Official Luthiers Forum!

I've owned a Jaws II fret press for years, as well as the full Birkonium caul set, but I've never been able to get it working well enough to replace hammering.

I can press a fret 80% of the way to fully seated with no problem, but that last few thousands to get it really well seated just aren't happening, no matter what combo of cauls and how much pressure I'm using. The amount of futzing required also seems excessive, and I always have to finish off with a few hammer blows. At the moment it's taking more than twice as long as a hammer-only fret job, with no discernible advantage that I can see. Since there's so many very well-regarded luthiers who use it, I'm operating on the assumption that my struggles are down to user error, equipment malfunction, or both. So I'm asking for help - if someone with some Jaws II experience could help me figure out where I'm going wrong, I'd really appreciate it.

Prep process:
1. Prep board - I sand to achieve dead straight FB surface with an accurate, consistent radius (I most often use 16")
2. Prep slots - check slot depth is appropriate, saw deeper if needed, bevel top of slots with triangle file.
3. Test slots - I have a piece of fret wire with the barbs lightly filed off which I use to test each slot. I aim to get the slots in a state where a light tap on the barbless fretwire is enough to seat it fully.

While I'm not achieving great results, I've arrived at the following process, which gets me the closest and requires the least hammering to finish the job:

1. Lightly tap in both fret ends with a hammer to hold fret in place and upright.
2. Start pressing with a tighter radius caul (say, 14.75") to get the ends well seated. (Have to walk clamp back and forth and press from both sides)
3. Press middle of fret down with a slightly flatter caul than the board (say, 17.5") to seat the middle (Have to walk clamp back and forth and press from both sides)
4. In theory if all the above goes well, this is where I would clamp the fret down with a caul that matches the board (16") and wick CA under the fret for insurance. But it never does, so this is where I use a hammer to fully seat the fret.

I notice when applying pressure that my Jaws only really squeezes down tightly at the end of the fret closest to the clamp bar. So I have to squeeze a bit, back off the pressure, walk the caul along the fret slightly, squeeze again, remove the press, flip 180 and reapply it with the bar of the clamp on the other side of the fretboard to get *that* end down, back off the pressure, walk it along, squeeze more etc. Here's a pic kinda showing the issue:



After all that futzing, at best I get to the point where I can still slide a .009 feeler gauge between the fret crown and the fingerboard surface. At this point, I am applying as much pressure as I can with the clamp and the fret won't budge further, it just stops like that, part-way to seated, with a the .009 gap visible under the crown. If I remove Jaws and whack it with a hammer it sits down perfectly.

Where am I going wrong? Does my process sound OK? Could my Jaws II clamp itself be faulty? Maybe there's too much flex in the bar, or it's slipping, or something. Maybe I need to prep the slots differently?

I don't know if it's the pic, but the padding in your caul looks thicker than what I have on the caul's that came with the Jaws. Is your caul the one that came with the tool? Could the neck be squirming away from the brass caul and getting wonky in the clamping caul?

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

One other thing that comes to mind... what is the fret slot width and the thickness of the fret tang? Would the fret barber help?

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

The neck is resting the padded felt-lined caul that Stewmac supplied with Jaws II. Good point, maybe I need a caul with less give in it.




Slot width is .023". Fretwire I'm using is from Stewmac and supposedly sized for this slot. It does indeed fit perfectly when installed via hammer. Maybe the barber could help... does pressing normally need a wider slot compared to hammering?

The fret barber lets you take some off the barb of the tang - https://www.stewmac.com/luthier-tools-a ... arber.html

What is the part number for the fret wire you’re using with your 0.023 slots?


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

It's 0148-LB

When I measure the size of the tang in between the barbs with verniers I get between .0235 - .0255

Here's an exaggerated drawing to give you an idea of what's probably going on and how to fix it. Since the real caul is fairly circular, you probably don't need to tilt it. Simply scoot it toward the outer end of the jaw a little bit. Or scooting the fret caul closer to the bar should have the same effect.

SM fretwire comes flat. Are you putting a radius on it to closer match the 16” radius of the board?

What I can say is that I also use the Jaws, I use the fret barber to take the barbs down before installing and I radius the wire in advance. They typically sit down without having to tighten the clamp full stop.

Hope some of that helps.

Brad


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

Thanks Dennis, that makes sense.

Yes, I do radius the wire. I'll try the barber, thanks Brad.

Do you press with just a single brass caul, that matches the FB radius?

Good point, I have the same set of cauls from Andy that you have. I use the next one down. Is it 14.75”? Anyway, the one next to 16”.


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

I have used the vice grip jaws for 14 years. I don’t think you can ever assume the caul will match the fretboard radius exactly. If you level the board on the guitar with a long bar and sandpaper and fret as a last step the leveling is going to probably induce some variability in radius. Especially if you level in line with the string runs.

My sequence is fill the slot with hide glue, seat the ends of an over radiused piece of fretwire with the dead blow hammer, clamp with a caul a little tighter than the radius (14” for a 16” board) and move the caul a little back and forth to insure even pressure and then do the final seating with the hammer after trimming the ends.

I fret with the neck on so after 10 I hammer them in. I could never get the clamp designed by StewMac to work to my satisfaction but I think Hesh et.al. have done so.

This approach has worked well for me.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

Thanks for the details, Terence.

Not able to help, but I've experienced the same & have also gone back to tapping them in with a small dead blow hammer. I took Hesh & David's class & they firmly endorse the Jaws (they also do outstanding work) but I was never able to get it to work better than tapping for me.

Besides not being able to perfectly seat the fret, I hated how hard I had to crank the stupid little round handle. At 53, I've hurt my hands enough to know what's not a good idea.

I suspect the problem is that the fretboard contour doesn't perfectly match the caul and the frame of the clamp is too flimsy and distorts as pressure is applied. Maybe a large hydraulic setup with a massive rigid frame would do the trick.

Good luck.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Two things. You don't want the slot too wide when pressing frets. You said you open the slot so you can tap in the fret with a couple of light blows. I think a tighter slot is better to hold the fretwire once it is pressed. A wide slot may allow the fret to pop up in one spot as you are pressing another.

Two; the fit of the caul to the fretboard radius is really critical. Getting a perfect match is difficult and it may change slightly as you go up the fretboard. This is what works for me. I chose a caul with a slightly smaller radius than the fretboard so that the ends of the fret get pressed flat, leaving a slight gap in the middle. I then lift the caul and slip a small piece of cardboard under the caul at the middle. Then I finish pressing the fret. The cardboard that I use is a piece about 1/2" wide and a couple of inches long, cut from the boxes that over-the-counter medications come in. The cardboard is about .030" thick and is coated on the outside. This process goes quickly and presses the fret fully.

Another Ann Arbor grad here. I use the fret press and Andy Birko's caul set. I don't have to use a hammer or a huge amount of force on the clamp screw. As Barry said the fit of the caul to the fretboard is crucial and I check that every fret although I normally only use 3 or 4 different cauls as I work up the neck. I do it little differently (don't we all) and I use the caul that is an exact fit to the fretboard. I use hide glue to lube the fret, my slots are standard width and I don't do anything special to the frets other than trim the ends to fit. I use a #5 Exacto blade ground into a hook shape to clean out every fret slot before I get started and I also check the fret slot depth with a de-barbed fret. I use the standard StewMac neck caul with the felt pad so I don't think that is an issue.

One thing I have done to my Jaw's clamp is to take a file and clean up the threads then lube them - makes it work a bunch easier. I also got the inside threads as much as I could reach. Basically just break all the sharp corners.

_________________
Steve Smith
"Music is what feelings sound like"

That cardboard shim is a good idea. Thanks!

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

The side benefit of the cardboard shim is that the fit of the caul does not have to be perfect. Works well with the Stew-Mac caul set which only has a few caul sizes.

Quick question:

What are all of you cutting your slots with & what wire are you using?

I use the Stewmac circular blade. On my last build I tried to use Evo nickel silver but changed to Stewmac because the Evo was too tight - it was also an African Blackwood fingerboard which is super hard.

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

I’ve been using a hard maple caul in a drill press. I cut the caul to match my fingerboard radius. Every couple of years, I have to redress the maple caul. The wood crushes and conforms to the fret and generally does a pretty good job. Every now and then, I get a problem fret that requires a tap, but not often. I also wet the fret slot to make the fingerboard a bit more pliable to receive the barbed fret, and squirt a line of Elmer’s glue after that just so there’s a bit of glue to encourage the fret to stay over the years. It’s simple and it works.

I use the Jescar 43080 wire and a 0.023 slot. The Jescar wire comes coiled so I don’t have to worry about the radius. I use the fret barber to take it down to 0.026. I fill the slot with HHG. They press in and are usually seated way before I’ve tightened the clamp fully.

I’ve used the same process on everything I’ve built so far (12 whole instruments!!! ) other than I used CA initially.


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

Well, I open it up so a test fret with all the barbs filed off taps in with a couple of light blows. The actual frets, and their barbs are a tighter fit.




Good tip, I’ll give that one a shot, thanks Barry.

Thanks Kevin, good to know I’m not alone in struggles here!

Thanks Steve. I’ll do some remediation on the clamp, and try squirting a bit of hide in too.

It’s interesting that so many of you are succeeding with slightly differing pressing techniques, makes me think there’s something big and obvious I’m missing in my attempts.

When I cut slots I use an 0.024" blade and use regular EVO (Jescar 43080, 0.020" tang) on my new builds. For standard refrets I use nickel silver fret wire (Jescar 45086, 0.020" tang) unless the client asks for something else. I do more refrets than new stuff but.

_________________
Steve Smith
"Music is what feelings sound like"