When refretting old fretboards the radius can be dodgy. Not exactly a set measure and it may vary over the fretboard. With a compound fretboard that's the rule! I love the Jaws2 press, but the cauls are firm and don't always follow the shape of the fretboard.

Today I came up with this tweak to a 16" radius brass caul. I made eight cuts almost all the way through the caul with a small metal saw to make nine somewhat movable parts (with the set screw on flat metal in the middle). To make it even more bendable I drilled a 3 mm hole in the end of the cut. To give the caul a chance to bend in the Jaws2 tool I put a shim of a soft but hard enough material in the bottom of the groove for the caul. I tried cork and it worked, but settled for raw rubber from the yoga mat I have on my bench. An old fretboard with 7.25" radius was used as an example.

The fret is pressed relly tight with normal force. The caul forms itself to the fretboard radius.

Here is the soft shim under the brass caul (cork and yoga mat). The set screw shall be loose and only as tight it needs to be to keep the caul in place, it has to be movable.

Will be using this from now on. I'll do the same for a 20" caul and that's probably all the radius cauls I will ever need for all the different radius variants :-)

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Made the slot in the Jaws2 1 mm deeper with a hack saw. Put 2,5 mm thick leather as shim instead of the rubber. Leather is harder and when testing it it worked very good indeed.

I just remembered Nate Clark made one He used to stop by here sometimes.

I can't take credit for making an adjustable caul. I have made lots of specific solid cauls as the need has come up.

I have considered the adjustable caul many times. I'm guessing maybe Hesh is referring to an idea from Walter wright or someone else in this thread.

The first time I ever saw the idea was 15+ years a go in the old Stew Mac trade secrets book.

Now that David Collins has done the math on a set with small and even increments, and they are available, an adjustable one no longer seams necessary.

I thought I posted some pic's here showing my method for making custom size cauls but I can't find it.

Here are some more.

One size in particular I find  useful, but not in Andy's set, (yet?) is a 1 meter radius. I made it for a couple of classical's I built a long time ago. Now I use it frequently on re-frets that have flat boardswith   rolled over edges. Rather that take the entire board down, or make frets that hook down at the ends, I make it a 1 meter radius. It's almost imperceptible but works great on many old Mando's that had funky flat boards.

Mayby this thread will work.

I also stole Walter's magnet idea to make swapping them out quicker as you go down the board. The set screw was a pain.

Both similar and different :-)

The magnet trick was nice!

I hear that Google is working on a self-adjusting, self-positioning caul but they can't get the software to work if it sees an Ov*tion....;)

Thanks David for weighing in.  Very cool innovations!!!!

On a related note, I noticed that Jescar offers their verison of the Jaws 1 fret press for significantly less than Stew Mac sells theirs for. It looks a little different, and they say their cauls press in with no set screw.

Has anyone tried it, and does it work as well? Will the stew Mac cauls fit in it?

The Jescar version comes with a paltry four cauls, but I've got two of each of the radii that Stew Mac offer, and soon I am going to pull the trigger on andy Birko's 24 piece Ultimate Caul Set that Hesh linked:

I already have a Jaws 1 and 2, but a second Jaws 1 would be handy to have in my shop, and if Jescar's unit will accept the Stew Mac size cauls, I think I'll get theirs instead and save a few bucks.

Another side note - What ever happened to Jaws 3? remember that one? It looked useful, but disappeared from the Stew Mac catalog before I ever got around to ordering one.

Chris, I find stew mac's jaws 1 a bit cro-Magnon. I don't use mine much. I prefer this DIY rig. nice, light, and controllable. little magnets let me click on a fret caul and a suitable neck back up block and go. It's all about magnets any more! Cheaper too! It's made from the shoe they sell for an arbor press.  Just remove a swivel from a small vice grip and use a strong tempered pin or bolt to hold the shoe on. The shims/washers have to be tight to nix any play.

I've had the same project on the back of my bench for a couple of years. Have you also used the StewMac Jaws 1, David Farmer? I've always thought my welding clamp seemed puny next to the ViseGrip they use. If by "Cro-Magnon" you mean capable of excessive force then I may reevaluate.

At $75, rather than $237, the Jescar press is certainly affordable. I always liked how Dan the Man used two for fret jobs, one for the ends and one for the entire frets.

Hats off to David Collins for yet another innovation. Birkonium was a great firm to partner with as Andy Birko does great work and is realible, speedy, and keeps in touch.

Hi Christopher, fyi, Hand Held Fret Press - Inserts not included$74.99 @ . I have stewmac cauls and they seem to fit.

The goal of a fully self-adjusting caul is one of those things where the closer I feel I'm getting, the further out of reach it slips. The biggest challenge seems to lie in achieving equal pressure along the length of the fret, while avoiding exerting any unwanted pressure outside the width of the neck. If boards didn't vary so much in width this would be much simpler, but designing a caul to clamp evenly across an upper flat classical fret, yet not crunch the ends over on the first fret of a P-Bass turns out to be a very tough challenge in design.

The biggest issue with the slotted cauls is even distribution of pressure. Of course with this design you would have to use a tighter radius caul than the board. This would mean however, that the pressure will inevitably be uneven. The center pressure would be controlled by pressure applied to the clamp, but the edges would only see whatever pressure is applied by the spring/flex in upper unkerfed portion of the caul. If cut too thin, this would leave tight frets (such as in compression fretting) unseated at the ends. Or if left too thick, it would crunch over the ends on a narrow neck with loose slots. Even with some sort of spring/foam/leather backing, you still don't end up with the ability to press evenly along the fret as controlled by pressure applied with the clamp.

I've tried several embodiments, including similar kerfed cauls, but yet to come up with a design that works well enough under a broad enough range of circumstances to consider the design successful. Here's the latest idea that failed and got tossed back in the drawer a year or so ago. Although it allows for even pressure distributed across six points along the fret, working from flat to 7" radius, and 1_1/2" to 2_3/8" width without over clamping outside the neck, the points are too spread out for thin or soft fret wire. I've considered adding a floating (secured only at one end) strip of spring steel to more evenly distribute the pressure, but got burnt out on this project and had to put it away for a while. Maybe I'll get back to it someday.


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