every question about the care and feeding of servo leads, housings and wires.

An Honest Guide. It’s clearly written, amply illustrated and, as author Chris Hansen writes, “an honest tutorial rather than an advertisement for our products.”

One of his coolest tips is how to strip all three strands of servo wire simultaneously, and he offers much more useful and time-saving information.

I read it and liked it so much that I saved it to my hard disk so I can consult it the next time I need to grapple with an untamed servo lead.

Tags: Radio Control, Tools.

This entry was posted on Thursday, September 18th, 2008 at 7:23 am and is filed under Baylands. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.