Top Deflection Gauge

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Top Deflection Gauge

Item # 5253
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Top Deflection Gauge

About This Item

Takes guesswork out of neck resets and bridge work! Accurately measures the distance a soundboard has lowered after the guitar is unstrung.

It's important to compensate for this distance when resetting a neck or when routing a bridge saddle slot. The gauge helps you avoid time-consuming trial-and-error.

Reset a neck without guesswork. The Top Deflection Gauge makes it easier to reset an unstrung acoustic guitar neck correctly. You can record a measurement at the bridge with the strings installed, and use a brace jack inside the guitar to restore the bridge to its exact original height when the strings are removed.

Perform bridge work more accurately. By using the gauge and a brace jack to simulate string tension, you can contour the bottom of a new bridge to more closely match the soundboard surface. When you rout the saddle slot, you'll know the bottom of the slot will be flat—that's important for good tone, and critical for undersaddle transducer pickups.

Keep your banjo sounding good: The gauge indicates banjo head deflection precisely—you can use it to record the head tension that makes your banjo sound its best.

Three holes in each end of the aluminum beam adapt the Top Deflection Gauge for a variety of soundboard widths, and a swiveling foot allows free-standing use. The dial indicator is super-accurate to .001", with adjustable zero point. The gauge measures 14" x 1" x 1/2" (355.6mm x 215.4mm x 12.7mm).

Instructions are included.


Product Instructions

Top Deflection Gauge Instructions

How to use the Top Deflection Gauge for neck resetting and saddle routing, banjo head tensioning, and assessing and adjusting neck relief.

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  • 5.00 average rating from 4 reviews
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Great for checking & setting the neck relief...and a whole bunch more

(Customer's Reviews)

I use this tool to check and set the neck relief, and a half-dozen other constant uses; I learned this from my Teacher, Frank Finocchio, who is not known by some, but THE best teacher of the Guitarmaking craft.


Accuracy Imperitive

(Customer's Reviews)

I purchased the Top Deflection Gauge to use in conjunction with the Neck Set Gauge already owned for a detailed record of existing condition of a 1937 Gibson L-00 which required a neck re-set. Along with the Erlewine Neck Jig and S/M Brace Jack accurate stress load conditions were simulated during the repair. Stew Mac tools are the backbone of my Luthier specific tool collection.


Precise measurement for neck reset

(Customer's Reviews)

I use this in conjunction with the neck set gauge and the neck jig work station for accurate neck resetting. Stew Mac tools are abundant in my shop.


High quality specialized tool

(Customer's Reviews)

This tool doesn't get a lot of use in my shop, but for critical undersaddle pickup installations, this is a must have tool.

StewMac PDF Catalog, page 18 See Top Deflection Gauge
on page 18 of our StewMac Catalog PDF

11.5MB File

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