Imagine working a dock, weedline, or other structure with a crankbait. There is always that one spot you can't seem to get underneath. You cast and the crankbait comes straight back to you. You'd like to cast your crank under the dock, but you may not be able to. So you reach into your tacklebox and grab a crankbait that you've fine tuned to swim a little different.
You can make the crank swim along or under a dock, along a weedline, or other structure by making one of two modifications. If you want the temporary modification, use a pair of needle nose pliers and bend the eye or wire you tie to on the crank in the direction opposite the side you want it to swim. Want it to swim more to the left? Bend it to the right. Make slight adjustments incrementally until you have what you need.
If, however, you'd like to make a more permanent modification so you've got one crank that favors its left and one that favors its right, you can shave down the lip. Use whatever you feel confident with to file it down. A dremel is ideal. File the edge off little by little until you get the desired result. The results really do vary depending on the brand from what I've read. You'll likely ruin a few cranks, so try it on something cheap or beat up and then try it on a good one when you figure things out. The way I see it, there are two ways of going about this. I was able to find contradicting instructions and both were rather vague, so I'm left sorting it out on my own. If you shaved the opposite side, you shaved off a vertical edge of the lip so the resistance on the unchanged side causes the crankbait to dig and pull to that side. If you shave the lip on the same side you want it to go, you must have shaved it across the top at a slight downward angle so it one side is slanted down at a sharper angle than the other.
I would appreciate some clarification from anyone who modifies crankbaits. It sounds like turning the line eye is the recommended way to go about it and shaving the lip down is not so popular.BPS makes eyelet tuning keys and I believe Rapala has pliers with tips that are designed for bending eyelets.
If you would rather make your crankbait swim a little deeper, you can use the dremel tool to shave some of the plastic off the bottom edge of the lip. Don't take off too much or you might weaken the plastic causing it to break.2 You might consider this sort of mod if your crankbait of choice doesn't seem to dive to its advertised depth.
In Fishermen has published a tip related to tuning crankbaits and also has an image illustrating how to adjust the eyelet. Whenever they archive it with a more permanent link, I'll post it here. Until then, go to their site and look for the weekly tip section.
1. In Fisherman. "In Fisherman Weekly Tip - How To Tune A Crankbait"< http://www.in-fisherman.com/reference/weekly_tip/current_tip/index.html > 2008. 10 April, 2008.
2. Jordon, Kelly. "Here's How To...File the bill." Bassmaster Magazine. September/October 2008, Volume 41 No. 9: pp18.
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