StewMac Fretbar Understring Leveler

StewMac Fretbar Understring Leveler

StewMac Fretbar Understring Leveler 4.5" Length

4.5" Length

Item # 4641
In stock, ready to ship!


StewMac Fretbar Understring Leveler 9" Length

9" Length

Item # 4642
In stock, ready to ship!


StewMac Fretbar Understring Leveler 18" Length

18" Length

Item # 4643
In stock, ready to ship!


StewMac Fretbar Understring Leveler String Jack

String Jack

Item # 4659
In stock, ready to ship!


StewMac Fretbar Understring Leveler, 4.5" Length with Stikit Set

4.5" Length with Stikit Set

Item # 2344
In stock, ready to ship!


StewMac Fretbar Understring Leveler, 9" Length with Stikit Set

9" Length with Stikit Set

Item # 2345
In stock, ready to ship!


StewMac Fretbar Understring Leveler, 18" Length with Stikit Set

18" Length with Stikit Set

Item # 2346
In stock, ready to ship!


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StewMac Fretbar Understring Leveler

About This Item

How do you level the frets at the right tension?
One of the most challenging things to get right with any setup or fret work is knowing the frets will be level under actual string tension and playing conditions. Now we've made it easy.

Our solution for this was the invention of the Erlewine Neck Jig—the industry standard when it comes to simulating string tension to get the most accurate fretwork possible. But let's face it, sometimes jobs are too small to strap them into the Neck Jig, or you need to work outside your shop where the neck jig isn't practical. We knew there had to be a better answer.

Now, you can level your frets...with the strings ON!
Matt Brewster from 30th Street Guitars brought us this amazingly simple (but effective) idea for getting perfect fret dresses with the strings still on the guitar. This great idea became the StewMac Fretbar Understring Leveler, or simply the Fretbar. This revolutionary new tool lets you level your frets under full tension without removing the strings. It's designed to work with our 1" wide 3M Stikit Gold Abrasives for ultra-fast set up and leveling.

Fret work without guesswork
With the Fretbar you'll level the frets with the exact tension the neck has when played. This is because the Fretbar fits UNDER and BETWEEN the strings, with the guitar tuned to pitch. The precision-ground surface is just 5/64" thick, allowing you to glide under the strings when leveling.

Because the neck is under tension, you'll clearly see every hump, twist, high or low spot. With the Fretbar you can level the frets without worry or any "surprises" that pop up after the job.

There is a Fretbar for every leveling job:

4.5" length ideal for spot leveling problematic frets all over the neck. It's also perfect for creating fallaway on acoustic guitars.

9" length is designed for smaller necks like ukuleles and mandolins. It also works for leveling full scale necks and spot leveling.

18" length makes it easy to level an entire neck. You'll quickly and evenly level most of the frets at the same time, without the added danger of running into the nut, saddle, or hardware.

We also include the String Jack to use with the Fretbar. Put the jack in front of the nut to raise the strings without changing the tension on the neck. We've got replacement String Jacks as well.

Works with the strings off too
This is also a great all around fret leveling tool. Used with the strings on or off, the precision-ground surface works quickly and accurately to get frets level. If you're just getting started or have a ton of experience, the Fretbar is a great option for any fret work.

    Built for a lifetime of use
  • Made of durable extruded 6061 aluminum
  • Guaranteed accuracy of ±0.0015" per foot
  • Designed to work with our custom 1" wide 3M Stikit Gold Abrasives
  • Works with the strings on or off

Your fastest and most profitable leveling ever
Because you don't need to remove or replace the strings, you'll save time on every leveling job. And with our 1" wide 3M Stikit Gold Abrasives—already cut to the perfect width—you're ready to level in an instant. No more wasted strings or sandpaper!

Save with the set: Fretbar and Stikit Set
Stikit Abrasives cut like a file, last longer than regular sandpaper, and are sized to stick right to the 1" width of each Fretbar. These are the same professional sandpapers we use to quickly and cleanly level frets, and to remove the scratches before you recrown and polish.

Each set includes one Fretbar and four 15-yard rolls of Stikit, one of each grit: 320, 400, 600 and 800-grits. More grits are available separately.

Each Fretbar is 3/4" (19mm) wide x 1-15/32" (37mm) tall extruded aluminum, and available in three lengths: 4.5" (114mm), 9" (228mm), and 18" (457mm).

Works on stainless frets, too!
All of our tools are suitable for use on stainless-steel fretwire, with the exception of our Fret Tang Nippers. Modern stainless-steel fretwire is known to be harder than the traditional nickel-silver blends, but our own shop experience indicates the wire does not cause premature wear of files or sandpapers.

WARNING: Cancer and Reproductive Harm -

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Work under string tension for those quick level crown & set up


Verified Buyer

I run two of the Aluminum Fretting Jigs and working under string tension is a must for me. This tool is great for that light leveling prior to a pro set up. I keep mine with 400 girt 3M gold paper and the eight of the tool helps lightly kiss the frets or you can press more if needed. If the guitar needs more attention it’s going in the jig for heavy lifting.


These rule!


Verified Buyer

Having used the under string fret leveling method for 10 years or so when Matt showed me his prototypes for these I could tell they would be winners. I have replaced all my fret leveling tools with these at this point and use nothing else for under string, but more importantly without string fret leveling. They are amazing for entire levels, upper fret board humps, etc. The ability to play the guitar while you are doing the work cannot be stressed enough for removing the minimal amount of fret height. I have also had amazing results using them for fretless bass fingerboard inconsistencies. Level and test. Just so simple an efficient. I love that Matt totally went outside the box on these tools! Love them!