Official Luthiers Forum!

Hesh recently spoke about leveling frets with precision, which is an attainable goal for a professional shop.

But basement builders like me don't have a professionally-equipped shop and aren't about to invest in one for what we do, but we do want to do the best job we can with the tools at our disposal.

Hesh mentioned his shop's sanding beams to be true to within .0005" per, roughly, a foot. Yikes! That's half a thousandth! I don't happen to own such a beam, but I do have some aluminum sanding t-bars and a aluminum carpenter's level. I can make an attempt to flatten these a bit (scary sharp) on my granite surface plate. Any idea if that would get me, the amateur luthier, 'into the game'?

And any other insights we home builders might be able to use?

Thanks!

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Peter Havriluk

It’s not that hard. My leveling beam is a foot long 1”x1” square steel tube from Home Depot. I flattened one side on Stickit sandpaper stuck to a sheet of 1/4” plate glass. Stickit paper on that side of the beam finishes it off. It’s truer than I can measure.

Aluminum moves a lot with temperature changes. I don’t know if that would cause you problems or not.

I still use the plate glass for larger surfaces like the beam or a plane base, but for scary sharp, I did move to a surfaced granite block. Handling the glass plate so much was worrying my toes. That was the “scary” in scary sharp.

I've been using the same aluminum level for 45 years. It is plenty flat. A super precise bar loses its precision after you attach a strip of sandpaper to it and start grinding away. A good fret level job is more about technique.

Getting the SM leveling beam was game changer for me and my fret work but there's no reason why can't true one up on glass as mentioned. the .005 is probably even overkill really. But it is nice for sure. BTW the leveling beam has many other purposes too.

There is an interesting article in American Luthiery #113 by Mark French on how to make flat beams by abrasive rubbing of 3 flat-ish surfaces against each other systematically. A mathematically flat plane is the only possible shape common to three flat surfaces.

https://www.search.luth.org/making-a-tr ... nding-bar/

Find a local machinist and make your own leveling beams it's easy to do.

Purchase 1 X 2 aluminum tube stock (it's rectangular but called tubes by the industry). Cut one length that spans the 1st through the 12th and a second length spanning the 12th through the last.

Borrow or access a certified surface plate (machinists have them, we have them too). Put self stick 3M paper 120 grit on the plate and mark up both narrow sides of the beams with red marks-a-lot market.

Sand, floss, burnish the beam on the plate with the 120 paper on it being sure to move around the plate and not stay in one spot. When the red is gone repeat. Now remove the paper from the plate and go 220 and repeat. Now your beams are accurate to what the plate is accurate to over their spans. I'm home now so I can't measure my beams or I would.

You only need two beams and they can be made very inexpensively and these are more accurate than any commercial offering. Many of the commercial offerings have some flex in them and that's an absolute deal killer. We will be bearing down at times so no flex permitted.

I have 120 on one side of my beams and 220 on the other and that gets me where I want to go. I have longer beams for basses and shorter beams for mandos.

A short beam is also useful to nix ski ramps on Fender style bolt on necks.

Regarding Durero's post yes that's a machinist technique and I believe how surface plates are maintained too with three of them. We find that none of this is necessary and our beams are accurate enough to achieve any possible action settings that we have ever been asked to do in the tens of thousands of guitars that we have repaired.

As far as maintaining the beams accuracy we used to check ours on the surface plates every year and then after ten years of no movement we stopped. They seem to hold their true for a very long time.

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Ann Arbor Guitars

Yep I use mine all of the time as mini surface plate to flatten nuts and saddle bottoms or put a bevel on a bridge pin so it does not catch the string ball.

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Ann Arbor Guitars

As long as you are making your own beams, you can also true up L and T shape extrusions for use as under-string levellers.

We don't. We don't use them and don't see any need for them. We also never, never, never spot level it's the entire fret plane for us or nothing at all. Strings see the entire fret plane so that's how we have learned to see it too.

I know people do use them Josh but they are not in our religion....

The only time we address say a single fret is when it's loose then we reseat, clamp and glue and Dave also invented a tool made from a spring loaded Awl that has a grove to ride on the crown of a fret. It's pressed into the fret usually the end that is loose and at some point the spring releases with a bang and the fret is power seated. We then glue. If it won't stay down we clamp and glue.

You're right anything can be trued up on a surface plate and the hope is that it has zero flex so it stays that way.

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Ann Arbor Guitars

I don’t do full fret levels with Understring beams. I do use a short understring beam, only occasionally and in particular circumstances.

A scenario where I might use it is where:

- The instrument already has a perfect or very good fret plane except for slight ski-ramp in the upper frets and levelling the whole board would mean unnecessary removal of height from frets 1 - 12 and
- The instrument is mostly well setup and not requiring much adjustment and
- Client is price-sensitive

In this scenario I can use the short understring beam before removing the old incoming strings to nix just enough of the ski ramp that the axe plays well at the desired target action. Then remove strings, quickly recrown frets 18-21, restring and setup and get customer out the door for the price of a setup within the amount of time a setup nominally takes. Using the understring beam to deal with the ski ramp means I can test as I go and remove the minimum necessary to play clean without spending any more time than necessary, so customer goes away happy and I’m able to still bill at my standard rates.

Check out what Music Nomad has to offer. There beams a bit more cost effective than Stewmac especially if you qualify for discount.

https://www.musicnomadcare.com

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Get a quality fret rocker first, in the 10 to 15 USD mark. Cheap ones are not straight. A bad rocker and a long beam are a recipe for disaster when you start.

Start with a 6 inch beam. Flatten it on a known flat surface like a 3/4 inch granite kichen top and use 300 grid. Begin on used guitars, not new builds and make the fretboard perfect. If the neck is good you can get an action of 1.2 mm and lower this way. Work slowly, with method, don't grind of much.

A fret rocker is not for leveling frets it's a quick check and should never be used for anything other than finding high frets. Leveling should always be done addressing the entire fret plane at once.

6" is too short and only used professionally for the 12th through the last and inducing fall away. At a minimum you need a beam that spans the 1st though the 12th and a short one for the 12th though the last.

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Ann Arbor Guitars

Alwin your information is incorrect. Are you a professional who works in the trade? Please read what I wrote earlier in this thread.

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Ann Arbor Guitars

So I offer again you can make your own beams, we do out of 1 X 2 aluminum tube stock cutting to length and safing the edges on the ends and sides. Some self stick 120 and 220 and a visit to a machine shop offering to buy lunch for a couple hours use of a calibrated surface plate (we have our own) and you can produce beams accurate over their spans in flatness to 0.0005" quite easily.

Use magic marker, we like red Marks-a-lot as "bluing" to check progress. When you remove all the red in one short session the beam is level.

Additionally I used to be tasked with doing this same set-up annually to check if the beams are changing over time and with use. After checking for about 6 years annually and seeing no movement we don't check anymore it was not productive they stay pretty flat.

Be sure to flip the beams and turn them around periodically to reduce errors from technique and/or the plate.

This produces a set of beams that may only cost $10 for two of them if you find a machine shop that appreciates you are guitar makers or repair folks.

Murray McCloud who we have not heard from for a while and I hope he's OK is an OLFer who offered these beams made how we do for sale at reasonable prices.

With this said our method of producing beams is way cheaper than the StewMac beam which is excellent by the way and has more heft which can be a good thing than ours.

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Ann Arbor Guitars