Crawls Backward (When Alarmed)

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DIY Guitar Fret Wire Bender Mk II: New and Improved?

While I'm waiting for the parts for the Jazzmaster to arrive, I found some other trouble to get into.

You may recall my previous attempt at a fret wire bender.  It worked ok, but I wasn't happy with the alignment of the rollers, and the crank didn't fit the main roller shaft well at all.

So I decided to make the Crawfish Fret Bender Mk II.

I followed the plans from LMI much closer this time, starting with a 1/4 inch thick aluminum plate.  Cut it into a 4.5 x 4.5 inch square.

Then file and sand the corners a bit to make it look all nice and professional looking.  As if.

I also sanded all the edges so they weren't sharp.

Disassembled the old fret bender.  The wood base will probably end up as a caul or something.  By the way, wood works fine for one of these I think; I just wanted to try aluminum since that's what the plans call for.  It is much stiffer in torsion, for what that's worth.

I got the exact patio door rollers and crank the plans called for.  Turns out the rollers I had were exactly the same.  Whatever.

Over to the drill press to drill some holes.  Lookit that crazy swarf that comes up from the aluminum.  Don't put your hand in there.  It's pretty sharp.

Back to the vise.  There is an adjustment slot that I fabricated by drilling a few holes close together.  Then I filed between the holes and used the Dremel grinder attachment until it disintegrated.

I know Sven of Argapa has (I think) a Proxxon tool - probably better than the Dremel.  The Dremel is ok, but most of the attachments last for one use and that's it.

Here's the plate all drilled and ready to assemble.  The slot looks bad.  But it's functional.

You can pretty much emulate this easily.  The top hole is 5/16, and the right hole and slot are 1/4 inch.  The center hole for the top is about 1/2 an inch down.  I think the two outside holes are 1 5/16 in from the edge.

The measurements probably aren't too critical - if you have the hardware you can lay it out and eyeball it.  Or you can buy the plans!  (What a concept).

Here's a sort of cross-section view of one of the two lower roller assemblies.  I used a 1/4 inch x 1 inch hex bolt.  Put the roller on, then a washer.  Then slip that through the hole.

On the other side, put on a washer, a lock washer and a nut.

Hopefully this helps to visualize how it works.  You tighten down the nut, but the roller can spin on the shaft of the bolt.

View looking down on the top.

The top roller is a sandwich (mmmm...) of two 1 1/2 inch round 5/16 washers around a 1 1/4 washer.  A 5/16 bolt goes though this 'pulley.'  Put a thin (the key is THIN) nut on the bolt and snug the pulley up.

Then slip it through the hole and put a window crank on the other side.  This is another key bit - the crank should have a fairly tight fit on the bolt.  My first version had a lot of slop and the crank wouldn't stay on!

Here's the fret bender in action.  Works very well.  I also decided to go with hex head bolts and it looks nicer I think.

Feed the fret wire in from the left and crank it through.  The slot lets you adjust for the radius you want.  If you need flat for an ukulele or classical guitar, the slot will need to have a good bit of adjustment (I'm going to extend mine more).

I have 3 (I think) guitars to refret.  But first, I have this.  It's my prewar Martin tenor ukulele.  I had levelled the frets, but I'm biting the bullet and refretting it.  I'm also going to do something with those unbelievable divots.

Good luck to me.


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