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Steel Strings on Antique Guitars: A Cautionary tale

During the many years that I’ve been repairing and dealing in vintage guitars I’ve had the pleasure of the company of many 19th century Martin guitars and other quality made antique guitars. While these old guitars have landed here for a variety of repairs, one of the most common issues is bridge and top damage due to the use of steel strings. Similarly, bridge plate damage and bracing distortion can also accompany the use of steel strings on these lightly built guitars. During the 19th century metal strings were not yet in use on the guitar. Gut strings were standard and the guitars were built according to the expected tension load of the strings of the day. Given the low tension of gut strings the guitars of the 19th century were built much lighter than their steel string cousins.

There are several significant issues of construction and design in 19th century guitars that relate directly to the tension load that these instruments were meant to bear. Necks during the 19th century didn’t have metal reinforcement, meaning that many 19th century necks simply don’t have the overall stiffness necessary to carry the load of steel strings without exhibiting excessive relief. As significant (and the subject of the repair to be described later in this article) is the fact that the top thickness on a 19th century guitar is significantly less than a steel string. Bridge plate thickness is about 1/3 of a typical modern steel string guitar and brace gauge is typically much lighter as well. All of this adds up to potential trouble, I’d say likely trouble, when putting steel strings on an antique guitar. It is my opinion, based on the construction elements that I have noted, that steel strings should never be used on 19th and early 20th century guitars. The comparatively high tension of steel strings overload the top and can be the cause of significant damage to the instrument.

There are a variety of opinions out there regarding the use of steel strings on antique guitars. Many players like the idea of owning a 19th century guitar but are of the opinion that steel strings will make the guitar sound better than gut or nylon. That is highly debatable, but it is not my intention to argue this issue on the basis of tone but rather the structural risks of using steel on guitars designed for gut. Many dealers, upon acquiring an antique instrument, will put extra light or silk and steel strings on the guitar, but it is my opinion that this is done most frequently because dealers know that antique guitars strung with gut or nylon are hard to sell. A gut strung guitar is of little musical interest to most modern players, but if changed to steel the guitar becomes easier to sell.

A common misconception that contributes to the use of steel on antique Martin guitars is the notion that the presence of X bracing means that the guitar was built for steel strings. The fact is that Martin (and some other makers like Schmidt and Maul, Heinrich Schatz, Schroeder, and others) were using X bracing decades before steel strings were even made for use on the guitar. There are examples of X braced Martin guitars from the 1840s, a full 80 years prior to Martin offering their first guitar built specifically for steel strings. Some players (and many dealers) are unaware of these construction and design issues (lighter tops, bracing and bridge plate) or simply choose to ignore them.

Repair of an 1850s Martin with top damage due to the use of steel strings

This beautiful little Martin from the 1850s arrived in the shop with its bridge badly buckled and the top heavily torqued and bellied due to bridge rotation. The first photo shows the steel strings that had been in use still on the guitar. The original pyramid bridge was still on the guitar but holding on only by some splintered spruce beneath. The bridge was split from end to end and warped severely. A previous attempt had been made to repair the bridge by gluing an ebony veneer to the underside, an obvious attempt to stiffen the bridge. It is likely that the bridge cracked previously and this repair was an effort to save that original bridge. The bridge had also been bolted down to the top through the points of the pyramid. This sort of extraordinary effort (bolting and repairing the previous split) is the result of the use of steel strings on this antique guitar. A guitar like this was never meant to bear that tension load and cannot bear it over time without serious damage.

The goal of this repair was to remove the bridge, repair the top and replace the bridge plate, install a replica bridge and hopefully flatten the top distortion that had occurred. The first step was to remove the bridge. The bridge was heated in order to loosen the old hide glue that heldit to the top. As you can see from the pics, a fair chunk of spruce came up with the bridge.When the bridge buckled under tension and was left to twist or rotate the top the eventual result was cross grain breakage of the spruce top through the pin holes and also at the front edge ofthe bridge. You can see that a piece of the original mahogany bridge plate remained attached to the bridge as well, it having broken just like the spruce.

With the bridge off of the guitar you can see the amount of distortion or rotation evident in the top. The back edge of thebridge footprint on the top was rotated almost a full ¼” with a belly behind it that extended to the tone bar below the bridge plate. With theremains of the bridge plate in place the top remained quite stiff andresistant to being pressed flat. The shards of the original plate were removed with moisture and heat, after which the top loosenedup quite a bit. Using a desk lamp and a 100 watt light bulb, the top was heated gently and moistened slightly(on the inside). A seriesof shaped clamping cauls were made to place inside the guitar to allow the top to be clamped flat. The top was clamped to cool and dry, and leftclamped for about a week.


After the week of being set under clamps to flatten the top the clamps were removed and thetop evaluated. You can see by the photos that it still was not completely flat but wasconsiderably flatter than when this repair was started. A top with this sort of distortion typically won’t return to be entirely flat without some enhanced structural support, and so a new bridge plate was made for the guitar that was slightly larger than the original (about 1/8” larger on the front edge and back edge). The larger plate is installed to jump over the hole through the top and to stiffen the bridge area a little more than the originalwould have. Typically I would not install an oversized plate on a guitar like this but the loss of stiffness caused by the damage to the spruce requires a little more surface area to stabilize the top. The bridge plate was made to original thickness and made in mahogany to match the original material. The surface of the plate was treated with potassium dichromate in order to oxidize the wood and make it appear as old as the interior of the guitar. The new bridge platewas then installed into the body. The plate finished the job of flattening the top very nicely and without adding significant mass to the soundboard.




Next a graft of spruce was fashioned to fill the void left by the spruce that tore out of the top when the bridge and top buckled. The spruce graft was fit to the void and glued into place. The graft was left tall for the installation and then trimmed flush with a sharp chisel once the glue was dry. This step completed the repair of the top, stiffening the area and providing a solid gluing surface for the new bridge.

A new bridge in the proper size and style was made out of ebony for installation on the guitar. The original saddle was used in thenew bridge. Note the original pearl “flower” ornament under the bridge, an elegant detail of this early guitar. The photos show that once the guitar was strung to tension the top remained quite flat, showing none of the heavy belly and twist that was present when it came into the shop.

This was a costly repair, and quite invasive to the guitar. To my original point, none of this would have been necessary had a previous owner strung the guitar with appropriate strings. Luckily it was repairable, and the guitar restored to playable condition. But I’m sure that most owners and lovers of vintage instruments would agree that it would have been preferable if the damage never occurred. Owners of these fine 19th century guitars should take heed, and use nylon or gut strings only on such an instrument.