May 04 '07 - 553 W, 3 I - Vote Good + 6 :: Bad - 5 Nuts 'n' Bolts:: On the Other (4th) Hand
Published May 4, 2007 by C.I.C.L.E.
Contributed by Harv
Photo By harv
A tool for every purpose is what mechanics (and manufacturers) like to believe. But sometimes they can over do it. There are several versions of "fourth hand" bicycle control cable tensioners that allow the mechanic to eliminate slack in a brake or shift cable when anchor bolts are to be tightened, brakes adjusted, or components positioned. 
I have found these devices clumsy and awkward to use.
Cables must be positioned and squeezed in the tool at a cam lock pinch-point, the handles are then squeezed to pull the cable to the proper tension, and then a locking detent is maneuvered into position. To free up your hand, the whole heavy mess must dangle and may bang against other parts.
Of course, you knew I would have a better way, didn't you? At least, in my opinion it is a better way. My method may require two simple tools instead of one clunky, complex, and expensive tool. Basically, I suggest you pull on the cable end to take up the slack and use a hemostat to clamp it in place. Hemostats are surgical instruments used to pinch off a blood vessel. Or... they can be used as a fancy roach clip. But we are not here to discuss this kind of stuff. There are other ways to clamp a cable into position, such as a "vice grip" locking slim nosed pliers, a small c-clamp, or a heavy duty spring clamp. But the hemostat has the advantages of lightweight, one-handed operation, no adjustment necessary, and quick action and release.
If you just want to take the slack out of the cable up to, but not including, the brake arm spring or derailleur return spring, you should be able to pull the cable by hand. If not, you have issues with friction in the lever or cable housing. Check for corrosion or crimps in the cable. If the return spring adds too much force to overcome by hand, you can use a pair of pliers to tension the cable. Even so, my method is simpler and more direct than the commercially available tool. Or, you can close the brake arms against their return spring with a third hand tool, discussed in a previous tech tip.
When all adjustments and tightening of anchor bolts are done, just release and remove the hemostat and the brake or shift mechanism should be ready to go. Hemostats are available on EBay for only two or three dollars each, including shipping. Harbor Freight Tools also has them, although they seem to have only the 12 inch ones, which would be overkill. A five or six inch hemostat would be about right. They are available with straight or curved tips, the curved tip is more suitable for bicycle work in that it would hang down out of the way while in use.
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Ah, yes, the multi-purpose “roach clip”—pure genius, as always!
One of the other benefits of using a hemostat is it doesn’t crush or damage the cable in any way (can’t provide enough clamping force to damage)...it’s probably safer to use, and certainly less awkward, than a traditional fourth-hand tool.
Ghost Rider (Email) - May 05 '07 - 06:37
Interesting, perhaps we will try this at Bikerowave.Alex Thompson (Email) (URL) - May 08 '07 - 16:54
I’ve never had an issue using a “4th-hand” tool. I find with any tool, and teaching people how to use tools, its about using them properly, and sometimes with a little finess. I can tighten/adjust a cable no more than a 4th-hand and the appropriate wrench quite easily.Dobie - May 18 '07 - 17:52